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The loss of local chicken breeds as result of replacement with cosmopolitan breeds indicates the need for conservation measures to protect the future of local genetic stocks. The aim of this study is to describe the patterns of polymorphism of the hypervariable control region of mitochondrial DNA (HVR1) in domestic chicken in China's Jiangxi province to investigate genetic diversity, genetic structure and phylo-dynamics. To this end, we sequenced the mtDNA HVR1 in 231 chickens including 22 individuals which belonged to previously published sequences. A neighbor-joining tree revealed that these samples clustered into five lineages (Lineages A, B, C, E and G). The highest haplotype diversity and nucleotide diversity were both found in Anyi tile-liked gray breed. We estimated that the most recent common ancestor of the local chicken existed approximately 16 million years ago. The mismatch distribution analysis showed two major peaks at positions 4 and 9, while the neutrality test (Tajima's D = −2.19, p < 0.05) and Fu's F-statistics (−8.59, p < 0.05) revealed a significant departure from the neutrality assumption. These results support the idea that domestication of chickens facilitated population increases. Results of a global AMOVA indicated that there was no obvious geographic structure among the local chicken breeds analyzed in this study. The data obtained in this study will assist future conservation management of local breeds and also reveals intriguing implications for the history of human population movements and commerce. [ABSTRACT FROM AUTHOR]

Summary The purpose of this study was to assess the genetic characteristics of six breeds of Chinese local sheep using 19 microsatellite loci and to effectively validate statistical methods for individual assignment based on informative microsatellites. All the six breeds deviated from Hardy-Weinberg equilibrium expectations, while the majority of markers complied. The polymorphism information content (PIC) of overall loci for the six populations ranged from 0.283 ( SRCRSP5) to 0.852 ( OarVH72). Tibetan sheep were the most diverse population with the highest mean allelic richness (6.895), while Ujmuqin (UQ) harboured the lowest allelic richness (6.000). The F-statistics for the six populations were FIS = −0.172, FIT = −0.082 and FST = 0.077, respectively. Furthermore, the pair-wise FIS revealed a moderate genetic differentiation among populations ( P < 0.01), indicating that all breeds can be considered genetically independent entities. The lowest genetic differentiation was between Tengchong (TC) and UQ ( FST = 0.041), and the highest one was between TC and Fat-tailed Han ( FST = 0.111). In comparing the three statistical models, we note that the seven microsatellite loci ( MAF65, OarJMP58, SRCRSP9, MCM140, OarAE129, BM8125 and SRCRSP5) commonly used for individual assignment will ensure a powerful detection of individual origin, with accuracy up to 91.87%, when the likelihood-based method is used. Overall, these findings shed light onto the genetic characteristics of Chinese indigenous sheep and offer a set of microsatellite loci that is simple, economic and highly informative for individual assignment of Chinese sheep. [ABSTRACT FROM AUTHOR]

The genetic diversity and phylogenetic survey of native sheep breeds in the eastern and southern Central Asia were assessed in the present study. The clustering, principal components, structure and F statistics all demonstrate that the native sheep breeds in these regions be classified into two genetic groups: Mongolia-Tibetan sheep group and South-Southeast Asia sheep group. The Mongolia sheep group and the Tibetan sheep group had a certain degree of gene communication from the ancient times. In the present study we demonstrated that the Chinese native sheep populations belonged to Mongolia-Tibetan sheep group. However, the relationships among the sheep populations in Mongolia sheep group in China were not closely related to the geographical distance among sheep populations. [ABSTRACT FROM AUTHOR]

A single nucleotide polymorphism of 5′ flanking region of the prolactin gene was investigated in both high prolificacy breeds (Small Tail Han and Hu sheep) and low prolificacy breeds (Dorset and Suffolk sheep) using polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP). The results indicated that two genotypes (AA and AB) were detected in Small Tail Han sheep (n = 239), only one genotype (AA) was detected in Hu (n = 40), Dorset (n = 50) and Suffolk sheep (n = 39). The mutant homozygous genotype (BB) was not detected in four sheep breeds. In Small Tail Han sheep (n = 239), the frequency of genotypes AA and AB was 0.91 and 0.09, the frequency of the A and B alleles was 0.95 and 0.05, respectively. The fitness tests showed that the Small Tail Han sheep population was in Hardy–Weinberg equilibrium. Sequencing revealed a mutation (G→T) at the position 63 bp of the 5′ flanking region of prolactin gene in AB genotype compared with AA genotype in Small Tail Han sheep. The Small Tail Han ewes with AB genotype had 0.83 (p < 0.05) lambs more than those with AA genotype. These results preliminarily showed that the prolactin locus is either a major gene that influences the high prolificacy in Small Tail Han sheep or is in close linkage with such a gene. [ABSTRACT FROM AUTHOR]

It is generally believed that domestic sheep have two maternal lineages (haplotypes A and B), based on mitochondrial DNA analysis. In the present study, we provide evidence that a novel maternal lineage (haplotype C) is exhibited in Chinese native sheep. To verify this finding, 231 samples were collected from six Chinese local breeds, which cover the vast geographical region of sheep inhabitation in China. For comparison, 50 samples were collected from two Western breeds collected in China. Mitochondrial DNA was screened by PCR single-strand conformational polymorphism (SSCP), leading to the identification of novel band patterns in ND2 and ND4 genes in the Chinese breeds. Interestingly, mutations at the two loci were in strong linkage disequilibrium. Direct sequencing of the DNA fragments revealed a non-synonymous substitution in ND2. Furthermore, two synonymous mutations were identified by comparisons of the novel type (haplotype C) and the established types (haplotypes A and B). The entire mitochondrial control region for 55 samples was then sequenced to construct a phylogenetic tree and median joining network. Both the tree and network demonstrated a topology of three groups, which is in consistent with the SSCP analysis. Unlike Western breeds, Chinese breeds are composed mainly of haplotypes A and B, but with a small fraction of haplotype C. According to Fu's test and mismatch distribution, haplotype C has not been subject to a recent population expansion. Based on these results, we propose a novel origin for Chinese sheep. [ABSTRACT FROM AUTHOR]