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Abstract Background Within the past years, umbilical cord (UC) and amniotic membrane (AM) expanded in human platelet lysate (PL) have been found to become increasingly candidate of mesenchymal stromal cells (MSCs) in preclinical and clinical studies. Different sources of MSCs have different properties, and lead to different therapeutic applications. However, the similarity and differences between the AMMSCs and UCMSCs in PL remain unclear. Results In this study, we conduct a direct head-to-head comparison with regard to biological characteristics (morphology, immunophenotype, self-renewal capacity, and trilineage differentiation potential) and immunosuppression effects of AMMSCs and UCMSCs expanded in PL. Our results indicated that AMMSCs showed similar morphology, immunophenotype, proliferative capacity and colony efficiency with UCMSCs. Moreover, no significantly differences in osteogenic, chondrogenic and adipogenic differentiation potential were observed between the two types of cells. However, AMMSCs exhibited higher PGE2 expression and IDO activity compared with UCMSCs when primed by IFN-γ and (or) TNF-α induction, and AMMSCs showed a higher inhibitory effect on PBMCs proliferation than UCMSCs. Conclusion The results suggest that AMMSCs expanded in PL showed similar morphology, immunophenotype, self-renewal capacity, and trilineage differentiation potential with UCMSCs. However, AMMSCs possessed superior immunosuppression effects in comparison with UCMSCs. These results suggest that AMMSCs in PL might be more suitable than UCMSCs for treatment of immune diseases. This work provides a novel insight into choosing the appropriate source of MSCs for treatment of immune diseases.

Background. Cavernous hemangioma is a rare benign tumor that develops from the adrenal glands. In this study, we present our experience with patients with adrenal cavernous hemangiomas (ACH) in a Chinese population. Methods. Demographic, diagnostic, surgical, and pathological findings in patients at a single institution who were adrenalectomized as a result of ACH were retrospectively reviewed. Results. Among 601 patients who underwent adrenalectomy, 8 (1.33%; 5 men, 3 women) cases were diagnosed with ACH between January 1, 1998, and December 31, 2018, in a single institution. The mean age was 53.25 ± 11.9 years (range, 35–67 years). Four (50%) were asymptomatic, and three (37.5%) complained of abdominal or flank discomfort. Preoperative computed tomography (CT) revealed ACH in 3 (37.5%) cases. Well-defined borders and heterogeneous enhancement with characteristic progressive partial filling-in were characteristic CT features of ACH (tumor size>3 cm). The mean tumor size was 5.16 ± 3.4 cm (range, 1.5–11 cm). No recurrence occurred during a median follow-up period of 38.37 months (range, 8–60 months). Conclusions. ACH was asymptomatic in most cases, and diagnosis could be challenging. Adrenalectomy is a safe treatment modality for ACH, and it ensures favorable outcomes.

Introduction Polycystic ovary syndrome (PCOS) is one of the leading causes of female infertility, affecting around 5% of women of childbearing age in China. Vitamin D insufficiency is common in women with PCOS and is associated with lower live birth rates. However, evidence regarding the effectiveness of vitamin D supplementation in women with PCOS is inconclusive. This multicentre randomised, double-blinded, placebo-controlled trial aims to evaluate the effectiveness of vitamin D supplementation prior to in vitro fertilisation (IVF) on the live birth rate in women with PCOS.Methods and analysis We plan to enrol women with PCOS scheduled for IVF. After informed consent, eligible participants will be randomised in a 1:1 ratio to receive oral capsules of 4000 IU vitamin D per day or placebo for around 12 weeks until the day of triggering. All IVF procedures will be carried out routinely in each centre. The primary outcome is live birth after the first embryo transfer. The primary analysis will be by intention-to-treat analysis. To demonstrate or refute that treatment with vitamin D results in a 10% higher live birth rate than treatment with placebo, we need to recruit 860 women (48% vs 38% difference, anticipating 10% loss to follow-up and non-compliance, significance level 0.05 and power 80%).Ethics and dissemination This study has been approved by the Ethics Committee in Women’s Hospital of Zhejiang University on 2 March 2020 (reference number: IRB-20200035-R). All participants will provide written informed consent before randomisation. The results of the study will be submitted to scientific conferences and a peer-reviewed journal.Trial registration number NCT04082650.

The mammary gland is a remarkably dynamic organ of milk synthesis and secretion, and it experiences drastic structural and metabolic changes during the transition from dry periods to lactation, which involves the expression and regulation of numerous genes and regulatory factors. Long non-coding RNA (lncRNA) has considered as a novel type of regulatory factors involved in a variety of biological processes. However, their role in the lactation cycle of yak is still poorly understood. To reveal the involved mechanism, Ribo-zero RNA sequencing was employed to profile the lncRNA transcriptome in mammary tissue samples from yak at two physiological stages, namely lactation (LP) and dry period (DP). Notably, 1,599 lncRNA transcripts were identified through four rigorous steps and filtered through protein-coding ability. A total of 59 lncRNAs showed significantly different expression between two stages. Accordingly, the results of qRT-PCR were consistent with that of the transcriptome data. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that target genes of differentially expressed lncRNAs (DELs) were involved in pathways related to lactation, such as ECM-receptor interaction, PI3K-Akt signaling pathway, biosynthesis of amino acids and focal adhesion etc. Finally, we constructed a lncRNA-gene regulatory network containing some well known candidate genes for milk yield and quality traits. This is the first study to demonstrate a global profile of lncRNA expression in the mammary gland of yak. These results contribute to a valuable resource for future genetic and molecular studies on improving milk yield and quality, and help us to gain a better understanding of the molecular mechanisms underlying lactogenesis and mammary gland development of yak.

Camel meat could have health benefits for human consumers due to its nutritional value. The influence of age and muscle type on the chemical composition and quality characteristics of Bactrian camel meat was examined in the present study. Samples of the Longissimus thoracic (LT), Semitendinosus (ST), and Psoas major (PM) muscles were collected from a total of fifteen male camels in three different age groups (3–4 years, 6–7 years, and 9–10 years). The younger camels exhibited higher values of moisture, polyunsaturated fatty acids, ultimate pH, cooking loss, and lightness, but lower fat, shear force, and redness values compared to meat collected from older camels. The LT muscle had higher fat and color parameters (lightness, redness, yellowness) but lower shear force values than the ST and PM muscles (p < 0.05). The ST muscles had a higher content of n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids but lower cooking loss values than the LT and PM muscles. These results indicated that younger camels provide better meat quality traits than older camels. The results of the present study will improve the marketing of Bactrian camel meat products and will provide more information about the most suitable muscles and the optimal slaughter age.

Cowpea mild mottle virus (CpMMV) is an economically significant virus that causes severe disease on several legume crops. Aside from recombination, other factors driving its rapid evolution are elusive. In this study, the synonymous codon pattern of CpMMV and factors shaping it were analyzed. Phylogeny and nucleotide composition analyses showed that isolates of different geography or hosts had very similar nucleotide compositions. Relative synonymous codon usage (RSCU) and neutrality analyses suggest that CpMMV prefers A/U-ending codons and natural selection is the dominative factor that affects its codon bias. Dinucleotide composition and codon adaptation analyses indicate that the codon pattern of CpMMV is mainly shaped by the requirement of escaping of host dinucleotide-associated antiviral responses and translational efficiency.

Superoxide dismutase and catalase are two major antioxidant enzymes in the fish antioxidant defense system, which can remove excess reactive oxygen species and protect fish from stress-induced oxidative damage. The present study aimed to clone the sequences of Yangtze sturgeon, Acipenser dabryanus, Cu/Zn superoxide dismutase (AdCu/Zn-SOD) and catalase (AdCAT), and to explore changes of gene expression in the liver and intestine during fasting and refeeding. A total of 120 fish were exposed to four fasting and refeeding protocols (fasting for 0, 3, 7, or 14 d and then refeeding for 14 d). The coding sequences of AdCu/Zn-SOD and AdCAT encoded 155 and 526 amino acid proteins, respectively, both of which were expressed mainly in the liver. During fasting, when compared to the control group, liver AdCu/Zn-SOD expression was significantly higher in the 3- and 14-d groups, whereas its intestinal expression increased significantly only in the 7-d group. Liver AdCAT expression increased significantly in the 3-, 7-, and 14-d groups. During refeeding, liver AdCu/Zn-SOD expression increased significantly in the 3-, 7-, and 14-d groups compared with those in the control group. Similarly, intestinal AdCu/Zn-SOD expression increased significantly in the 3- and 7-d groups. Moreover, intestinal AdCAT expression was significantly higher in the 3-d group than in the control group, but decreased significantly in the 14-d group. Our findings indicated that AdCu/Zn-SOD and AdCAT play important roles in protecting fish against starvation-induced oxidative stress. Yangtze sturgeon exhibited the potential to adapt to a starvation and refeeding regime.

The mammary gland is a complicated organ comprising several types of cells, and it undergoes extensive morphogenetic and metabolic changes during the female reproductive cycle. RNA editing is a posttranscriptional modification event occurring at the RNA nucleotide level, and it drives transcriptomic and proteomic diversities, with potential functional consequences. RNA editing in the mammary gland of yaks, however, remains poorly understood. Here, we used REDItools to identify RNA editing sites in mammary gland tissues in yaks during the lactation period (LP, n = 2) and dry period (DP, n = 3). Totally, 82,872 unique RNA editing sites were identified, most of which were detected in the noncoding regions with a low editing degree. In the coding regions (CDS), we detected 5235 editing sites, among which 1884 caused nonsynonymous amino acid changes. Of these RNA editing sites, 486 were found to generate novel possible miRNA target sites or interfere with the initial miRNA binding sites, indicating that RNA editing was related to gene regulation mediated by miRNA. A total of 14,159 RNA editing sites (involving 3238 common genes) showed a significant differential editing level in the LP when compared with that in the DP through Tukey’s Honest Significant Difference method (p < 0.05). According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, genes that showed different RNA editing levels mainly participated in pathways highly related to mammary gland development, including MAPK, PI3K-Akt, FoxO, and GnRH signaling pathways. Collectively, this work demonstrated for the first time the dynamic RNA editome profiles in the mammary gland of yaks and shed more light on the mechanism that regulates lactation together with mammary gland development.

The usage of animal serum may ultimately prevent the application of ex vivo cultured mesenchymal stromal cells (MSCs) in a clinical setting due to safety concerns and batch-to-batch variability. Increasing regulatory pressure to limit use of animal serum has been issued and serum-free, xeno-free, and chemically defined media (S&XFM-CD) is encouraged to replace serum-containing media (SCM) in the stem cell preparation process. We previously developed a S&XFM-CD for the expansion of umbilical cord-derived MSCs (UCMSCs). Different culture conditions affect the function of MSCs, which may further affect the therapeutic efficiency and mechanisms of action. In this study, we compared the therapeutic effect and mechanism of UCMSCs in S&XFM-CD (UCMSCS&XFM−CD) in experimental colitis with those in SCM (UCMSCSCM). UCMSCS&XFM−CD exhibited better therapeutic effects than UCMSCSCM by body weight, disease activity index, and histological colitis score. UCMSCS&XFM−CD or UCMSCSCM migrated to the inflammation site of injured colon, but exhibited low levels of recruitment and persistence. Systemic depletion of endogenous macrophages impaired the therapeutic effects of UCMSCSCM and UCMSCS&XFM−CD. Furthermore, UCMSCS&XFM−CD more markedly promoted intestinal macrophage polarisation from M1 to M2 phenotype to produce higher levels of IL-10 and lower levels of TNF-α in colon tissue than UCMSCSCM, while a higher level of IL-4 was produced in UCMSCSCM-treated group. UCMSCS&XFM−CD cocultured with RAW264.7 cells in a transwell system promoted the release of TSG-6 and IL-6, whereas UCMSCSCM increased PGE2 levels. Taken together, we demonstrated that UCMSCs in S&XFM-CD exhibited improved therapeutic effects with altered cytokine secretion in an experimental acute colitis model.

Long non-coding RNAs (lncRNAs) have been extensively studied in recent years. Numerous lncRNAs have been identified in mice, rats, and humans, some of which play important roles in muscle formation and development. However, little is known about lncRNA regulators that affect muscle development in yak (Bos grunniens). LncRNA expression during skeletal muscle development in yak was analyzed by RNA sequencing at three development stages: 3 years (group A), 6 months (group M), and 90-day-old fetuses (group E). A total of 1180 lncRNAs were identified in the three development stages. Compared with group E, 154 were upregulated and 130 were downregulated in group A. Compared with group A, 31 were upregulated and 29 were downregulated in group M. Compared with group E, 147 were upregulated and 149 were downregulated in group M (padj < 0.001, |log2FC| > 1.2). In addition, functional annotation analysis based on gene ontology (GO) and the Kyoto protocol encyclopedia of genes and genomes (KEGG) database showed that differentially expressed lncRNAs (DElncRNAs) were cis–trans target genes. The results showed that DElncRNAs were mainly involved in PI3K-Akt signaling pathway, focal adhesion, MAPK signaling pathway, apoptosis, and p53 signaling pathway. Furthermore, RTL1, IGF2, MEF2C, Pax7, and other well-known muscle development regulators were included in a co-expression network of differentially expressed target genes and lncRNAs. These data will help to further clarify the function of lncRNAs in the different stages of skeletal muscle developmental in yak.

Domestic yak (Bos grunniens) is the most crucial livestock in the Qinghai-Tibetan Plateau, providing meat and other necessities for local people. The skeletal muscle of adult livestock is composed of muscle fibers, and fiber composition in muscle has influence on meat qualities, such as tenderness, pH, and color. Real-time quantitative polymerase chain reaction (RT-qPCR) is a powerful tool to evaluate the gene expression of muscle fiber, but the normalization of the data depends on the stability of expressed reference genes. Unfortunately, there is no consensus for an ideal reference gene for data normalization in muscle tissues of yak. In this study, we aimed to assess the stability of 14 commonly used candidate reference genes by using five algorithms (GeNorm, NormFinder, BestKeeper, Delat Ct and Refinder). Our results suggested UXT and PRL13A were the most stable reference genes, while the most commonly used reference gene, GAPDH, was most variably expressed across different muscle tissues. We also found that the extensor digitorum lateralis (EDL), trapezius pars thoracica (TPT), and psoas major (PM) muscle had the higher content of type I muscle fibers and the lowest content of type IIB muscle fibers, while gluteobiceps (GB) muscle had the highest content of type IIB muscle fibers. Our study provides the suitable reference genes for accurate analysis of yak muscle fiber composition.

Abstract Background The practice of dehorning yak raises animal safety concerns, which have been addressed by selective breeding to obtain genetically hornless yak. The POLLED locus in yak has been studied extensively; however, little is known regarding the proteins that regulate horn bud development. Methods A differential proteomic analysis was performed to compare the skin from the horn bud region of polled yak fetuses and the horn bud tissue of horned yak fetuses using isobaric tags for relative and absolute quantitation (iTRAQ) technology coupled with 2D LC-MS/MS. Results One hundred differentially abundant proteins (DAPs) were identified. Of these, 29 were up-regulated and 71 were down-regulated in skin from the horn bud region of polled fetuses when compared to the horn bud tissue of horned fetuses. Bioinformatics analyses showed that the up-regulated DAPs were mainly associated with metabolic activities, while the down-regulated DAPs were significantly enriched in cell adhesion and cell movement activities. Conclusions We concluded that some important proteins were associated with cell adhesion, cell motility, keratinocyte differentiation, cytoskeleton organization, osteoblast differentiation, and fatty acid metabolism during horn bud development. These results advance our understanding of the molecular mechanisms underlying horn development.

Background: Doppler echocardiography (D-ECHO) is a commonly used imaging tool for both diagnosis and follow-up examination of congenital heart disease (CHD). The goal of this study is to evaluate the accuracy of D-ECHO as used to measure an estimate sPAP in pediatric patients with CHD.Methods: A prospective study in 397 pediatric patients with CHD has been carried out to compare estimate sPAP measured with D-ECHO to that measured with right heart catheterization (RHC). Pearson correlation analyses were used to calculate the correlation coefficients between RHC and D-ECHO. Bland-Altman analyses were carried out to assess the agreement between the two methods.Results: Our data have demonstrated a significant underestimation of sPAP by D-ECHO compared to that by RHC. A strong correlation (r = 0.957, p < 0.01) was found between sPAP (36.1 ± 14.9 mmHg) and RVSP (36.0 ± 14.5 mmHg) measured with RHC. However, a relatively weak correlation (r = 0.219, p < 0.01) was observed between sPAP (36.1 ± 14.9 mmHg) measured during RHC and sPAP (28.7 ± 9.7 mmHg) as estimated using D-ECHO. The Bland-Altman analysis demonstrated that the bias for D-ECHO sPAP estimates was 6.6 mmHg with 95% limits of agreement ranging from −23.6 to 36.8 mmHg. A total of 57.5% of D-ECHO measurements were found to be accurate, with accuracy predefined as 95% of agreement within ±10 mmHg for sPAP estimates.Conclusions: sPAP measured with D-ECHO may be underestimated in pediatric patients with CHD.

Qilian yak (Bos grunniens) is a local breed of yak with high adaptation to the high-elevation, cold, and anoxic environments. In this study, its complete mitochondrial genome was assembled from high-throughput sequencing reads. The mitogenome is 16,324 bp long with an A + T-biased nucleotide composition and has the typical set of 37 animal mitochondrial genes and the noncoding control region. Phylogenetic analysis supported the monophyly of the subfamilies Aepycerotinae, Alcelaphinae, Bovinae, Caprinae, and Cephalophinae, confirmed the polyphyly of the family Antilopinae within the family Bovidae, and indicated the close relatedness between domestic yaks (Bos grunniens) and wild yaks (Bos mutus).

Microbial contamination is one of the most common food safety issues that lead to food spoilage and foodborne illness, which readily affects the health of the masses as well as gives rise to huge economic losses. In this study, Channa argus was used as a source of antimicrobial agent that was then analyzed by untargeted metabolomics for its antibacterial mechanism against Staphylococcus aureus. The results indicated that the skin mucus extract of C. argus had great inhibitory action on the growth of S. aureus, and the morphology of S. aureus cells treated with the skin mucus extract exhibited severe morphological damage under scanning electron microscopy. In addition, metabolomics analysis revealed that skin mucus extract stress inhibited the primary metabolic pathways of S. aureus by inducing the tricarboxylic acid cycle and amino acid biosynthesis, which further affected the normal physiological functions of biofilms. In conclusion, the antimicrobial effect of the skin mucus extract is achieved by disrupting cell membrane functions to induce an intracellular metabolic imbalance. Hence, these results conduce to amass novel insights into the antimicrobial mechanism of the skin mucus extract of C. argus against S. aureus.

Yak reproductive characteristics have received extensive attention, though the molecular regulation mechanism of its ovarian activity remains to be explored. Therefore, this study initially conducted a comparative analysis of yak ovarian activities in anestrus, estrus, and pregnancy regarding their morphology and histology, followed by implementing RNA sequencing (RNA-seq) technology to detect the overall gene expression and biological mechanism in different reproductive stages. H&E staining showed that there were more growing follicles and mature follicles in ovarian tissue sections during estrus than ovarian tissues during non-estrus. The RNA-seq analysis of yak ovary tissues in three periods showed that DEGs related to follicular development and hormone metabolism were screened in the three comparison groups, such as COL1A2, NR4A1, THBS2, PTGS2, SCARB1, STAR, and WNT2B. Bioinformatics analysis showed that these DEGs are involved in ion binding, cell development, metabolic processes, enriched in ECM–receptor interactions, steroid biosynthesis, together with aldosterone generation/discharge and Wnt/PI3K-Akt signaling pathways. In addition, we speculate alternate splice development events to have important role/s in regulating ovarian functional genomic expression profiles. These results provide essential knowledge aimed at scrutinizing pivotal biomarkers for yak ovarian activity, together with paving the way for enhancing researchers’ focus on improving yak reproductive performance.

Reverse transcription quantitative real-time PCR (RT-qPCR) is widely used to study the relative abundance of mRNA transcripts because of its sensitivity and reliable quantification. However, the reliability of the interpretation of expression data is influenced by several complex factors, including RNA quality, transcription activity, and PCR efficiency, among others. To avoid experimental errors arising from potential variation, the selection of appropriate reference genes to normalize gene expression is essential. In this study, 10 commonly used reference genes - ACTB, B2M, HPRT1, GAPDH, 18SrRNA, 28SrRNA, PPIA, UBE2D2, SDHA, and TBP - were selected as candidate reference genes for six fetal tissues (heart, liver, spleen, lung, kidney, and forehead skin) of yak (Bos grunniens). The transcription stability of the candidate reference genes was evaluated using geNorm, NormFinder, and BestKeeper. The results showed that the combination of TBP and ACTB provided high-quality data for further study. In contrast, the commonly used reference genes 28SrRNA, SDHA, GAPDH, and B2M should not be used for endogenous controls because of their unstable expression in this study. The reference genes that could be used in future gene expression studies in yaks were indentified.

Sweet potato (Ipomoea batatas) is one of the largest food crops in the world. Due to its abundance of starch, sweet potato is a valuable ingredient in food derivatives, dietary supplements, and industrial raw materials. In addition, due to its ability to adapt to a wide range of harsh climate and soil conditions, sweet potato is a crop that copes well with the environmental stresses caused by climate change. However, due to the complexity of the sweet potato genome and the long breeding cycle, our ability to modify sweet potato starch is limited. In this review, we cover the recent development in sweet potato breeding, understanding of starch properties, and the progress in sweet potato genomics. We describe the applicational values of sweet potato starch in food, industrial products, and biofuel, in addition to the effects of starch properties in different industrial applications. We also explore the possibility of manipulating starch properties through biotechnological means, such as the CRISPR/Cas-based genome editing. The ability to target the genome with precision provides new opportunities for reducing breeding time, increasing yield, and optimizing the starch properties of sweet potatoes.

Living at a high altitude involves many environmental challenges. The combined effects of hypoxia and cold stress impose severe physiological challenges on endothermic animals. The yak is integral to the livelihood of the people occupying the vast, inhospitable Qinghai–Tibetan plateau and the surrounding mountainous region. Due to long-term selection, the yak exhibits stable and unique genetic characteristics which enable physiological, biochemical, and morphological adaptations to a high altitude. Thus, the yak is a representative model for mammalian plateau-adaptability studies. Understanding coping mechanisms provides unique insights into adaptive evolution, thus informing the breeding of domestic yaks. This review provides an overview of genetic adaptations in Bos grunniens to high-altitude environmental stress. Combined genomics and theoretical advances have informed the genetic basis of high-altitude adaptations.

This study aimed to explore the differences in fat deposition between female (FYs) and male yaks (MYs). Compared with MYs, the tenderness, L*, marbling, absolute content of fat, and most fatty acids (FAs) of longissimus dorsi (LD) in FYs were higher or better (p < 0.05), whereas the relative content of polyunsaturated fatty acids (PUFAs) and n-3 PUFAs were lower (p < 0.01). The absolute content of fat, C18:0, cis-C18:2, cis-C18:1, and C24:0 were positively correlated with L*45 min, b*24 h, tenderness, and marbling score of LD in FYs and MYs (p < 0.05), respectively. LPL, FATP2, ELOVL6, HADH, HACD, and PLINS genes play a crucial role in improving the marbling score and tenderness of yak meat. The results of gene expression and protein synthesis showed the effect of gender to FA biosynthesis, FA transport, lipolysis, and FA oxidation in the adipose tissue of yak was realized by the expressions of ME1, SCD, ACSL5, LPL, FABP1, PLIN4, and PLIN2 in peroxisome proliferators-activated receptor (PPAR) signaling. This study established a theoretical basis for the improvement of the meat quality of yak and molecular breeding.

Sibu yak is famous for its excellent breed in Tibet and has become a magic way for local herdsmen to get rich. The Sibu yak, however, has been identified as an endangered bovine species. In this study, the complete mitochondrial genome of Sibu yak (Bos grunniens) was sequenced. The complete mitochondrial genome is a circular molecule with 16,324 bp in length, including 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes, and a non-coding control region (D-loop). The entire nucleotide composition is A(33.70%), T(27.27%), C(25,81%), G(13.21%), respectively. Except that ND6 and 7 tRNAs （tRNA-Glu,tRNA-Pro,tRNA-Cys, tRNA-Tyr, tRNA-Ala, tRNA-Asn, and tRNA-Gln) are encoded on the light strand, the remaining genes are encoded on the heavy strand. As a valuable resource, we have compared it to related Bos species to understand the evolutionary history of Sibu yak.

In the present study, we report the complete mitochondrial genome of Niangya yak (Bos grunniens) and its phylogenetic inferences. The complete mitochondrial DNA is a circular molecule with 16,322 bp length consisting of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region(D-loop). Both ND6 and 7 tRNAs (tRNA-Pro, tRNA-Glu, tRNA-Tyr, tRNA-Cys, tRNA-Asn, tRNA-Ala and tRNA-Gln) are encoded on the light strand, and the remaining genes are encoded on the heavy strand. The overall nucleotide composition is A(33.73%), T(27.28%), C(25.80%), G(13.19%) respectively. The content of C + G is 38.99%. Given that yak is indispensable for the Tibetan people, it is important to understand the genetic status of the population for further systematic genetics, evolutionary significance and protection of genetic resources. Therefore, to understand the evolutionary history of Niangya yak, the complete mitochondrial genome of Niangya yak was sequenced and compared with the mitochondrial genome of closely related Bos species.

Non-alcoholic fatty liver disease (NAFLD) is becoming a severe public health problem that is affecting a large proportion of the world population. Generally, NAFLD in patients is usually accompanied by obesity, hyperglycemia, insulin resistance (IR) and type 2 diabetes (T2D), for which numerous animal models have been generated in order to explore the pathogenesis and therapies of NAFLD. On the contrary, quite a number of NAFLD subjects, especially in Asian regions, are non-obese and non-diabetic; however, few animal models are available for the research of non-obese NAFLD. Here, four approaches (here called approach 1 to 4) corresponding to the variable compositions of diets were used to treat tree shrews (Tupaia belangeri chinensis), which have a closer evolutionary relationship to primates than rodents. Analysis of plasma biochemical parameters, hepatic histology, and the expression of hepatic lipid metabolic genes revealed that all four approaches led to hepatic lipid accumulation, liver injury and hypercholesterolemia, but had no effect on body weight and adipose tissue generation, or glycemia. Hepatic gene expression in tree shrews treated by approach 4 might suggest a different or non-canonical pathway leading to hepatic steatosis. In conclusion, the tree shrew displays hepatic steatosis and dyslipidemia, but remains non-obese and non-diabetic under high energy diets, which suggests that the tree shrew may be useful as a novel animal model for the research of human non-obese NAFLD.

Storage roots are the main sink for photo-assimilate accumulation and reflect cassava yield and productivity. Regulation of sugar partitioning from leaves to storage roots has not been elucidated. Cell wall invertases are involved in the hydrolysis of sugar during phloem unloading of vascular plants to control plant development and sink strength but have rarely been studied in root crops like cassava. MeCWINV3 encodes a typical cell wall invertase in cassava and is mainly expressed in vascular bundles. The gene is highly expressed in leaves, especially mature leaves, in response to diurnal rhythm. When MeCWINV3 was overexpressed in cassava, sugar export from leaves to storage roots was largely inhibited and sucrose hydrolysis in leaves was accelerated, leading to increased transient starch accumulation by blocking starch degradation and reduced overall plant growth. The progress of leaf senescence was promoted in the MeCWINV3 over-expressed cassava plants with increased expression of senescence-related genes. Storage root development was also delayed because of dramatically reduced sugar allocation from leaves. As a result, the transcriptional expression of starch biosynthetic genes such as small subunit ADP-glucose pyrophosphorylase, granule-bound starch synthase I, and starch branching enzyme I was reduced in accordance with insufficient sugar supply in the storage roots of the transgenic plants. These results show that MeCWINV3 regulates sugar allocation from source to sink and maintains sugar balance in cassava, thus affecting yield of cassava storage roots.

Background Yak (Bos grunniens) is the most important domestic animal for people living at high altitudes. Yak ordinarily feed by grazing, and this behavior impacts the accuracy of the pedigree record because it is difficult to control mating in grazing yak. This study aimed to evaluate the pedigree system and individual identification in polled yak. Methods A total of 71 microsatellite loci were selected from the literature, mostly from the studies on cattle. A total of 35 microsatellite loci generated excellent PCR results and were evaluated for the parentage testing and individual identification of 236 unrelated polled yaks. A total of 17 of these 35 microsatellite loci had polymorphic information content (PIC) values greater than 0.5, and these loci were in Hardy–Weinberg equilibrium without linkage disequilibrium. Results Using multiplex PCR, capillary electrophoresis, and genotyping, very high exclusion probabilities were obtained for the combined core set of 17 loci. The exclusion probability (PE) for one candidate parent when the genotype of the other parent is not known was 0.99718116. PE for one candidate parent when the genotype of the other parent is known was 0.99997381. PE for a known candidate parent pair was 0.99999998. The combined PEI (PE for identity of two unrelated individuals) and PESI (PE for identity of two siblings) were >0.99999999 and 0.99999899, respectively. These findings indicated that the combination of 17 microsatellite markers could be useful for efficient and reliable parentage testing and individual identification in polled yak. Discussion Many microsatellite loci have been investigated for cattle paternity testing. Nevertheless, these loci cannot be directly applied to yak identification because the two bovid species have different genomic sequences and organization. A total of 17 loci were selected from 71 microsatellite loci based on efficient amplification, unambiguous genotyping, and high PIC values for polled yaks, and were suitable for parentage analysis in polled yak populations.

(-)-Epigallocatechin-3-gallate (EGCG), which is the most abundant catechin in green tea, has many potential health benefits, including decreased weight gain and/or adipose tissue weight. Suggested mechanisms for body weight reduction by EGCG include: (1) a decrease in calorie intake and (2) activation of AMPK in liver, skeletal muscle, and white adipose tissue. However, only one study supports the AMPK hypothesis. To determine the role of AMPK in EGCG-induced reduction of body weight, we administrated 50 mg/kg and 100 mg/kg per day to mice, together with a high-fat diet (HFD), for 20 weeks. EGCG had a significant effect on obesity and decrease in epididymal adipose tissue weight, and also affected serum lipid characteristics, including triglyceride, cholesterol (CHOL), and high- and low-density lipoprotein CHOL (HDL-C, LDL-C) concentrations. In addition, EGCG increased the excretion of free fatty acids from feces. By measuring the mRNA expression levels of genes involved in lipid metabolism, we found that EGCG inhibited the expression of genes involved in the synthesis of de novo fatty acids (acc1, fas, scd1, c/ebpβ, pparγ, and srebp1) and increased the expression of genes associated with lipolysis (hsl) and lipid oxidization in white adipose tissue, in both the HFD and the EGCG groups. However, EGCG significantly increased the expression of genes involved in the synthesis of de novo fatty acids compared with the HFD group. Increased AMPK activity was found in both subcutaneous and epididymal adipose tissues. In conclusion, EGCG can decrease obesity and epididymal white adipose tissue weight in mice, only partially via activation of AMPK.

Genomic selection is a promising breeding strategy that has been used in considerable numbers of breeding projects due to its highly accurate results. Yak are rare mammals that are remarkable because of their ability to survive in the extreme and harsh conditions predominantly at the so-called “roof of the world”—the Qinghai–Tibetan Plateau. In the current study, we conducted an exploration of the feasibility of genomic evaluation and compared the predictive accuracy of early growth traits with five different approaches. In total, four growth traits were measured in 354 yaks, including body weight, withers height, body length, and chest girth in two early stages of development (weaning and yearling). Genotyping was implemented using the Illumina BovineHD BeadChip. The predictive accuracy was calculated through five-fold cross-validation in five classical statistical methods including genomic best linear unbiased prediction (GBLUP) and four Bayesian methods. Body weights at 30 months in the same yak population were also measured to evaluate the prediction at 6 months. The results indicated that the predictive accuracy for the early growth traits of yak ranged from 0.147 to 0.391. Similar performance was found for the GBLUP and Bayesian methods for most growth traits. Among the Bayesian methods, Bayes B outperformed Bayes A in the majority of traits. The average correlation coefficient between the prediction at 6 months using different methods and observations at 30 months was 0.4. These results indicate that genomic prediction is feasible for early growth traits in yak. Considering that genomic selection is necessary in yak breeding projects, the present study provides promising reference for future applications.

The breeding of yaks is highly seasonal, there are many crucial proteins involved in the reproduction control program, especially in follicular development. In order to isolate differential proteins between mature and immature follicular fluid (FF) of yak, the FF from yak follicles with different sizes were sampled respectively, and two-dimensional gel electrophoresis (2-DE) of the proteins was carried out. After silver staining, the Image Master 2D platinum software was used for protein analysis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was performed for differential protein identification. The expression level of transferrin and enolase superfamily member 1 (ENOSF1) was determined by Western blotting for verification analysis. The results showed that 2-DE obtained an electrophoresis map of proteins from mature and immature yak FF with high resolution and repeatability. A comparison of protein profiles identified 12 differently expressed proteins, out of which 10 of them were upregulated while 2 were downregulated. Western blotting showed that the expression of transferrin and ENOSF1 was enhanced with follicular development. Both the obtained protein profiles and the differently expressed proteins identified in this study provided experimental data related to follicular development during yak breeding seasons. This study also laid the foundation for understanding the microenvironment during oocyte development.

Long-term energy stress (ES) during the cold season is a serious problem for the breeding of yaks. In this paper, the response of fat metabolism in yaks to long-term ES during the cold season was studied. Gas chromatography (GC) analysis showed that the percentage of saturated fatty acids (SFAs) in the subcutaneous fat of the yaks in the ES group was 42.7%, which was less than the 56.6% in the CO group (p < 0.01) and the percentage of polyunsaturated unsaturated fatty acids (PUFAs) in the subcutaneous fat of the yaks in the ES group was 38.3%, which was more than the 26.0% in the CO group (p < 0.01). The serum analysis showed that fatty acid oxidation in yaks was increased under long-term ES. In the subcutaneous fat of yaks under long-term ES, the gene expression levels of glycerol-3-phosphate acyltransferase 4 (GPAT4), hormone-sensitive lipase (HSL), patatin-like phospholipase domain-containing protein 2 (PNPLA2), acyl-CoA dehydrogenase (ACAD), acyl-coenzyme A thioesterase 8 (ACOT8), facilitated glucose transporter (GLUT4), 3-oxoacyl-[acyl-carrier-protein] synthase (OXSM), oestradiol 17-beta-dehydrogenase 8 (HSD17B8) and malonate-Co-A ligase ACSF3 (ACSF3) were downregulated (q < 0.05), whereas the gene expression levels of aquaporin-7 (AQP7), long-chain-fatty-acid-CoA ligase (ACSL), elongation of very long chain fatty acids protein (ELOVL) and fatty acid desaturase 1 (FADS1) were upregulated (q < 0.05), indicating the inhibition of fat catabolism, fat anabolism, fatty acid oxidation, glucose (GLU) intake and SFA synthesis and the promotion of glycerinum (GLY) transportation and PUFA synthesis. Additional findings showed that the gene expression levels of leptin (LEP), adenosine 5′-monophosphate-activated protein kinase (AMPK) and phosphatidylinositol 3-kinase (PI3K) were upregulated (q < 0.05), whereas the gene expression levels of malonyl-CoA decarboxylase (MCD), sterol regulatory element-binding protein 1 (SREBF1), mammalian target of rapamycin (mTOR) and serine/threonine-protein kinase (AKT) were downregulated (q < 0.05), indicating that fat metabolism in the subcutaneous fat of yaks under ES was mainly regulated by AMPK signaling and mTOR and PI3K-AKT signaling were also involved. Energy consumption was inhibited in the subcutaneous fat itself. This study can provide a theoretical basis for the healthy breeding and genetic breeding of yaks.

The yak (Bos grunniens) is subjected to nutritional deficiency during the whole winter grazing season; deciphering the adipose metabolism and energy homeostasis under cold and nutrients stress conditions could be a novel way to understand the specific mechanism of energy metabolism. Circular RNAs (circRNAs) have elucidated that they play a key role in many biological events, but the regulatory function of adipose development remains mostly unknown. Therefore, the expression pattern of circRNAs were identified for the first time during yak adipocyte differentiation to gain insight into their potential functional involvement in bovine adipogenesis. We detected 7203 circRNA candidates, most of them contained at least two exons, and multiple circRNA isoforms could be generated from one parental gene. Analysis of differential expression circRNAs displayed that 136 circRNAs were differentially expressed at day 12 (Ad) after adipocyte differentiation, compared with the control at day 0 (Pread 0), while 7 circRNAs were detected on day 2. Sanger sequencing validated that six circRNAs had head-to-tail junction, and quantitative real-time PCR (qPCR) results revealed that the expression patterns of ten circRNAs were consistent with their expression levels from RNA-sequencing (RNA-seq) data. We further predicted the networks of circRNA-miRNA-gene based on miRNAs sponging by circRNAs, in which genes were participated in the adipocyte differentiation-related signaling pathways. After that, we constructed several adipocyte differentiation-related ceRNAs and revealed six circRNAs (novel_circ_0009127, novel_circ_0000628, novel_circ_0011513, novel_circ_0010775, novel_circ_0006981 and novel_circ_0001494) were related to adipogenesis. Furthermore, we analyzed the homology among yak, human and mouse circRNAs and found that 3536 yak circRNAs were homologous to human and mouse circRNAs. In conclusion, these findings provide a solid basis for the investigation of yak adipocyte differentiation-related circRNAs and serve as a great reference to study the energy metabolism of high-altitude animals.

Testis has an important function in male reproduction. Its development is regulated by a large number of genes. The real-time reserve transcriptase-quantitative polymerase chain reaction (RT-qPCR) is a useful tool to evaluate the gene expression levels. However, unsuitable reference genes (RGs) can cause the misinterpretation of gene expression levels. Unfortunately, the ideal RGs for yak testis development are yet to be studied. In this study, 13 commonly used RGs were selected to identify the most stable RGs in yak testis at four different developmental stages, including two immature stages (6 months and 18 months) and two mature stages (30 months and 6 years). This study used GeNorm, NormFinder, BestKeeper, ∆Ct, and RefFinder programs to evaluate the stability of 13 candidate genes. The results of RefFinder showed that the stabilities of TATA box-binding protein (TBP) and ubiquitously expressed transcript protein (UXT) were ranked the top two across all developmental stages. TBP and hydroxymethylbilane synthase (HMBS) were stably expressed in immature stages, while mitochondrial ribosomal protein L39 (MRPL39) and TBP had higher stability than other candidate genes in mature stages. This study provided valuable information for gene expression studies to assist further investigation on the molecular mechanisms in underlying yak testis development.

Histological examination of testes is essential for understanding infertility, sex development, and growth. Therefore, to understand the histomorphology of testes at different developmental stages, we performed hematoxylin and eosin staining of Yak testis. Our results revealed that the diameters of spermatogenic cells and their nuclei were significantly larger (p < 0.05) in the testis at six years compared to at six and 18 months. No significant difference was noted between 30 months and six years. The study was designed to compare the expression profile of LHB in Datong yak. The expression pattern of LHB was explored using quantitative PCR, semi-quantitative PCR, molecular bioinformatic, and Western blot analysis. Our observations indicated that expression of LHB was significantly higher (p < 0.05) in the testis of Datong yak. Western blotting indicated that the molecular mass of LHB protein was 16 kDa in yak. The protein encoded by yak LHB included conserved cysteine-knot domain regions. The high expression of LHB in testis indicated that LHB may be vital for the development of male gonads and the fertility of Datong yak.

The aim of this study was to explore the possibility of applying GP to important economic traits in the domesticated yak, thus providing theoretical support for its molecular breeding. A reference population was constructed consisting of 354 polled yaks, measuring four growth traits and eight hematological traits related to resistance to disease (involved in immune response and phagocytosis). The Illumina bovine HD 770k chip was used to obtain SNP information of all the individuals. With these genotypes and phenotypes, GBLUP, Bayes B and Bayes Cπ methods were used to predict genomic estimated breeding values (GEBV) and assess prediction capability. The correlation coefficient of the association of GEBV with estimated breeding value (EBV) was used as PA for each trait. The prediction accuracy varied from 0.043 to 0.281 for different traits. Each trait displayed similar PAs when using the three methods. Lymphocyte counts (LYM) exhibited the highest predictive accuracy (0.319) during all GP, while chest girth (CG) provided the lowest predictive accuracy (0.043). Our results showed moderate PA in most traits such as body length (0.212) and hematocrit (0.23). Those traits with lower PA could be improved by using SNP chips designed specifically for yak, a better optimized reference group structure, and more efficient statistical algorithms and tools.

Investigating the critical genes related to milk synthesis is essential for the improvement of the milk yield of the yak. Real-time quantitative polymerase chain reaction (RT-qPCR) is a reliable and widely used method to measure and evaluate gene expression levels. Selection of suitable reference genes is mandatory to acquire accurate normalization of gene expression results from RT-qPCR. To select the most stable reference genes for reliable normalization of mRNA expression by RT-qPCR in the mammary gland of the Ashidan yak, we selected 16 candidate reference genes and analyzed their expression stability at different physiological stages (lactation and dry period). The expression stability of the candidate reference genes was assessed using geNorm, NormFinder, BestKeeper, Delta Ct, and RefFinder methods. The results showed that the hydroxymethylbilane synthase gene (HMBS) and the tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide gene (YWHAZ) were the most stable genes across all treatment samples. The reliability of selected reference genes was validated by normalizing relative expression of the lactation-related 60S ribosomal protein L35 gene (RPL35). The relative expression of RPL35 varied considerably according to the different reference genes. This work provides valuable information to further promote research in the molecular mechanisms involved in lactation and mammary gland development and provides a foundation for the improvement of the milk yield and quality of the Ashidan yak.

Testis-specific genes play an essential part in the centromere union during meiosis in male germ cells, spermatogenesis, and in fertility. Previously, there was no research report available on the expression pattern of SYCP3 and TSEG2 genes in different ages of yaks. Therefore, the current research compared the expression profiling of SYCP3 and TSEG2 genes in testes of yaks. The expression pattern of SYCP3 and TSEG2 mRNA was investigated using qPCR, semi-quantitative PCR, western blot, immunohistochemistry, and molecular bioinformatics. Our findings displayed that SYCP3 and TSEG2 genes were prominently expressed in the testicles of yaks as compared to other organs. On the other hand, the protein encoded by yak SYCP3 contains Cor1/Xlr/Xmr conserved regions, while the protein encoded by yak TSEG2 contains synaptonemal complex central element protein 3. Additionally, multiple alignments sequences indicated that proteins encoded by Datong yak SYCP3 and TSEG2 were highly conserved among mammals. Moreover, western blot analysis specified that the molecular mass of SYCP3 protein was 34-kDa and TSEG2 protein 90-kDa in the yak. Furthermore, the results of immunohistochemistry also revealed the prominent expression of these proteins in the testis of mature yaks, which indicated that SYCP3 and TSEG2 might be essential for spermatogenesis, induction of central element assembly, and homologous recombination.

Pamir yak (Bos grunniens) is a yak breed from Pamir Plateau with strong adaptation to the high-elevation, cold and anoxic environments. Its complete mitochondrial genome was determined to be 16,323 bp long with a moderately asymmetric nucleotide composition, and harbors the typical set of 37 mitochondrial genes and the noncoding control region. The PCGs start with the typical ATA or ATG codons, and end with TAA, TAG or the incomplete termination codon T. Phylogenetic analysis suggests that Pamir yak is most closely related to six other yak breeds (i.e. Datong, Pali, polled, Qilian, Seron and Sunan yaks).

Yak is an ancient breed and Bazhou Yak is also one of China's unique yak breed resources. In the present study, its complete mitochondrial genome was assembled from Illumina sequencing data and we identified the complete mitochondrial genome of the Bazhou yak (Bos grunniens). The complete mitochondrial DNA is a circular molecule with 16,325 bp length consisting of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region (D-loop). The overall nucleotide composition is A (33.69%), T (27.30%), C (25.79%), and G (13.22%), respectively. The content of C + G is 39.01%. Phylogenetic analysis of the mitochondrial genomes of 15 related species by MEGA7.0 showed that the genetic relationship of Bazhou yak is closer to Datong yak and polled yak.

Jinchuan yak was a newly discovered yak breed, not only possesses a large proportion of multi-ribs but also exhibits many good characteristics. However, there is limited information about its overall genetic structure. In this study, we assembled the mitochondrial genome for Jinchuan yak (Bos grunniens), the results show that the mitochondrial genome is 16,324bp long with an A + T-biased base composition (61.0% A + T) and harbours the typical set of 37 mitochondrial genes and 1 non-coding control region. The PCGs start with the typical ATA or ATG codons and are terminated with TAA, TAG or the incomplete stop codon T. Phylogenetic analysis suggests that Jinchuan yak is most closely related to Datong yak and Sunan yak.

Jialuo sheep is one of the important production materials of herdsmen in the pastoral areas of northwestern Sichuan in China. We reported the complete mitogenome of Jialuo sheep for the first time. It is 16,617 bp in length, containing 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region (D-loop). In the evolutionary relationship, the mitogenome of Jialuo sheep is closer to Texel sheep. This report will help the further studies of sheep species classification and resource protection.

In this study, we assembled the mitochondrial genome for Seron yak (Bos grunniens), a local yak breed with strong adaptation to marshy grasslands. The resultant mitochondrial genome is 16,325 bp long with an A + T-biased base composition (61.0% A + T) and harbours the typical set of 37 mitochondrial genes and 1 non-coding control region. The PCGs start with the typical ATA or ATG codons and are terminated with TAA, TAG or the incomplete stop codon T. Phylogenetic analysis supports the inclusion of Bison within the genus Bos, and suggests that Seron yak is most closely related to Datong yak and polled yak.

Tianjun yak (Bos grunniens) is a yak breed with strong adaptation to the high-elevation, cold and anoxic environments. Its complete mitochondrial genome is 16,323 bp long with an asymmetric base composition, and harbors the 37 typical mitochondrial genes and one noncoding control region. The PCGs are initiated with the typical ATA or ATG codons, and are terminated with TAA, TAG or the incomplete stop codon T––. Phylogenetic analysis suggests that Tianjun yak is most closely related to the polled yak.

In this study, we reconstructed the complete mitochondrial genome of the hybrid of Jersey cattle (Bos taurus; ♂) × Gannan yak (Bos grunniens; ♀) from Illumina sequencing reads. The mitochondrial genome is 16,322 bp in length with an A + T-biased nucleotide composition, and encodes 13 protein-coding genes, 22 tRNAs, and 2 rRNAs along with a noncoding control region. In addition, its gene order is identical to those of previously published mitochondrial genomes of the genera Bison and Bos. Phylogenetic analysis indicates that this hybrid is most closely related to Gannan yak and Jinchuan yak.

Datong horse processes a muscular physique with high tolerance to extensive management and adapts well to high altitude conditions in Qinghai, China. In this study, the whole mitochondrial genome sequence of E. caballus determined using next-generation sequencing data was 16,654 bp in length, consisting of 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and a non-coding control region. Notably, there was one tandem repeat with 21 ‘CACCTGTG’ located in the control region. The base composition of the genome was A (32.3%), C (28.6%), G (13.3%), and T (25.8%), with an A + T content of 58.1%. Molecular phylogeny demonstrated that E. caballus was more closely related to a breed from central Asia and processed distinct relationships with some Chinese breeds. This work characterized the mitogenome of E. caballus (Datong horse breed) and present significant genetic information for this valuable specimen.

Xueduo yak (Bos grunniens) is one of the native yak genetic resources of China. Here, the complete mitochondrial genome of the Xueduo yak was first sequenced in this study. The total length of this mitochondrial genome is 16,323 bp, with the base composition of 33.72% A, 27.28% T, 25.80% C, and 13.20% G. The genome has 37 genes, including 13 protein-coding genes, 22 tRNA genes, and two ribosomal RNA genes. The phylogenetic analysis showed that Xueduo yak is closely related to Qinghai Plateau yak and Maiwa yak. This complete mitochondrial genome sequence of Xueduo yak would be useful for further understanding the evolution and conservation of Xueduo yak.

Huanhu yak is a native yak species of China. In the present study, we reported the complete mitochondrial DNA sequence of the Huanhu yak. The complete mitochondrial genome is a circular molecule with 16,323 bp length which consisted of 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, and a non-coding control region (D-loop region). The overall nucleotide composition is 33.71% A, 27.26% T, 25.82% C, and 13.21% G, respectively. The phylogenetic analysis showed that the genetic relationship of Huanhu yak is closer to Pali yak.

Liangzhou donkey (Equus asinus) is one of the most important donkey species in China. In this study, we sequenced the complete mitochondrial genome by next-generation sequencing method, the results show it was 16,560 bp in length, consisting 37 genes: 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region. The base composition of the genome was 32.4% for A, 28.7% for C, 13.2% for G, and 25.7% for T； A + T for 58.1%. The phylogenetic analysis demonstrated that Liangzhou donkey was more closely related to Qingyang donkey and processed distinct relationships with other Chinese donkey breeds. This work characterized the mitochondrial genome of Equus asinus (Liangzhou donkey) and presents significant genetic information for this special species.

Maiwa yak is a unique local strain of yak breed resource in China. The complete mitochondrial genome was identified in this work. The mitochondrial DNA is a circular molecule with 16,324 bp in length, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding control region(D-loop). The overall nucleotide ratio is A (33.70%), G (13.22%), T (27.26%), C (25.82%) with a C + G content of 39.04%. Phylogenetic analysis of mitochondrial genomes of 17 close species using MEGA7.0 showed that Maiwa yak is most related to Pali yak and polled yak.

Yushu yak (Bos grunniens) is a local breed of yaks with strong adaptation to the high-altitude, cold, and anoxic environments. In this study, its complete mitochondrial genome was assembled from Illumina sequencing data. The genome was determined to be 16,324 bp in size with a moderately asymmetric nucleotide composition (61.0% A + T) and encodes the typical set of 37 mitochondrial genes. The PCGs are initiated with the typical ATA or ATG codons and are terminated with TAA, TAG, or the incomplete stop codon T––. Phylogenetic analysis suggests that Yushu yak is most closely related to Qinghai Plateau yak.

Elymus nutans is an alpine plant, which plays an important role in maintaining ecological system and the development of animal husbandry in the Tibetan region of China. However, the population of wild E. nutans notably decreased in recent years with overgrazing and ecological environment deterioration, and the germplasm resources have been threatened. This study reported a complete circular chloroplast genome of E. nutans, which was 134,147 bp in length, containing a pair of inverted repeats (IRs) of 10,541 bp separated by one small single copy (SSC) region of 14,036 bp and one large single copy (LSC) region of 99,029 bp. A total of 123 genes, including 87 protein-coding genes, 32 transfer RNA genes and four ribosomal RNA genes were predicted from the chloroplast genomes. The overall GC content of the chloroplast genome was 38.34% and the corresponding values of the IR, SSC and LSC were 48.7%, 32.4% and 37.0%, respectively. The results of phylogenetic analysis showed that wild E. nutans was clustered closely with Triticum aestivum.

Sunan yak is one of the unique and indigenous yak species in China. The complete mitochondrial genome sequence of the Sunan yak was first determined in this study. The mitochondrial DNA is a circular molecule with 16,322 bp in length, containing 12 protein-coding genes, two rRNA genes, 22 tRNA genes and a noncoding control region (D-loop), showed a typical mammal pattern. The overall nucleotide composition is A (33.71%), T(27.26%), C(25.82%), G(13.21%) with an A + T content of 60.97%. Phylogenetic analysis based on the mitochondrial genomes of 12 related species using MEGA 5.0 indicated that Sunan yak was most closely related to Qinghai Plateau yak and Maiwa yak.