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Background: High spontaneous miscarriage rate in yak, especially during late pregnancy, have caused a great economic loss to herdsmen living in the Qinghai-Tibet plateau. However, the mechanism underlying spontaneous miscarriage is still poorly understood. In the present study, placenta protein markers were identified to elucidate the pathological reasons for yak spontaneous miscarriage through isobaric tags for relative and absolute quantification (iTRAQ) proteomic technology and bioinformatic approaches. Results: Subsequently, a total of 415 differentially expressed proteins (DEPs) were identified between aborted and normal placentas. The up-regulated DEPs in the aborted placentas were significantly associated with "spinocerebellar ataxia", "sphingolipid signalling", "relaxin signalling", "protein export", "protein digestion and absorption" and "aldosterone synthesis and secretion" pathway. While the down-regulated DEPs in the aborted placentas mainly participated in "valine, leucine and isoleucine degradation", "PPAR signalling", "peroxisome", "oxidative phosphorylation", "galactose metabolism", "fatty acid degradation", "cysteine and methionine metabolism" and "citrate cycle" pathway. Conclusions: The results implied that the identified DEPs could be considered as placental protein markers for yak miscarriage during late pregnancy, and biomacromolecule metabolic abnormality and oxidative damage might be responsible for the high spontaneous miscarriage rate in yak. These findings provide an important theoretical basis for deciphering the pathologic mechanism of late spontaneous miscarriage in yak. [ABSTRACT FROM AUTHOR]

Background and aim: Mitochondrial 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. Results: Complete 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. Conclusions: Thegenetic diversity of yaks in Qinghai was high. Both domestic and wild yaks clusteredinto three branches. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In the present study, we reported the complete mitochondrial DNA sequence of the hybrid from wild yak (♂) × domestic yak (♀). The mitochondrial genome is 16,322 bp in length, including the typical structure of 22 transfer RNA genes, 13 protein-coding genes, 2 ribosomal RNA genes, and 1 non-coding control region. The overall nucleotide composition is: 33.74% A, 13.18% G, 25.86% C, and 27.21% T. The phylogenetic analysis by neighbor-joining (NJ) method showed that the hybrid of wild yak (♂) × domestic yak (♀) has a closer relationship to the Qinghai Plateau yak. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]