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Cytochrome P450 Family 19 (CYP19) is a crucial enzyme to catalyze the conversion of androgens to estrogens. However, the regulatory mechanism of goose CYP19 gene remains poorly understood. The present study attempted to obtain the full-length coding sequence (CDS) and 5'-flanking sequence of CYP19 gene, to investigate its expression and distribution profiles in different sized follicles, and to analyze the transcriptional regulatory mechanism of CYP19 gene in goose. Results showed that its CDS consisted of 1512 nucleotides and the encoded amino acid sequence contained a classical P450 structural domain. Homology analysis showed that there were high homologies of nucleotide and amino acid sequences between goose and other avian species. Its promoter sequence spanned from -1925 bp to the transcription start site (ATG) and several transcriptional factors were predicted in this region. Further analysis from luciferase assay showed that the luciferase activity was the highest spanning from -118 to -1 bp by constructing deletion promoter reporter vector. In addition, result from quantitative real-time polymerase chain reaction indicated that the mRNA level of CYP19 gene were highly expressed in theca layer of the fifth largest follicle, and the cellular location was in the theca externa cells by immunohistochemistry. Taken together, it could be concluded that the transcription activity of CYP19 gene was activated by transcriptional factors in its proximal region of promoter to promote the synthesis of estrogens, regulating the selection of pre-hierarchical into hierarchical follicle in goose., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Anser cygnoides has a spherical crest on the beak roof, which is described as knob. However, the mechanisms affecting knob morphology are unclear. Here, we investigated the phenotypic characteristics and molecular basis of knob-size differences in Yangzhou geese. Anatomically, the knob was identified as frontal hump in the frontal area of the skull, rather than hump of upper beak. Although the frontal hump length, and height varied greatly in geese with different knob phenotypes, little was changed in the width. Histologically, knob skin in large-size knobs geese have a greater length in the stratum corneum, stratum spinosum, and stratum reticular than that in small-size knobs geese. Moveover, the 415 differentially expressed genes were found between the large knobs and small ones through transcriptome profiling. In addition, GO enrichment and KEGG pathway analysis revealed 455 significant GO terms and 210 KEGG pathways were enriched, respectively. Among these, TGF-β signaling and thyroid hormone synthesis-signaling pathways were identified to determine knob-size phenotype. Furthermore, BMP5, DCN, TSHR and ADCY3 were recognized to involve in the growth and development of knob. Our data provide comprehensive molecular determinants of knob size phenotype, which can potentially promote the genetic improvement of goose knobs.

This study aimed to evaluate the nutritional value of thigh meat from 4 Polish geese varieties. Protein, fat, and cholesterol content, as well as amino acid and fatty acid profiles, were determined. Based on the percentage of amino acid in protein and fatty acids in meat lipids, the health lipid indices were calculated. The experimental material covered thigh muscles from 17-week-old Kartuska (Ka), Suwalska (Su), Lubelska (Lu), and Kielecka (Ki) geese reared in a semi-intensive system. Muscle protein content did not differ significantly between varieties. The protein content of the Ka, Su, Lu, and Ki goose meat was deemed high-value as it contained all the essential amino acids in the proportions consistent with standard protein values. The muscles of all the researched geese varieties were characterized by a high level of Lys, which indicates that this meat is a good source of it (AAS Lys 240-280%). Current findings showed that polyunsaturated fatty acids (PUFA)/saturated fatty acids (SFA) and PUFA n-6/n-3 ratios in Ka, Su, Lu, and Ki muscles were found to be within the optimum values for human diets. No significant differences were observed in monounsaturated fatty acids, PUFA, and unsaturated fatty acids (UFA) between the analyzed muscles. The meat of Ka and Su contained significantly more lipids than Lu and Ki. A more beneficial amino acid profile was found in Ka meat due to a higher content of PUFA n-3 and the best n-6/n-3 ratio in comparison with other varieties. The muscles of the Ka variety also contained the least cholesterol. However, the Ki goose muscles stood out among other varieties with the least percentage of SFA, the highest share of docosahexaenoic acid (C 22:6 n-3), as well as the most beneficial value of the following indices: UFA/SFA, hypocholesterolemic fatty acid/hypercholesterolemic fatty acid ratio, and nutritive value index. The thigh muscles of Ka, Su, Lu, and Ki were characterized by an atherogenicity index that met the levels of recommended values (<1) in the diet of a human being, while the thrombogenicity index was slightly higher than the recommended value (<0.5)., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

We studied the correlations between egg geometrical parameters (i.e., egg shape index, sphericity, geometric mean diameter, surface area, and volume) and eggshell qualities, or the organic matrix in eggshell. Eggs were collected from 5 poultry breeds belonging to 3 species (commercial Hy-line Brown Chicken, Shaoxing Duck, Jinding Duck, Taihu Goose, and Zhedong White Goose). The geometrical parameters showed high variation among 3 species of poultry, and even between breeds in the same species. The five geometrical parameters were grouped into 2 sets, one contained shape index and sphericity, the other comprised geometric mean diameter, surface area, and volume. The parameters in the same set can be perfectly fitted to one another. Egg weight, shell membrane weight, and calcified shell weight were significantly correlated with geometric mean diameter, surface area, and volume. In accordance with false discovery rate-adjusted P value, both shell membrane relative weight and calcified shell thickness showed no significant correlations with any of the geometrical parameters. However, the correlations between geometrical parameters and other shell variables (calcified shell weight, shell relative weight, calcified shell thickness uniformity, and eggshell breaking strength) depend on breed. Both constitutive proportions and percentage contents of 3 eggshell matrix components (acid-insoluble, water-insoluble, and both acid and water facultative-soluble matrix) had no effects on egg shape and size. The correlations between the amounts of various shell matrix, egg shape and size depend on breed or species. This study provides a methodology and the correlation between geometrical parameters and eggshell qualities, and between geometrical parameters and organic matrix components in calcified shells., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Several studies have uncovered a highly heterogeneous landscape of genetic differentiation across the genomes of closely related species. Specifically, genetic differentiation is often concentrated in particular genomic regions ("islands of differentiation") that might contain barrier loci contributing to reproductive isolation, whereas the rest of the genome is homogenized by introgression. Alternatively, linked selection can produce differentiation islands in allopatry without introgression. We explored the influence of introgression on the landscape of genetic differentiation in two hybridizing goose taxa: the Taiga Bean Goose (Anser fabalis) and the Tundra Bean Goose (A. serrirostris). We re-sequenced the whole genomes of 18 individuals (9 of each taxon) and, using a combination of population genomic summary statistics and demographic modeling, we reconstructed the evolutionary history of these birds. Next, we quantified the impact of introgression on the build-up and maintenance of genetic differentiation. We found evidence for a scenario of allopatric divergence (about 2.5 million years ago) followed by recent secondary contact (about 60,000 years ago). Subsequent introgression events led to high levels of gene flow, mainly from the Tundra Bean Goose into the Taiga Bean Goose. This scenario resulted in a largely undifferentiated genomic landscape (genome-wide F ST  = 0.033) with a few notable differentiation peaks that were scattered across chromosomes. The summary statistics indicated that some peaks might contain barrier loci while others arose in allopatry through linked selection. Finally, based on the low genetic differentiation, considerable morphological variation and incomplete reproductive isolation, we argue that the Taiga and the Tundra Bean Goose should be treated as subspecies.

1. Adipocyte fatty acid binding protein (A-FABP) plays a key role in fatty acid uptake and intracellular transport. The objective of the present study was to identify and characterise the A-FABP gene in Xupu goose.2. The full-length cDNA of goose A-FABP gene was cloned from the liver tissue using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The distribution of the goose A-FABP in different tissues was determined by quantitative real-time PCR (qRT-PCR).3. The results showed that the full-length cDNA sequence of goose A-FABP was 657 bp, containing a 5'-UTR of 52 bp, a 3'-UTR of 206 bp and an open reading frame (ORF) of 399 bp, which encoded a polypeptide of 132 amino acids (AA).4. The AA sequence of goose A-FABP showed 76.52%, 75.00%, 93.18% and 99.24% identities with previously described homologues from humans ( Homo sapiens ), mouse ( Mus musculus ), chicken ( Gallus gallus ), and duck ( Anas platyrhynchos ), respectively, and phylogenetic analysis revealed a close relationship among them. The transcript of Xupu goose A-FABP was ubiquitously expressed in all tested tissues, and showed a high-level expression in abdominal fat, sebum and liver.5. A significant positive correlation was identified between A-FABP mRNA abundance in the three adipose tissues and liver weight, ratio of liver to body weight, TG content, and VLDL concentration in the plasma of Xupu goose. A significant negative correlation was observed between the mRNA level of A-FABP and HDL concentration in the plasma of Xupu goose.6. These findings provide a foundation for further research on the function and mechanism of A-FABP in the fat deposition process.

Dongting Lake is the second largest freshwater lake in China and is one of the globally important wintering sites for migratory waterbirds in the East Asian-Australasian Flyway. Crucial sites and environmental variables for wintering migratory waterbirds are of great concern in the Dongting Lake wetlands. In this research, based on annual (2003/2004-2016/2017) waterbird and habitat census data, we recognized the crucial sites for waterbirds during wintering seasons by comparing the difference of waterbird populations at the community, foraging guild and species levels in different natural wetlands within East Dongting Lake, and then identified the crucial environmental variables affecting waterbird distributions by analyzing the relationship between waterbird populations and the environmental variables, including vegetation area, mudflat area, water area with the depth of 0-20 cm, water area with the depth of 20-50 cm, water area with the depth of 50-100 cm, water area with the depth >100 cm, growth status of vegetation (Min, Mean and Max NDVI), and the human disturbance. Results indicated that five natural wetlands, i.e., Daxiaoxi, Chunfeng, Baihu lakes, Dingzi dyke and Tanjiaweizi, were recognized as the crucial wintering sites for migratory waterbirds in the East Dongting Lake. Among the ten selected environmental variables, water areas with the depth of 0-20 cm, 20-50 cm and >100 cm, human disturbance, Min and Mean NDVIs were identified as the crucial environmental variables overall. Waterbirds at different levels exhibited significant linear relationship with certain environmental variables, with the exception of Bean goose and Lesser White-fronted goose at the species level, which showed Gaussian distribution with changes in mean NDVI. The crucial environmental variables appeared to be foraging guild- and species-specific. These findings provide significant information for managers to understand the differences of wetlands and waterbird populations within East Dongting Lake, and to make more targeted conservation efforts., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this study, we characterized for the first time the gut microbiota of Greylag geese (Anser anser) using high-throughput 16S rRNA gene sequencing technology. The results showed that the phyla Firmicutes (78.55%), Fusobacteria (9.38%), Proteobacteria (7.55%), Bacteroidetes (1.82%), Cyanobacteria (1.44%), and Actinobacteria (0.61%) dominated the gut microbial communities in the Greylag geese. Then, the variations of gut microbial community structures and functions among the three geese species, Greylag geese, Bar-headed geese (Anser indicus), and Swan geese (Anser cygnoides), were explored. The greatest gut microbial diversity was found in Bar-headed geese group, while other two groups had the least. The dominant bacterial phyla across all samples were Firmicutes and Proteobacteria, but several characteristic bacterial phyla and genera associated with each group were also detected. At all taxonomic levels, the microbial community structure of Swan geese was different from those of Greylag geese and Bar-headed geese, whereas the latter two groups were less different. Functional KEGG categories and pathways associated with carbohydrate metabolism, energy metabolism, and amino acid metabolism were differentially expressed among different geese species. Taken together, this study could provide valuable information to the vast, and yet little explored, research field of wild birds gut microbiome., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

During the adaptive evolution of a particular trait, some selectively fixed mutations may be directly causative and others may be purely compensatory. The relative contribution of these two classes of mutation to adaptive phenotypic evolution depends on the form and prevalence of mutational pleiotropy. To investigate the nature of adaptive substitutions and their pleiotropic effects, we used a protein engineering approach to characterize the molecular basis of hemoglobin (Hb) adaptation in the high-flying bar-headed goose (Anser indicus), a hypoxia-tolerant species renowned for its trans-Himalayan migratory flights. To test the effects of observed substitutions on evolutionarily relevant genetic backgrounds, we synthesized all possible genotypic intermediates in the line of descent connecting the wildtype bar-headed goose genotype with the most recent common ancestor of bar-headed goose and its lowland relatives. Site-directed mutagenesis experiments revealed one major-effect mutation that significantly increased Hb-O2 affinity on all possible genetic backgrounds. Two other mutations exhibited smaller average effect sizes and less additivity across backgrounds. One of the latter mutations produced a concomitant increase in the autoxidation rate, a deleterious side-effect that was fully compensated by a second-site mutation at a spatially proximal residue. The experiments revealed three key insights: (i) subtle, localized structural changes can produce large functional effects; (ii) relative effect sizes of function-altering mutations may depend on the sequential order in which they occur; and (iii) compensation of deleterious pleiotropic effects may play an important role in the adaptive evolution of protein function.

Background: The impacts of hybridization on the process of speciation are manifold, leading to distinct patterns across the genome. Genetic differentiation accumulates in certain genomic regions, while divergence is hampered in other regions by homogenizing gene flow, resulting in a heterogeneous genomic landscape. A consequence of this heterogeneity is that genomes are mosaics of different gene histories that can be compared to unravel complex speciation and hybridization events. However, incomplete lineage sorting (often the outcome of rapid speciation) can result in similar patterns. New statistical techniques, such as the D-statistic and hybridization networks, can be applied to disentangle the contributions of hybridization and incomplete lineage sorting. We unravel patterns of hybridization and incomplete lineage sorting during and after the diversification of the True Geese (family Anatidae, tribe Anserini, genera Anser and Branta) using an exon-based hybridization network approach and taking advantage of discordant gene tree histories by re-sequencing all taxa of this clade. In addition, we determine the timing of introgression and reconstruct historical effective population sizes for all goose species to infer which demographic or biogeographic factors might explain the observed patterns of introgression., Results: We find indications for ancient interspecific gene flow during the diversification of the True Geese and were able to pinpoint several putative hybridization events. Specifically, in the genus Branta, both the ancestor of the White-cheeked Geese (Hawaiian Goose, Canada Goose, Cackling Goose and Barnacle Goose) and the ancestor of the Brent Goose hybridized with Red-breasted Goose. One hybridization network suggests a hybrid origin for the Red-breasted Goose, but this scenario seems unlikely and it not supported by the D-statistic analysis. The complex, highly reticulated evolutionary history of the genus Anser hampered the estimation of ancient hybridization events by means of hybridization networks. The reconstruction of historical effective population sizes shows that most species showed a steady increase during the Pliocene and Pleistocene. These large effective population sizes might have facilitated contact between diverging goose species, resulting in the establishment of hybrid zones and consequent gene flow., Conclusions: Our analyses suggest that the evolutionary history of the True Geese is influenced by introgressive hybridization. The approach that we have used, based on genome-wide phylogenetic incongruence and network analyses, will be a useful procedure to reconstruct the complex evolutionary histories of many naturally hybridizing species groups.

Transmembrane protein 8C (Tmem8C) is a muscle-specific membrane protein that controls myoblast fusion, which is essential for the formation of multinucleated muscle fibres. As most of the birds can fly, they have enormous requirement for the muscle, but there are only a few studies of Tmem8C in birds. In this study, we obtained the coding sequence (CDS) of Tmem8C in goose, predicted miRNAs that can act on the 3'UTR, analysed expression profiles of this gene in breast and leg muscles (BM and LM) during the embryonic period and neonatal stages, and identified miRNAs that might affect the targeted gene. The results revealed a high homology between Tmem8C in goose and other animals (indicated by sequence comparisons and phylogenetic trees), some conservative characteristics (e.g., six transmembrane domains and two E-boxes in the 5'UTR might be the potential binding sites of muscle regulatory factors (MRFs)), and the d N /d S ratio indicated purifying selection acting on this gene, facilitating conservatism in vertebrates. Q-PCR indicated Tmem8C had a peak expression pattern, reaching its highest expression levels in stage E15 in LM and E19 in BM, and then dropping transiently in E23 (P < 0.05). We examined 13 candidate miRNAs, and negative relationships were detected both in BM and LM (mir-125b-5p, mir-15a, mir-16-1 and mir-n23). Notably, mir-16-1 significantly decreased luciferase activity in dual luciferase reporter gene (LRG) assay, suggesting that it can be identified as potential factors affecting Tmem8C. This study investigated Tmem8C in water bird for the first time, and provided useful information about this gene and its candidate miRNAs in goose.

2'-5'-oligoadenylate synthetase-like (OASL) is a kind of antiviral protein induced by interferons (IFNs), which plays an important role in the IFNs-mediated antiviral signaling pathway. In this study, we cloned and identified OASL in the Chinese goose for the first time. Goose 2'-5'-oligoadenylate synthetase-like (goOASL), including an ORF of 1527bp, encoding a protein of 508 amino acids. GoOASL protein contains 3 conserved motifs: nucleotidyltransferase (NTase) domain, 2'-5'-oligoadenylate synthetase (OAS) domain, and 2 ubiquitin-like (UBL) repeats. The tissue distribution profile of goOASL in 2-week-old gosling and adult goose were identified by Real-Time quantitative PCR, which revealed that the highest level of goOASL mRNA transcription was detected in the blood of adult goose and gosling. The mRNA transcription level of goOASL was upregulated in all tested tissues of duck Tembusu virus (DTMUV)-infected 3-day-old goslings, compared with control groups. Furthermore, using the stimulus Poly(I: C), ODN2006, R848, and lipopolysaccharide (LPS) as well as the viral pathogens DTMUV, H9N2 avian influenza virus (AIV), and gosling plague virus (GPV) to treat goose peripheral blood mononuclear cells (PBMCs) for 6 h, goOASL transcripts level was significantly upregulated in all treated groups. To further investigate the antiviral activity of goOASL, pcDNA3.1(+)-goOASL-His plasmid was constructed, and goOASL was expressed by the goose embryo fibroblast cells (GEFs) transfected with pcDNA3.1(+)-goOASL-His. Our research data suggested that Newcastle disease virus (NDV) replication (viral copies and viral titer) in GEFs was significantly reduced by the overexpression of goOASL protein. These data were meaningful for the antiviral immunity research of goose and shed light on the future prevention of NDV in fowl.

Phylogenetic incongruence can be caused by analytical shortcomings or can be the result of biological processes, such as hybridization, incomplete lineage sorting and gene duplication. Differentiation between these causes of incongruence is essential to unravel complex speciation and diversification events. The phylogeny of the True Geese (tribe Anserini, Anatidae, Anseriformes) was, until now, contentious, i.e., the phylogenetic relationships and the timing of divergence between the different goose species could not be fully resolved. We sequenced nineteen goose genomes (representing seventeen species of which three subspecies of the Brent Goose, Branta bernicla) and used an exon-based phylogenomic approach (41,736 exons, representing 5887 genes) to unravel the evolutionary history of this bird group. We thereby provide general guidance on the combination of whole genome evolutionary analyses and analytical tools for such cases where previous attempts to resolve the phylogenetic history of several taxa could not be unravelled. Identical topologies were obtained using either a concatenation (based upon an alignment of 6,630,626 base pairs) or a coalescent-based consensus method. Two major lineages, corresponding to the genera Anser and Branta, were strongly supported. Within the Branta lineage, the White-cheeked Geese form a well-supported sub-lineage that is sister to the Red-breasted Goose (Branta ruficollis). In addition, two main clades of Anser species could be identified, the White Geese and the Grey Geese. The results from the consensus method suggest that the diversification of the genus Anser is heavily influenced by rapid speciation and by hybridization, which may explain the failure of previous studies to resolve the phylogenetic relationships within this genus. The majority of speciation events took place in the late Pliocene and early Pleistocene (between 4 and 2millionyears ago), conceivably driven by a global cooling trend that led to the establishment of a circumpolar tundra belt and the emergence of temperate grasslands. Our approach will be a fruitful strategy for resolving many other complex evolutionary histories at the level of genera, species, and subspecies., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Mothers against decapentaplegic homolog 4 (SMAD4) is an important protein in animal reproduction. It plays pivotal roles in cellular pathways, including apoptosis. The expression profile of the SMAD4 gene in goose ovarian follicles has not been reported. In this study, the SMAD4 coding sequence was cloned from the Yangzhou goose. A phylogenetic analysis was performed and mRNA expression was examined in various tissues using quantitative real-time PCR. An alternative splice form of SMAD4, SMAD4-b having 1656 bp, was identified. SMAD4-a mRNA was widely expressed in various healthy tissues, whereas SMAD4-b was very weakly expressed. SMAD4 mRNA in the ovary and oviduct was significantly higher than that in the pituitary and hypothalamus. SMAD4 mRNA expression analysis in hierarchical follicles showed that the level of SMAD4 mRNA was higher in large white follicles and post-ovulatory follicles than in the other follicles. The results indicate that SMAD4 might be involved in the recruitment of hierarchical follicles.

In this study, we cloned and sequenced the complete mitochondrial DNAs of Chinese goose, Anser cygnoides populations from three different areas of Hunan province in China. The Anser cygnoides breed Wugangtong white goose (WGTW) sample and Wugangtong grey goose sample (WGTG) were taken from the Wugang county of Shaoyang city, the Anser cygnoides breed Xupu goose (XP) sample was taken from the Xupu county of Huaihua city, and the Anser cygnoides breed Yanling white goose (YLW) sample was taken from the Yanling county of Zhuzhou city. The organization of the four Anser cygnoides breeds mitochondrial genomes was similar. Phylogenetic analyses using N-J computational algorithms showed that the analyzed species are divided into four major clades: Anatinae, Anserinae, Dendrocygninae and Anseranatidae. It was noted that Wugangtong white goose, Yanling white goose and Xupu goose have highly similar phylogenetic relationship.

In this study, we undertook the first complete the Swan Goose (Anser cygnoides L.) mitochondrial genome. The total length of the mitogenome is 16,739 bp. It contains the typical structure, including 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one D-loop region. The overall composition of the mitogenome is A (29.2%), G (15.8%), C (32.8%), and T (22.2%). Besides, the base preference of AT was not determined. Twenty-two kinds of tRNA were all typically cloverleaf structures. According to the phylogenetic analysis, A. cygnoides L. has a closer relationship with Anser anser.

The ornithine decarboxylase antizyme 2 (OAZ2) gene is a member of the antizyme gene family. Antizymes play pivotal roles in various cellular pathways, including polyamine anabolism and apoptosis. The molecular structure and expression profile of the OAZ2 in goose ovarian follicles have not been reported. In this study, the OAZ2 cDNA sequence of the Sichuan white goose was cloned (Anser cygnoides), and phylogenetic and structural analyses of the OAZ2 were performed. The expression profiling of OAZ2 mRNA in goose ovarian follicles was examined using quantitative real-time PCR. The sequence analysis showed that the 756 bp OAZ2 sequence contained two overlapping open reading frames (ORF). ORF1 was 99 bp in length, and encoded a 32 aa polypeptide. ORF2 was 477 bp in length, and encoded a 158 aa polypeptide. The frameshift site that initiates the translation of ORF2 was located at nucleotide position 97 in the OAZ2. The analysis of OAZ2 mRNA expression in hierarchical follicles showed that the level of OAZ2 mRNA was higher in the SWF and F2 follicular stages than that in the ovarian stroma (P<0.05). The lowest level of OAZ2 expression was detected in the ovarian stroma. These results suggest that the highly conserved frameshift region plays an important role in sustaining the function of OAZs. Furthermore, the significantly higher level of OAZ2 mRNA in the SWF stage indicates that OAZ2 may be involved in recruiting hierarchical follicles. Our results also suggest that OAZ2 may augment the effects of OAZ1 in follicle development., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Dopamine D2 receptor (DRD2) gene, a member of the dopamine receptors gene family, has been studied as a candidate gene for broodiness due to its special effects on avian prolactin secretion. Here, the genomic DNA and cDNA sequences of goose (Anser cygnoides) DRD2 gene were cloned and characterized for the first time. The goose DRD2 cDNA is 1353bp in length and encodes a protein of 450 amino acids. The length of goose DRD2 genomic DNA is 8350bp, including seven exons and six introns. We identified four goose DRD2 variants, which were generated due to alternative splicing. Bioinformatics analysis indicates that all the deduced DRD2 amino acid sequences contain seven putative transmembrane domains and four potential N-glycosylation sites. A phylogenetic tree based on amino acid sequences displays that the goose DRD2 protein is closely related to those of avian species. Semi-quantitative RT-PCR analysis demonstrates that the DRD2-1, DRD2-2 and DRD2-4 transcripts are differentially expressed in the pituitary, ovary, hypothalamus, as well as in the kidney, whereas the DRD2-3 transcript is widely expressed in all the examined tissues at different levels. Meanwhile, 54 single nucleotide polymorphisms (SNPs) and 4 insert-deletion (indel) variations were identified in the coding region and partial intron region of the goose DRD2 gene. Those findings will help us gain insight into the functions of the DRD2 gene in geese., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

The ENO1 gene encodes a multifunctional enzyme that has been identified as a key component of the glycolytic pathway. Our previous studies demonstrated that ENO1 gene expression was higher in the ovaries of laying geese compared with prelaying geese. However, the molecular characterisation and expression profiling of the ENO1 gene in geese tissues and ovarian follicles remain to be determined. In this study, ENO1 cDNA (1,445 bp long) of the Sichuan white goose was cloned and characterised. The ORF of ENO1 cDNA is 1,305 bp in length and encodes a 434 amino acid protein with a molecular weight of 47.27 kDa. ENO1 expression in all of the examined tissues was the highest in spleen and the lowest in breast muscle. High expression of ENO1 appeared in the kidney, liver, adrenal gland, and retina. With increasing follicle growth, ENO1 gene expression began to decrease from the small white follicle to F5, which was followed by a sharp increase in expression in F4 and then a gradual decrease in expression from F3 to F1. Furthermore, in the postovulatory follicles (POF), the levels of ENO1 gene expression decreased gradually from POF1 to POF4. In conclusion, the ENO1 transcript was widely distributed in various tissues of the Sichuan white goose, but ENO1 expression was tissue-specific. Furthermore, the results of the ENO1 expression profiling of ovarian follicles suggest that ENO1 may play an important dual role in the progress of follicular development, where ENO1 acts as a glycolytic enzyme and also mediates apoptosis.

Mitochondrial DNA plays an important role in living organisms, and has been used as a powerful molecular marker in a variety of evolutionary studies. In this study, we determined the complete mtDNA of Bean goose (Anser fabalis), which is 16,688 bp long and contains 13 protein-coding genes, 2 rRNAs, 22 tRNAs and a control region. The arrangement is similar to that of typical Anseriform species. All protein-coding genes, except for Cyt b, ND5, COI, and COII, start with an ATG codon. The ATG start codon is also generally observed in the 12 other Anseriform species, including 2 Anser species, with sequenced mitochondrial genomes. TAA is the most frequent stop codon, one of three-TAA, TAG, and T- -commonly observed in Anseriformes. All tRNAs could be folded into canonical cloverleaf secondary structures except for tRNA(Ser)(AGY) and tRNA(Leu)(CUN), which are missing the dihydrouridine (DHU) arm. The control region of Bean goose mtDNA, with some conserved sequence boxes, such as F, E, D, and C, identified in its central domain. Phylogenetic analysis of complete mtDNA data for 13 Anseriform species supports the classification of them into four major branches: Anatinae, Anserinae, Dendrocygninae and Anseranatidae. Phylogenetic analyses were also conducted on 36 Anseriform birds using combined Cyt b, ND2, and COI sequences. The results clearly support the genus Somateria as an independent lineage classified in its own tribe, the Somaterini. Recovered topologies from both complete mtDNA and combined DNA sequences strongly indicate that Dendrocygninae is an independent subfamily within the family Anatidae and Anseranatidae represents an independent family. Based on the results of this study, we conclude that combining ND2, Cyt b, and COI sequence data is a workable solution at present for resolving phylogenetic relationships among Anseriform species in the absence of sufficient complete mtDNA data.

Migratory birds are of particular interest for population genetics because of the high connectivity between habitats and populations. A high degree of connectivity requires using many genetic markers to achieve the required statistical power, and a genome wide SNP set can fit this purpose. Here we present the development of a genome wide SNP set for the Barnacle Goose Branta leucopsis, a model species for the study of bird migration. We used the genome of a different waterfowl species, Mallard Anas platyrhynchos, as a reference to align Barnacle Goose second generation sequence reads from an RRL library and detected 2188 SNPs genome wide. Furthermore, we used chimeric flanking sequences, merged from both Mallard and Barnacle Goose DNA sequence information, to create primers for validation by genotyping. Validation with a 384 SNP genotyping set resulted in 374 (97%) successfully typed SNPs in the assay, of which 358 (96%) were polymorphic. Additionally, we validated our SNPs on relatively old (30 years) museum samples, which resulted in a success rate of at least 80%. This shows that museum samples could be used in standard SNP genotyping assays. Our study also shows that the genome of a related species can be used as reference to detect genome wide SNPs in birds, because genomes of birds are highly conserved. This is illustrated by the use of chimeric flanking sequences, which showed that the incorporation of flanking nucleotides from Mallard into Barnacle Goose sequences lead to equal genotyping performance when compared to flanking sequences solely composed of Barnacle Goose sequence.

The aim of the research was to compare the karyotypes of two goose species: the European domestic goose and the Asian goose on the basis of the karyotype of their interspecific cross-breed, using the RBG chromosome staining technique. The karyotype standard for Anseriformes has not been determined yet. The RBG technique is considered as one of the standard methods for analysing chromosomes. It is a dynamic method. The R bands appear during the cell growth cycle in the early S phase. The formation of the characteristic band configuration for each chromosome facilitates chromosome segregation and analysis. The mitotic chromosomes for experiments were obtained from an in vitro blood lymphocyte culture and stained according to the RBG technique. The first eight largest autosome pairs and the ZW sex chromosomes were analysed. No differences were found between the band patterns of the analysed chromosomes, except for the fourth autosome pair.

Bar-headed geese (Anser indicus) fly at up to 9,000 m elevation during their migration over the Himalayas, sustaining high metabolic rates in the severe hypoxia at these altitudes. We investigated the evolution of cardiac energy metabolism and O(2) transport in this species to better understand the molecular and physiological mechanisms of high-altitude adaptation. Compared with low-altitude geese (pink-footed geese and barnacle geese), bar-headed geese had larger lungs and higher capillary densities in the left ventricle of the heart, both of which should improve O(2) diffusion during hypoxia. Although myoglobin abundance and the activities of many metabolic enzymes (carnitine palmitoyltransferase, citrate synthase, 3-hydroxyacyl-coA dehydrogenase, lactate dehydrogenase, and pyruvate kinase) showed only minor variation between species, bar-headed geese had a striking alteration in the kinetics of cytochrome c oxidase (COX), the heteromeric enzyme that catalyzes O(2) reduction in oxidative phosphorylation. This was reflected by a lower maximum catalytic activity and a higher affinity for reduced cytochrome c. There were small differences between species in messenger RNA and protein expression of COX subunits 3 and 4, but these were inconsistent with the divergence in enzyme kinetics. However, the COX3 gene of bar-headed geese contained a nonsynonymous substitution at a site that is otherwise conserved across vertebrates and resulted in a major functional change of amino acid class (Trp-116 → Arg). This mutation was predicted by structural modeling to alter the interaction between COX3 and COX1. Adaptations in mitochondrial enzyme kinetics and O(2) transport capacity may therefore contribute to the exceptional ability of bar-headed geese to fly high.

Cultural transmission is thought to be a mechanism by which migratory animals settle into habitats, but little evidence exists in wild populations because of the difficulty of following individuals over successive generations and wide geographical distances. Cultural inheritance of migration routes represents a mechanism whereby geographical isolation can arise between separate groups and could constrain individuals to potentially suboptimal sites within their range. Conversely, adopting the parental migratory route in adult life, rather than dispersing randomly, may increase an individual's reproductive success because that strategy has already been proven to allow successful breeding. We combined a pedigree of related light-bellied Brent geese (Branta bernicla hrota) with 6 years of observations of marked birds to calculate the dispersal distances of adult offspring from their parents in both Ireland and Iceland. In both countries, the majority of offspring were found to recruit into or near their parental sites, indicating migratory connectivity in the flyway. Despite this kin structure, we found no evidence of genetic differentiation using genotype data from 1127 individuals across 15 microsatellite loci. We suggest that the existence of migratory connectivity of subpopulations is far more common than previous research indicates and that cultural information may play an important role in structuring reproductive isolation among them., (© 2010 Blackwell Publishing Ltd.)

Two species of waterfowl living at high altitude provide a prominent example of parallel adaptation at the molecular level. The bar-headed goose (Anser indicus) breeds at high elevations in central Asia and migrates across the Himalayas, where the partial pressure of oxygen (O(2)) is one-third of sea level. In South America, the distantly related Andean goose (Chloephaga melanoptera) is endemic to the high Andes. Both species exhibit increased blood-O(2) affinity, which has been attributed to the effects of single amino acid substitutions in the major hemoglobin. Here we present phylogenetic analyses of the swans and geese (Anserinae) and South American sheldgeese (Anatinae) using the three genes that encode the major (HbA) and minor (HbD) hemoglobin isoforms. We sought to determine whether two amino acid substitutions that have been the focus of extensive biochemical analysis (Ala-alpha(A)119 and Ser-beta(A)55) are uniquely derived in bar-headed goose and Andean goose, respectively, and to examine evidence of molecular adaptation at other positions in hemoglobin genes by comparing these two high-altitude taxa to their closest relatives. Bayesian analysis of the alpha(A)-, alpha(D)-, and beta(A)-subunit genes produced well-resolved phylogenies, with high posterior probabilities and bootstrap values for most genera. The bar-headed goose is likely sister to all other Anser species. Andean goose, the sole highland representative of the South American sheldgeese is either sister to the other Chloephaga species or sister to Neochen. In the bar-headed goose, four derived substitutions were observed in HbA (alpha(A)12, 18, 63, 119) and two in HbD (alpha(D)2, 47). Four derived substitutions in Andean goose include three in HbA (alpha(A)8, 77; beta(A)86) and two in HbD (alpha(D)9; beta(A)86). Considering both highland species, four substitutions (Ala-alpha(A)8, Ala-alpha(A)12, Ser-alpha(A)18, Leu-alpha(D)9) were located at adjacent positions on the A helix (or AB corner) of the alpha-chains, three others (Thr-alpha(A)77, Ser-beta(A)86, Ser-alpha(D)2) were in close proximity to inositolpentaphosphate (IP(5)) binding sites, and Ala-alpha(A)119 occurred at an alphabeta intersubunit contact. Ser-beta(A)55, which is involved in the same alphabeta intersubunit contact and was previously shown to increase Hb-O(2) affinity, is not unique to Andean goose, but is a synapomorphy of the South American sheldgeese, a clade of predominantly lowland waterfowl. Our findings illustrate the importance of understanding phylogenetic relationships and polarity of character-state changes when making inferences about adaptive evolution., (Copyright 2010 Elsevier Inc. All rights reserved.)

In order to understand the variations of genomic organization of the major histocompatibility complex (MHC) and provide data for the studies on disease resistance of avian species, the MHC class II polymorphism in Chinese Z-goose was investigated for the first time in the present study. Eight alleles, which probably came from different loci, were found in six different geese with only one obvious band in the restriction fragment length polymorphism data. The numbers of nonsynonymous substitutions (dN) in peptide binding region of exon 2 were higher than that of synonymous substitutions (dS), and no stop codons or frameshift mutations were found in this region, indicating that balance selection was in operation, and the sequences are not likely to be pseudogenes. In addition, we successfully obtained five different long MHC class II fragments (about 1,162 bp) in six geese and found that the length of intron 1 was longer than that in chicken and some other birds, but intron 2 seemed to be intermediate in length. The phylogenetic tree appeared to branch in an order consistent with accepted evolutionary pathway.

The bean goose Anser fabalis and the pink-footed goose A. brachyrhynchus breed in the tundra and taiga zones of Eurasia and eastern Greenland, and the taxonomy of the group based on morphology has been controversial. We investigated the phylogenetic relationships within the bean goose-the pink-footed goose complex using mitochondrial control region sequences of 199 individuals collected from the breeding areas in the Palaearctic and Eastern Nearctic. We found three mitochondrial clades geographically distributed to (1) Greenland, Iceland and Svalbard (A. brachyrhynchus), (2) the eastern taiga zone (former subspecies A. fabalis middendorffii), and (3) the western taiga and the tundra zone (subspecies A. fabalisrossicus, serrirostris and fabalis). MtDNA phylogeny suggests that morphological affinities between the taxa, e.g. in the bill structure, result from convergent evolution due to adaptation to similar habitats. Although a latitudinal cline in morphology was observed, clear phylogenetic discontinuities exist in the taiga and tundra zones supporting a species status for brachyrhynchus and middendorffii.

The genetic diversity of six goose breeds (White Goose, Zi Goose, Huoyan Goose, Wanxi Goose, Rhin, Landoise) was analyzed using microsatellite markers. Heterozygosity(H), polymorphism information content (PIC) and genetic distances were calculated for each breed based on the allele frequency. Results showed that 7 microsatellite sites were highly polymorphic, and could be used as effective markers for analysis of genetic relationship among different goose breeds. The mean heterozygosityies of were between 0.6617 (Rhin) and 0.8814 (Zi goose), among six goose breeds, the lowest was Rhin goose (0.6617) and the highest was Zi goose (0.8814). The range of mean PIC was between 0.6145 and 0.7814, which was in the similar range as the mean heterozygosities. Based on the UPGMA cluster analysis results, six goose breeds were grouped into classes, White, Zi, Huoyan and Wanxi Goose in one class, and the foreign breeds of Rhin and Landoise goose in another class. These results indicated that the dendrogram obtain from genetic distance could be used to correctly reflect the phylogenetic relationship among the six goose breeds, suggesting that microsatellite DNA marker is a useful tool to determine the genetic diversity in closely related breeds.

A West Nile virus (WNV) outbreak occurred at a commercial waterfowl operation in Wisconsin in 2005. Retrospective analysis of dead and live birds was conducted. WNV was detected by PCR in 84.1% of 88 dead birds; neutralizing antibodies were found in 14 of 30 randomly sampled asymptomatic or recovered birds.

It has generally been assumed, based on morphology, that Chinese domestic goose breeds were derived from the swan goose (Anser cygnoides) and that European and American breeds were derived from the graylag goose (Anser anser). To test the validity of this assumption, we investigated the mtDNA cleavage patterns of 16 Chinese breeds and 2 European breeds as well as hybrids produced between a Chinese breed and a European breed. After 224 mtDNAs, isolated from the Chinese and European breeds, were digested by 19 restriction endonucleases, variations of the cleavage patterns were observed for four enzymes (EcoRV, HaeII, HincII, and KpnI). All Chinese breeds and their maternal hybrids except the Yili breed showed an identical haplotype, named haplotype I or the Chinese haplotype; the European breeds and the Yili breed showed another haplotype, named haplotype II or the western haplotype. None of the haplotype found in the Chinese type was detectable in the western type and vice versa. The two haplotypes were found to differ from each other at 8.0% of the sites surveyed and with a 0.72% sequence divergence. Using 2% substitution per million years calibrated from the genera Anser and Branta, the two domestic geese haplotypes were estimated to have diverged approximately 360,000 years ago, well outside the 3000-6000 years in domestic history. Our findings provide the first molecular genetic evidence to support the dual origin assumption of domestic geese in the world. Meanwhile, the four mtDNA restriction fragment length polymorphisms can be used as maternal genetic markers to distinguish the two types of domestic geese.

The 1 042 bp control region of mitochondrial DNA from 84 geese of 15 domestic goose breeds was sequenced and genetic differentiation was analysed. Results showed that the interpopulation nucleotide divergence was highest (3.805% -4.067%) between Yili and the other 14 breeds. The average nucleotide diversity variation within different domestic breeds was 0 - 0.116%. Excluding the Yili, the interpopulation nucleotide divergence between Huoyan and the remaining breeds, was 0.211% - 0.272%, which was significantly higher than that between any other two breeds (0 -0.094%). During the formation of domestic breeds in China,there is an association between the genetic differentiation of domestic geese and their geographic distribution. The divergence time of Huoyan breed was relatively earlier and genetic drift may have been the main factor to affect the genetic differentiation of the Huoyan breed (Nm = 0.02 -0.54). On the other hand, gene flow is the main reason for the lack of a clear differentiation among the remaining 13 Chinese domestic geese breeds (Nm = 12.0 - 65.33).

The mitochondrial cytochrome b (cyt b) gene of 17 breeds of domestic goose (2 in Europe and 15 in China) was sequenced and compared with that of the representative of wild species Anser albifrons. Sequence analysis revealed that thirty-one variable sites and 4 different haplotypes were found among the 45 sequences examined, and nucleotide diversity and haplotype diversity were 0.0068 and 0.45, respectively. Mutations of insertion/deletion were not found. Across all sites,the abundance of G was low (14.2%), whereas the percentages of A, T, and C were quite similar among three Anser goose species. The frequency of guanine differs greatly among the three codon positions. Compositional bias is smaller at first and second positions (0.057 and 0.223) than at third positions (0.492), the probability of transition was higher than that of tranversion (Ts/Tv=9.5-19), there was the highest number of transition in the third codon. The phylogenetic analysis support the hypothesis of dual origin of domestic geese.

Population structure and phylogeography of the pink-footed goose, Anser brachyrhynchus Baillon 1833, was studied using mtDNA control region sequences (221 bp) from 142 individuals. Present breeding areas of the species in Greenland, Iceland, and Svalbard were largely covered by ice during the late Pleistocene. In pairwise comparisons phiST estimates showed significant differentiation among eastern and western populations, whereas sampling localities within both areas were not differentiated. The mtDNA data indicate that the populations have separated recently (less than 10 000 years ago) and present breeding areas were colonized from one refugial population. The levels of haplotype and nucleotide diversity were approximately five times higher for the eastern population compared to the western population and suggest that the latter was colonized by a subset of eastern birds. Time to the most recent common ancestor of the species is 32 000-46 000 years, i.e. the present mtDNA variation of the pink-footed goose has accumulated during the last 0.1 My. Estimates of the long-term female effective population size (5400-7700 for the eastern population) imply that the refugial population of the pink-footed goose has been large. Tundra habitats were more extensive in cold periods of the late Pleistocene than today and may have sustained population sizes that allowed the accumulation of extant genetic polymorphism. It is not probable that the postulated small refugial areas in the high latitudes had a significant role in maintaining this diversity.

Phylogenetic analysis of 1.35 kb of mtDNA sequence from fossils revealed a previously unknown radiation of Hawaiian geese, of which only one representative remains alive (the endangered Hawaiian goose or nene, Branta sandvicensis). This radiation is nested phylogenetically within a living species, the Canada goose (Branta canadensis) and is related most closely to the large-bodied lineage within that species. The barnacle goose (Branta leucopsis) is also nested within the Canada goose species and is related most closely to the small-bodied lineage of Canada geese. The peripheral isolation of the barnacle goose in the Palearctic apparently allowed the evolution of its distinctive plumage pattern, whereas the two Nearctic lineages of Canada geese share a primitive plumage pattern. The Hawaiian lineage of Canada geese diverged more dramatically, splitting into at least three species that differ in body size, body proportions, and flight ability. One fossil species, limited to the island of Hawaii, was related closely to the nene but was over four times larger, flightless, heavy-bodied and had a much more robust cranium. Application of a rate calibration to levels of DNA divergence suggests that this species evolved on the island of Hawaii in less than 500,000 years. This date is consistent with the potassium/argon-based age of the island of Hawaii of 430,000-500,000 years. The giant Hawaii goose resembles the moa-nalos, a group of massive, extinct, flightless ducks that lived on older Hawaiian Islands and thus is an example of convergent evolution of similar morphologies in island ecosystems.

RAPD markers often primers were used to assess the polymorphism among pooled DNA of eight goose lines. The number of bands amplified by each primer ranged from 1 to 8, within a mean of 2.86. Some bands appeared specific for the line or genetic background. RAPD technique is an effective method for generating the polymorphic DNA marker in the goose. RAPD patterns from mixed DNA samples can reflect the genetic information of populations. The present study indicated that 10 generations selected for egg production and body weight under various pressure, resulted in genetic variation among goose lines as detected by RAPD. Selection for meat traits caused greater genetic diversity than selection for egg production.

Polymerase chain reaction (PCR) amplification of the nuclear 5S rDNA gene has been used for the identification of goose and mule duck foie gras. Two species-specific reverse primers were designed and used in a multiplex reaction, together with a forward universal primer, to amplify specific fragments of the 5S rDNA in each species. The different sizes of the species-specific amplicons, separated by agarose gel electrophoresis, allowed clear identification of goose and mule duck foie gras samples. This genetic marker can be useful for detecting fraudulent substitution of the duck liver for the more expensive goose liver.

Mitochondrial DNAs (mtDNAs) of 138 samples from 11 domestic goose breeds in China were investigated by digesting, with 19 restriction endonucleases. Of 19 enzymes used, seven (Bcl I, Dra I, Eco RV, Hae II, Hinc II, Kpn I, Sac I) detected polymorphic patterns. By combining 27 restriction morphs, 138 individuals were classified into 6 mtDNA haplotypes. Phylogenetic tree was constructed by using UPGMA. There was no shared haplotype between Yili breed and the other 10 breeds. Genetic distance and UPGMA tree also suggested that Yili breed and other breeds came from different ancestors. Yili breed originated from Anser anser and other 10 breeds originated from Anser cygnoides. Restriction morphs digested with 4 enzymes (EcoRV, Hae II, Hinc II and Kpn I) could be used as maternal genetic markers to distinguish the two types of domestic geese. Mitochondrial DNA polymorphism was observed in the ten breeds of Anser cygnoides. Nucleotide diversity (pi), genetic distance between the two types and the average genetic distance among the ten breeds were estimated to be 0.025%, 0.266%, 0.029%, respectively. The breeds with white plume were affected by founder effect when they were formed. Swan domestic geese, Anser cygnoides domesticus, in China might come from two different populations of Anser cygnoides at two different places.

1. Ovomucoids were purified from Muscovy duck, domestic duck and domestic goose. 2. Peptide maps of cyanogen bromide-cleaved ovomucoids from Muscovy duck and domestic duck were very similar to one another, but differed from that of goose. 3. Muscovy duck ovomucoid showed the same protease inhibitory pattern as ovomucoid from domestic duck, inhibiting trypsin in the molar ratio of 1:2 and chymotrypsin 1:1. 4. Inhibitory complexes could be detected between chymotrypsin and ovomucoid from both Muscovy and domestic duck, but not from goose, by using non-denaturing gels. 5. No complexes could be detected between DFP-inactivated chymotrypsin and any of the ovomucoids. 6. The results show that of ovomucoid from Muscovy duck more closely resembles that from domestic duck than goose.

An electrophoretical analysis of blood plasma proteins of eight Anser and two Branta species was performed. Ten polymorphic proteins in blood plasma pattern were distinguished and described: four prealbumin proteins, albumin, three postalbumin proteins, transferrin, and a single posttransferrin protein. Genus-specific and species-specific variants of Pr-1, Al, Pa-3, Pa-X, and Tf proteins were found. The species of Branta differed in Pr-1, Pa-3, Pa-X, and Tf loci. The Anser species differed, apparently, in allele frequencies of described gene loci. A single species-specific protein marker was found in swan geese only. The electrophoretic mobilities of Pr-1, TfB, and PtfA, B, and C were similar for several species of Anser and Branta genera.