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This study aimed to identify genes related to sheep growth, development and meat quality. Small-tailed Han sheep (STH), and small-tailed Han sheep and Suffolk crossbred F1 (STH×SFK), were selected to determine the growth performance, slaughter performance, and meat quality. The longissimus dorsi muscle was selected for transcriptome sequencing, and the target gene was screened based on bioinformatics analysis; real-time fluorescent quantitative PCR (RT-PCR) and western blotting (WB) were conducted to verify the target gene. Locations of genes in tissues were confirmed via immunofluorescence. The results showed that the pre-slaughter live weight, bust circumference, slaughter performance, and marbling score of the STH×SFK population were significantly higher than those of the STH population (P < 0.01). Sequencing results showed that 560 differentially expressed genes (DEGs) were identified in the STH×SFK population, of which 377 exhibited up-regulated and 183 exhibited down-regulated expression levels. GO annotation revealed that DEGs could be classified into 13 cell components, 10 molecular functions, and 22 biological processes. The KEGG enrichment analysis showed that DEGs were mainly enriched in the Rap1 signaling pathway, Ras signaling pathway, and other pathways related to growth and meat quality. Based on the GO and KEGG analyses, four candidate genes related to sheep growth and meat quality, namely myostain (MSTN), interferon-related developmental regulator 1 (IFRD1), peroxisome proliferator activator receptor delta (PPARD), and myosin light chain 2 (MLC2 or MYL2), were screened. The expression levels of genes and proteins were verified via RT-PCR and WB, and the results were consistent with the trend of transcriptome sequencing. Immunofluorescence results showed that IFRD1 was expressed in the cytoplasm and nucleus, and MYL2 was expressed in the cytoplasm. This study revealed the mechanism of gene regulation of sheep growth and development at the molecular level and provided a theoretical basis for studying sheep genetics and breeding.

Chinese cabbage is an important vegetable in Asia, and high-yielding hybrids are needed to cope with the growing demand. A comparative transcriptome profiling was conducted to reveal the differentially expressed genes (DEGs) associated with heterosis in two hybrids relative to their parents. Our data suggests that heterosis is underlined by a significant upregulation of gene expression. High expression of DEGs in glycolysis and photosynthesis pathways in hybrids depicted their relation with growth and hybrid vigor. Besides, DEGs related to auxin, abscisic acid, ethylene and gibberellin were identified, implying that these hormones may boost the mechanisms of growth and developmental processes in the hybrids. Furthermore, transcription factors, including bHLH, ERF, MYB and WRKY were predicted to regulate downstream genes linked to hybrid vigor. Collectively, the present study will be helpful for a better understanding of the regulation mechanisms of heterosis to aid cabbage yield improvement. • Transcriptional mechanisms of heterosis in Chinese cabbage was studied. • Heterosis is underlined by a significant upregulation of gene expression. • Heterosis is mainly associated with non-additive expression. • Glycolysis and photosynthesis pathways were altered in hybrids. • Phytohormones related genes play crucial role in heterosis. [ABSTRACT FROM AUTHOR]

Summary: The Tibetan chicken is a native Chinese breed that lives at high elevations and has adapted to the extreme environmental conditions of the Tibetan Plateau. However, its hypoxic adaptation at the gene expression level is unclear. Here, we sequenced nine lung transcriptomes of the Tibetan chicken at three developmental stages (5 and 42 weeks and 4.5 years). A total of 1.02 billion clean reads were obtained. We identified 16 012 mRNAs and 6898 lncRNAs. The expression of mRNA showed that nine samples were significantly divided into three clusters, with higher correlation and closer relationship between the 5 and 42 week groups. We identified 399 differentially expressed genes (DEGs) between the 5 and 42 week groups, 3532 DEGs between the 5 week and 4.5 year groups, and 3909 DEGs between the 42 week and 4.5 year groups. The up‐regulated DEGs in the 5 week group, compared with 42 week and 4.5 year groups, were enriched in GO terms associated with growth and development, whereas the up‐regulated DEGs in the 4.5 year group were mainly enriched in many metabolic‐related categories. Moreover, the enrichment results with up‐regulated DEGs in the 5 and/or 42 week groups, compared with the 4.5 year group, were associated with hypoxic adaptation, such as oxygen transport, oxygen binding and oxygen carrier activity, and calcium signaling pathway. In addition, we identified 978 high‐correlation lncRNA and protein‐coding gene pairs, and 524 significant neighboring protein‐coding genes were also DEGs. Our results provide new insights into gene expression of lung tissue in Tibetan chickens during the aging process. [ABSTRACT FROM AUTHOR]