Identification and diversity of Y-chromosome haplotypes in Qinghai yak populations.

The aim of the present study was to perform a preliminary analysis of the characterization and diversity of Y-chromosome haplotypes/haplogroups in yak of Qinghai Province, China. A total of 322 male yaks from nine populations belonging to three officially recognized breeds (Gaoyuan, Huanhu and Datong) were sampled. Animals were genotyped using six previously reported Y-SNPs present in the SRY, USP9Y, UTY, AMELY and OFD1Y genes and four new Y-SNPs in the OFD1Y gene (g.569A>C, g.578A>C, g.608G>T and g.653G>C) identified in this study. Seven Y-chromosome haplotypes (H1-H7) were identified according to the combination of the 10 Y-SNPs. H1, H2 and H6 were the most common and shared haplotypes across all yak populations/breeds. Private haplotypes H3 and H7 were detected in the Datong breed; H4 in Guoleimude, Qumalai, Qilian, Tianjun and Ganglong populations; and H5 in Qumalai of Gaoyuan breed. Haplotype clustering and network analyses inferred two haplogroups, Y1 and Y2, indicating two divergent lineages of paternal origins of Qinghai yak. The analysis of molecular variance showed a significant difference among individuals (P < 0.0001) with more than 93% of the total genetic variation present within populations, suggesting a weak genetic structure among Qinghai yak populations. The overall Y-haplotype diversity was 0.538 ± 0.028, showing a relatively high diversity in Qinghai yak. The Gaoyuan and Datong breeds had similar haplotype diversities (0.547 ± 0.030 and 0.553 ± 0.083, respectively), which were higher than that of the Huanhu breed (0.441 ± 0.098). Our results support the conservation and sustainable use of unique yak genetic resources in Qinghai.

High polymorphism at microsatellite loci in the Chinese donkey.

To reveal the genetic diversity and phylogenetic relationships between Chinese donkey breeds, 415 individuals representing ten breeds were investigated using ten microsatellite markers. The observed number of alleles, mean effective number of alleles (NE), mean expected heterozygosity (HE), and polymorphic information content (PIC) of each breed and polymorphic locus were analyzed. The results showed that seven (HTG7, HTG10, AHT4, HTG6, HMS6, HMS3, and HMS7) of ten microsatellite loci were polymorphic. The mean PIC, HE, and NE of seven polymorphic loci for the ten donkey breeds were 0.7679, 0.8072, and 6.0275, respectively. These results suggest that domestic Chinese donkey breeds possess higher levels of genetic diversity and heterozygosity than foreign donkeys. A neighbor-joining tree based on Nei's standard genetic distance showed that there was close genetic distance among Xinjiang, Qingyang, Xiji, and Guanzhong donkey breeds. In addition, Mongolia and Dezhou donkey breeds were placed in the same category. The phylogenetic tree revealed that the genetic relationships between Chinese donkey breeds are consistent with their geographic distribution and breeding history.

Analysis of POU1F1 gene DdeI polymorphism in Chinese goats.

As a member of the POU-domain family, the POU1F1 is a positive regulator for growth hormone, prolactin and thyroid-stimulating hormone b, by binding to target DNA promoters as a dimer in mammals. This study described the polymorphisms at the goat POU1F1-DdeI locus and analyzed the distribution of alleles in 15 indigenous Chinese goat breeds. The PCR-RFLP analysis showed a predominance of the D1D1 genotype and the D1 allele, with average frequencies of 0.550 and 0.790, respectively, irrespective of goat utility type. The D1D2 genotype was the second most frequent, with a mean frequency of 0.371. The distributions of genotypic and allelic frequencies at this locus were found to be significantly different among populations based on a Chi square test (P < 0.001), suggesting that the breed factor significantly affected the molecular genetic character of the POU1F1 gene. The genetic diversity analysis revealed that Chinese indigenous populations had a wide spectrum of genetic diversity at the goat POU1F1-DdeI locus. However, an ANOVA analysis revealed no significant differences in gene homozygosity, gene heterozygosity, effective allele numbers, or polymorphism information content among meat, dairy, and cashmere utility types (P > 0.05). This suggests that the goat utility types had no significant effect on the spectrum of genetic diversity.

Y-STR INRA189 polymorphisms in Chinese yak breeds.

To further explore Y-STR INRA189 polymorphisms in the yak, and to determine the genetic differences among yak breeds, genotyping analysis of INRA189 in 102 male yak individuals from three yak breeds in Qinghai Province of China was performed. Genotyping revealed the presence of four alleles, with sizes of 149, 155, 157, and 159 bp, respectively. Of these, the 157-bp allele, which was found with the highest frequency in the three yak breeds, was the dominant allele. Interestingly, the 149-bp allele was only detected in the Gaoyuan breed, and the 159-bp allele was only found in the Huanhu and Datong breeds. Only the 157- and 155-bp alleles were found in all three yak breeds. Taking the three yak breeds as a single population, the frequency of these four alleles was 0.0294, 0.0686, 0.8628, and 0.0392, respectively. The average polymorphism information content in the three yak breeds was 0.2379, indicating that the INRA189 was a low polymorphic Y-STR marker in yak.

Frequency of gray coat color in native Chinese horse breeds.

Gray horses are born colored, and they then gradually lose their hair pigmentation. Tremendous progress has been made in identifying the genes responsible for graying with age in horses in recent years. Results show that gray coat color in horses is caused by a 4.6-kb duplication in intron 6 of the syntaxin 17 gene (STX17), which constitutes a cis-acting-regulatory mutation. However, little is known about the gray phenotype in native Chinese horses. This study was conducted to explore the frequency distribution of the gray mutation in native Chinese horse breeds. A total of 489 samples from 14 native Chinese horse breeds were genotyped for the STX17 duplication using a simplified conventional PCR-based method. The results show that the gray mutation was present in 12 native Chinese horse breeds, except the Balikun and Guanzhong breeds. The Chakouyi and Hequ breeds had the highest frequency of the gray mutation (P(G) = 0.367 and P(G) = 0.274, respectively). There was no significant geographical difference in the distribution of gray coat color across native Chinese horse breeds. Our results suggest that gray is a common coat color in Chinese horses.

Novel Y-chromosome polymorphisms in Chinese domestic yak.

Y-chromosome-specific haplotypes (Y-haplotypes) constructed using single nucleotide polymorphisms (Y-SNPs) in the MSY (male-specific region of the Y-chromosome) are valuable in population genetic studies. But sequence variants in the yak MSY region have been poorly characterized so far. In this study, we screened a total of 16 Y-chromosome-specific gene segments from the ZFY, SRY, UTY, USP9Y, AMELY and OFD1Y genes to identify Y-SNPs in domestic yaks. Six novel Y-SNPs distributed in the USP9Y (g.223C>T), UTY19 (g.158A>C and g.169C>T), AMELY2 (g.261C>T), OFD1Y9 (g.165A>G) and SRY4 (g.104G>A) loci, which can define three Y-haplotypes (YH1, YH2 and YH3) in yaks, were discovered. YH1 was the dominant and presumably most ancient haplotype based on the comparison of UTY19 locus with other bovid species. Interestingly, we found informative UTY19 markers (g.158A>C and g.169C>T) that can effectively distinguish the three yak Y-haplotypes. The nucleotide diversity was 1.7 × 10(-4) ± 0.3 × 10(-4) , indicating rich Y-chromosome diversity in yaks. We identified two highly divergent lineages (YH1 and YH2 vs. YH3) that share similar frequencies (YH1 + YH2: 0.82-0.89, YH3: 0.11-0.18) among all three populations. In agreement with previous mtDNA studies, we supported the hypothesis that the two highly divergent lineages (YH1 and YH2 vs. YH3) derived from a single gene pool, which can be explained by the reunion of at least two paternal populations with the divergent lineages already accumulated before domestication. We estimated a divergence time of 408 110 years between the two divergent lineages, which is consistent with the data from mitochondrial DNA in yaks.

Polymorphism in the 5ꞌ-UTR of the insulin-like growth factor I gene associated with production traits in Chinese cattle.

The insulin-like growth factor I (IGF-1) gene plays important roles in the growth and body composition of animals. Serum IGF1 concentration has been associated with growth traits in many livestock species. We found a polymorphism of cattle IGF1-TasI locus and analyzed the distribution of alleles in three cattle breeds, including Qinchuan, Nanyang, and Chinese Holstein. PCR-RFLP analysis showed that allele A was the dominant allele. The frequencies of allele A varied from 0.84 to 0.97. Distributions of genotypic and allelic frequencies were significantly different among breeds. Polymorphism of the IGF1 gene was significantly affecting hucklebone width at 6 months in the Nanyang breed and protein and fat yield of the third lactation in Chinese Holstein cattle. Individuals with allele C had a significantly higher performance in production traits.

Analysis of the polymorphisms in the caprine Gli3 gene and their associations with production traits in goats.

Gli3 is a zinc finger transcription factor which plays a critical role in regulating animal development, metabolism and energy partitioning and thus has the potential to influence economical important traits in farm animals. In this study, we screened the complete exons of the caprine Gli3 gene using PCR-SSCP methods in 430 individuals from three goat breeds to identify sequence variants that might be associated with growth traits. Six novel mutations (GU363952:g.739C>G, 749A>T, 1636C>A, 1982delT, 1983T>C, 2856T>C) were identified. Significant associations were observed between the mutations GU363952:g.739C>G and g.749A>T with body height, chest circumference and canon circumference. Individuals with genotype G4-CC/AA and G4-CG/AT were significantly higher than individuals with genotype G4-GG/TT in body height, chest circumference and canon circumference. The results of this study suggested that the Gli3-gene-specific SNP could be a useful marker for growth traits in future marker-assisted selection programs in goat.

Paternal origins of Chinese cattle.

To determine the genetic diversity and paternal origin of Chinese cattle, 302 males from 16 Chinese native cattle breeds as well as 30 Holstein males and four Burma males as controls were analysed using four Y-SNPs and two Y-STRs. In Chinese bulls, the taurine Y1 and Y2 haplogroups and indicine Y3 haplogroup were detected in seven, 172 and 123 individuals respectively, and these frequencies varied among the Chinese cattle breeds examined. Y2 dominates in northern China (91.4%), and Y3 dominates in southern China (90.8%). Central China is an admixture zone, although Y2 predominates overall (72.0%). The geographical distributions of the Y2 and Y3 haplogroup frequencies revealed a pattern of male indicine introgression from south to north China. The three Y haplogroups were further classified into one Y1 haplotype, five Y2 haplotypes and one Y3 haplotype in Chinese native bulls. Due to the interplay between taurine and indicine types, Chinese cattle represent an extensive reservoir of genetic diversity. The Y haplotype distribution of Chinese cattle exhibited a clear geographical structure, which is consistent with mtDNA, historical and geographical information.

Copy number variation of PRAMEY across breeds and its association with male fertility in Holstein sires.

Multi-copy gene families are especially prevalent in the male-specific region (MSY) of the mammalian Y chromosome. Copy number variations (CNV) of these Y-linked gene families have been shown to affect human and animal fertility. The PRAMEY (Preferentially expressed antigen in melanoma, Y-linked) gene family is a newly identified, bovid-specific Y-linked gene family, which codes for a cancer/testis antigen that is expressed predominantly in testis and various tumors. The PRAMEY gene family is believed to play an important role in spermatogenesis and male fertility in cattle. The objective of this study was to investigate the CNV of PRAMEY within and across breeds and to determine whether CNV was associated with reproductive traits in Holstein bulls. A quantitative real-time PCR method was applied to measure the copy number of PRAMEY among 460 bulls using a Y-linked single copy gene, DDX3Y (DEAD box polypeptide 3, Y-linked), as a reference. The median copy number of PRAMEY was 13, ranging from 2 to 31. Significant variations in PRAMEY copy number were observed among 15 breeds investigated. Holstein bulls had the lowest median copy number (12), whereas Limousin bulls possessed the highest median copy number (26). Furthermore, bulls in the taurine lineage (13) had a significantly lower median copy number than those bulls in the indicine lineage (20). Association analysis revealed that PRAMEY copy number was correlated negatively with scrotal circumference (SC), relative scrotal circumference (RLSC), percentage of normal sperm (PNS), and nonreturn rate (NRR), but had no significant association with postthaw motility (PTM), incubated motility (IM), percentage of intact acrosome (PIA), sire conception rate (SCR), or relative breeding efficiency (RBE). The data from this study indicate that CNV of the PRAMEY gene family is associated with male reproductive traits and may serve as a valuable marker for sire fertility selection at an early age in cattle.

Impacts of single nucleotide polymorphisms and haplotypes in the bovine Dapper1 gene on body weight.

The Dapper1 protein plays important role in multiple developmental processes via negative modulation of the Wnt signaling pathway. We detected variations in Dapper1 in 1185 individuals from 5 Chinese cattle breeds and determined their effects on bovine body weight. Two silent mutations (g.8344C>T and g.8428C>T) in exon 6 along with two substitutions (g.10513A>G and g.10765C>G) in the 3'-untranslated region were detected with DNA pool sequencing and forced polymerase chain reaction-restriction fragment length polymorphism. Haplotype variability and the extent of linkage disequilibrium of the 4 single nucleotide polymorphisms (SNPs) were analyzed, and the results revealed 16 haplotypes and 7 combined haplotypes in the 5 cattle breeds. Statistical analyses indicated that genotypes CC and AA in the g.8344C>T and g.10513A>G loci were associated with heavier body weight at 6 months in the Nanyang cattle population (P < 0.05), and the combined haplotype had consistent significant effects on body weight with a single SNP. Cattle with haplotype combinations H1H5 (CCCTAACC) displayed the heaviest body weight at 6 months compared with that of other haplotypes (P < 0.05). Our results provide evidence that 4 SNPs and haplotypes in Dapper1 may be used for marker-assisted selection in beef cattle breeding programs.

[Developmental expression patterns and association study with growth traits of bovine].

As a member of the basic helix-loop-helix (bHLH) family of transcription factors, Bhlhe40 played an important role in the regulation of adipogenesis, myogenesis and the development of metabolic syndrome. In this study, we investigated the tissue expression patterns and differences of bovine Bhlhe40 gene during three developmental stages. The result showed that Bhlhe40 was ubiquitously expressed in most tissues of cattle. In addition, the expression of bovine Bhlhe40 gene showed a decreasing trend in skeletal muscle and fat during the de- velopmental stages. Then, two novel mutations (EX5 + 114 T>C, L166P and EX5 + 733 A>G, S372S) of bovine Bhlhe40 gene were identified by BamHI and ApaI ACRS PCR-RFLP in 1226 individuals from five indigenous cattle breeds in China. Frequencies of allele C at the BamHI locus varied from 0.210 to 0.340 among breeds, while frequencies of allele G at the ApaI locus varied from 0.030 to 0.114. Association analysis revealed no significant association of ApaI locus with growth traits in Nanyang breed. However, BamHI locus was significantly associated with the average daily lain at 18 months in Nanvans cattle (P < 0.05). This study aimed to lay the groundwork to further study of Bhlhe40 function at myogenesis and adipogenesis in bovine and should significantly contribute to cattle breeding and genetics through MAS program.

Polymorphisms in the Promoter Region of the Chinese Bovine PPARGC1A Gene.

The peroxisome proliferator-activated receptor gamma coactivator-1 alpha protein, encoded by the PPARGC1A gene, plays an important role in energy homeostasis. The genetic variations within the PPARGC1A gene promoter region were scanned in 808 Chinese native bovines belonging to three cattle breeds and yaks. A total of 6 SNPs and one 4 bp insertion variation in the promoter region of the bovine PPARGC1A gene were identified: SNP -259 T>A, -301_-298insCTTT, -915 A>G, -1175 T>G, -1590 C>T, -1665 C>T and -1690 G>A, which are in the binding sites of some important transcription factors: sex-determining region Y (SRY), myeloid-specific zinc finger-1 (MZF-1) and octamer factor 1(Oct-1). It is expected that these polymorphisms may regulate PPARGC1A gene transcription and might have consequences at a regulatory level.

Effects of CSN1S2 Genotypes on Economic Traits in Chinese Dairy Goats.

The aim of this study was to investigate allele frequencies at the CSN1S2 locus in two Chinese dairy goat breeds and the effects of its variation on dairy goat economic traits. Seven hundred and eight goats from Xinong Saanen (XS, n = 268) and Guanzhong (GZ, N = 440) breeds were selected. The milk samples of 268 XS goats were collected during the middle of lactation, body size parameters (708 goats) and daily milk yield (202 goats) were registered. The RFLP (restriction fragment length polymorphism) and SSCP (single strand conformation polymorphism) were used to detect the polymorphisms in CSN1S2. The Hardy-Weinberg (HW) equilibrium and the associations between body size, milk yield and composition and the genotypes were calculated. The results revealed that only A and F CSN1S2 alleles were found in the two Chinese dairy goat breeds. Allelic frequencies of A and F were 0.795, 0.205 and 0.739, 0.261 in Xinong Saanen and Guanzhong population respectively. Xinong Saanen breed was in Hardy-Weinberg equilibrium, while Guanzhong breed deviated from Hardy-Weinberg equilibrium (p<0.05). The association of polymorphism with economic traits indicated that the goats with FF genotype have higher milk fat and total solid concentration than those with AA and AF genotypes (p<0.05).

A novel 28-bp insertion-deletion polymorphism within goat PRNP gene and its association with production traits in Chinese native breeds.

In this study, a novel 28-bp insertion-deletion (indel) polymorphism (AJ298878:g.47836-47853insCCTCAGACACTGAGTCTCCCCAACAGCA) was found in goat prion protein (PRNP) gene in 2373 goats from 13 Chinese native breeds. The frequencies of allele "ins" varied from 0.500 to 1.000 in different breeds. The establishment of association of the 28-bp indel polymorphism with production traits was performed in Inner Mongolia white cashmere (IMWC) and Xinong Sannen dairy (XNSN) breeds. Two significant associations between this polymorphism and 1-year-old body mass (P = 0.011) and average body mass (P = 0.024) were observed in IMWC breed, as well as wool thickness of 3-year-olds (P < 0.001). Furthermore, the novel 28-bp indel polymorphism was significantly associated with total solids in the evening (%) (P = 0.009) and milk yield (P = 0.016) in XNSN breed. These findings suggested that the 28-bp indel polymorphism was a potential DNA marker for eliminating or selecting preferred individuals in relation to production traits in goat marker-assisted selection breeding while carrying out preventing scrapie project.

Characterization of cytochrome b diversity in Chinese domestic horses.

Previous mitochondrial DNA (mtDNA) D-loop and microsatellite studies have shown that Chinese horses have multiple maternal origins and high genetic diversity. To better characterize maternal genetic origins and diversity of Chinese domestic horses, we conducted a comprehensive analysis of 407 complete 1140 bp sequences of the horse mitochondrially encoded cytochrome b (CYTB) gene, including 323 horses from 13 Chinese indigenous breeds and 84 reference sequences from GenBank. A total of 114 haplotypes were identified, of which 73 appeared among the 13 Chinese horse breeds. The high mitochondrially encoded cytochrome b haplotypic diversity suggests multiple maternal origins in Chinese horses.

Single nucleotide polymorphisms of the bovine VEGF-B gene and their associations with growth traits in the Nanyang cattle breed.

PCR-SSCP and DNA sequencing methods were applied to reveal single nucleotide polymorphisms (SNPs) in the bovine VEGF-B gene in 675 samples belonging to three native Chinese cattle breeds. We found 3 SNPs and a duplication NC_007330.5: g. [782 A>G p. (Gly112 =) (;) 1000-1001dup CT (;) 1079 C>T (;) 2129 G>A p. (Arg184Gln)]. We also observed a statistically significant association of the polymorphism (1000-1001dup CT) in intron 3 of the VEGF-B gene with the body weight of the Nanyang cattle (p < 0.05). This polymorphisms of VEGF-B gene need to be verified among a larger cattle population before it can be identified as a marker for bovine body weight.

Polymorphism of DLK1 and CLPG gene and their association with phenotypic traits in Chinese cattle.

DLK1 and CLPG were located in DLK1-GTL2 imprinted cluster. They all affected muscle growth and meat tenderness. The functional importance of DLK1 and CLPG imply that the variation of the genes could affect the growth traits of animal. PCR-SSCP and sequencing were used to analyze the four loci of DLK1 gene and CLPG gene in 1109 individuals, which belong to eight breeds/species of bovidae, including cattle, buffalo and yak. A synonymous mutation (C451T) was detected in exon 5 of DLK1 in Qinchuan cattle, but didn't change significantly with phenotypic traits. Three genotypes AA, AB and AC of CLPG were identified in Jiaxian cattle. The associations analyst of different genotypes showed that the individuals with genotypes AA and AC had a greater body weight and longer body length than those with genotype AB (P<0.05 and P<0.01, respectively); the AA individuals were different from those AB (P<0.05) in the circumference of cannon bone. No polymorphism was observed in the other populations at other loci. These results were in agreement with the homology analysis: DLK1 and CLPG genes were in a highly conserved.

The CSN1S1 N and F alleles identified by PCR-SSCP and their associations with milk yield and composition in Chinese dairy goats.

A method was depicted to identify null allele CSN1S1 N and low allele CSN1S1 F of the CSN1S1 gene of goat using PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism). First, primer A was designed to amplify the exon 9 of CSN1S1 gene which produced three genotypes AA, AB, and BB. Among these three genotypes, only AA and AB individuals had a cytosine deletion at exon 9 after DNA sequencing, which cannot be used to identify the N and F alleles. Therefore, primer B was used to amplify intron 14 of CSN1S1 of described AA and AB individuals. Genotypes FF, FN and NN were detected within AA individuals and genotypes FO and NO were detected in the above AB individuals. The frequencies of F and N alleles in 708 samples from Xinong Saanen (XS) and Guanzhong (GZ) dairy goat breeds were 0.1139, 0.0927, and 0.2376, 0.1193, respectively. In 268 XS samples, the individuals with NN genotype contained a significant lower protein content than that of other genotypes (P<0.01). Individuals of FF genotype had significant higher milk yield than that of NO genotype in the first milk lactation of 202 XS individuals (P<0.05). Therefore, the variability at CSN1S1 locus contains enough genetic diversity to be potentially useful in improving the quality and production of milk in Chinese dairy goat breeds.

Sequence variants in the bovine nucleophosmin 1 gene, their linkage and their associations with body weight in native cattle breeds in China.

The nucleophosmin (nucleolar phosphoprotein B23, numatrin) gene (NPM1, previously known as nucleophosmin/nucleoplasmin family, member 1) encodes a multifunctional nucleolar phosphoprotein that plays a crucial role in cell growth and homeostasis. Seven sequence variants (SVs) were identified in the coding region of bovine NPM1, five of which were in complete linkage disequilibrium. Eight different haplotypes were identified, of which two major haplotypes have a frequency of 23.2% and 20.4%. Three SVs were significantly associated with body weight in the Nanyang population as analysed at different ages. No significant association was detected between 18 combined genotypes and body weight at five different ages. Our results suggest that some polymorphisms in NPM1 are associated with body weight at some ages and may be used as candidates for marker-assisted selection and management in beef cattle breeding programmes.