ABSTRACT: Pseudotargeted metabolomics and metagenomics revealed the mechanism of different fattening strategies affecting the growth performance of yaks
Project description:Purpose: The goal of this study was to reveal epigenetic differences in the microRNA transcriptomes of two organs (heart and lung) between yak and cattle. Methods: Three unrelated 2-year old adult females for both of yaks and cattle (Luxi Huang cattle) were used in this study. Two of significant hypoxia-responsive tissues (heart and lung) were rapidly collected from each carcass, washed three times with physiological saline, immediately frozen in liquid nitrogen. All frozen samples were stored at –80 °C until RNA extraction.The total RNA were extracted with Trizol (Ambion, USA). NanoDrop ND-2000 spectrophotometer (Nano Drop, DE, USA) and Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA, USA) were used to monitor the concentration and integrity of RNA, respectively. In brief, several successive steps consist the Illumina sequencing. The small RNA with length of 14-40 nt were first purified by polyacrylamide gel electrophoresis (PAGE), and then specific adapters were ligated to the purified small RNA. The ligated RNA were reverse transcribed to cDNA libraries. Finally, each library were sequenced on Genome Analyzer. Results: We identified 808 widely-expressed conserved and 697 species-specific novel miRNAs in two species. In addition, although two organs showed similar high expression miRNAs, larger differentiation was present in lung than heart between two species. In addition, miRNAs with significantly differentiated patterns of expression in two organs exhibited obvious co-operation effect in high altitude adaptation in form of miRNA family and cluster. Functional analysis revealed that a large amount of differentially expressed miRNAs were enriched in hypoxia-related pathways, such as VEGF signaling pathway, HIF-1α signaling pathway, insulin signaling pathway, DNA damage response, apoptosis, fatty acid metabolism and glucose metabolism. These results suggested the diverse degrees of epigenetic variation in different tissues between yak and cattle, and revealed extensive roles of miRNAs in high altitude adaptation. Conclusions: In this study, we illustrated the differences in the microRNA transcriptomes level for heart and lung between yak and cattle, and suggested extensive roles of miRNAs in high altitude adaptation. The work performed here will provide a typical demonstration for future deciphering the mechanism of high altitude adaptation
Project description:Comparative study of growth performance, rumen fermentation, nutrient digestibility, and ruminal and fecal bacterial community between yaks and cattle-yaks raised by stall-feeding
Project description:Background and aimMitochondrial genome has aseries of characteristics such as simple structure, no recombination, maternalinheritance, stable structure, fast evolution rate, and high copy number. Moreover, it is easy to be sequenced,contains high-resolution phylogenetic information, and exists in a wide rangeof taxa. Therefore, it is widely used in the study of biological phylogeny. Atpresent, phylogenetic studies focus mainly on D-loop region, cytochrome b gene,and protein-coding sequence. Phylogenetic studies using the mitochondrialcomplete sequence are rarely reported in yak. Therefore, the present studyaimed to construct phylogenetic tree using yak mitochondrial complete sequenceand compare the subsequent results with previous findings obtained usingpartial sequences.ResultsComplete mitochondrial sequences of five yakpopulations from Qinghai and Xinjiang were obtained. The mitotype diversity ofthe five populations was Xueduo yak (0.992 ± 0.015), Pamir yak (0.990 ± 0.014),Yushu yak (0.963 ± 0.033), Qilian yak (0.948 ± 0.036), and Huanhu yak (0.905 ±0.048), which showed a higher mitotype diversity compared with other breeds fromthe previous reports, including Jiulong yak, Maiwa yak, Zhongdian yak, andTianzhu yak. A total of 78 mitotypes were obtained from 111 individuals. Amongthese, Yushu yak, Huanhu yak, Xueduo yak, and Qilian yak all shared mitotypes,but the Pamir yak did not share mitotypes with these four populations.Phylogenetic analysis showed that yak populations were separable into threedistinct branches. The analysis identified a new phylogenetic branch containingboth wild and domestic yaks. The 155 mitotypes found in 206 individuals weredivided into 3 haplogroups by mitotype clustering. Thehaplogroup was not associated with the geographical distribution of yaks. Theyaks in the same population or the same ecological environment were distributedin different haplogroups. Among the threehaplogroups, haplogroup A and haplogroup B showed a star-shaped distribution ofmitotypes. The central mitotypes were widely distributed and had a highfrequency.ConclusionsThegenetic diversity of yaks in Qinghai was high. Both domestic and wild yaks clusteredinto three branches.
Project description:As important livestock in Qinghai-Tibet Plateau, yak provides meat and other necessities for Tibetans living. Plateau yak has resistance to diseases and stress, yet is nearly unknown in the structure and expression mechanism of yak immunoglobulin loci. Based on the published immunoglobulin genes of bovids (cattle, sheep and goat), the genomic organization of the yak immunoglobulin heavy chain (IgH) and immunoglobulin light chain (IgL) were described. The assemblage diversity of IgH, Igλ and Igκ in yak was similar to that in bovids, and contributes little to the antibody lineage compared with that in humans and mice. Somatic hypermutation (SHM) had a greater effect on immunoglobulin diversity in yak than in goat and sheep, and in addition to the complementarity-determining region (CDR), some loci in the framework region (FR) also showed high frequency mutations. CDR3 diversity showed that immunological lineages in yak were overwhelmingly generated through linkage diversity in IgH rearrangements. The emergence of new high-throughput sequencing technologies and the yak whole genome (2019) publication have greatly improved our understanding of the immune response in yaks. We had a more comprehensive analysis of yak immunoglobulin expression diversity by PE300, which avoided the disadvantage of missing low-frequency recombination in traditional Sanger sequencing. In summary, we described the schematic structure of the genomic organization of yak IgH loci and IgL loci. The analysis of immunoglobulin expression diversity showed that yak made up for the deficiency of V(D)J recombinant diversity by junctional diversity and CDR3 diversity. In addition, yak, like cattle, also had the same ultra-long IgH CDR3 (CDR3H), which provided more contribution to the diverse expression of yak immunoglobulin. These findings might provide a theoretical basis for disease resistance breeding and vaccine development in yak.