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DIO2 was studied as a candidate gene for reproduction in sheep. Three pairs of primers were designed to detect single nucleotide polymorphisms (SNPs) of exon 2 of DIO2 in nonseasonal and seasonal reproduction breeds. The polymorphisms were detected using SeqMan II and analyzed by PCR-RFLP. The sheep DIO2 gene was cloned and its mutations were detected in five sheep breeds whose reproductive seasonality and litter sizes were different. Association analyses were performed to reveal the relationships between SNPs and reproductive seasonality as well as litter size in sheep. The results showed that a 1041-bp DNA fragment of the sheep DIO2 gene was obtained and a part of the coding sequence of 591 bp encodes 196 amino acids, having high homology with that of other mammals. Moreover, three mutations (G318T, G482C, and C885T) were detected. The test of genotype distribution in five sheep breeds showed that there were significant differences between nonseasonal and seasonal breeds for 318 and 482 loci. However, the associations between the three polymorphisms and sheep seasonal reproduction were not very distinct. Additionally, there was no significant associations between polymorphisms and litter sizes in Small Tail Han sheep. These results may provide the basic theory for further study. [ABSTRACT FROM AUTHOR]

The aims of study were to reveal the changes in genetic diversity in reproduction selection of sheep. Genetic polymorphisms of microsatellite GC101 locus and its linkage with the FecB gene were detected in Chinese local sheep (Small Tail Han and Hu sheep) and western sheep (Texel and Dorset) breeds. There was the same FecB mutation (A746G) in both Small Tail Han and Hu sheep as that in Booroola Merino ewes, but not in Texel and Dorset sheep. Seven alleles, from 192 bp to 210 bp, and 20 genotypes were detected at the GC101 locus in 447 individuals totally. The preponderant allele was 200 bp for Chinese sheep and 202 bp for western sheep. Linkage analysis showed that there was strong linkage disequilibrium between the 200-bp allele of the GC101 locus and the B allele of the FecB gene (r² = 0.639). These results preliminarily implied that both the 200-bp allele of the GC101 locus and the B allele of FecB had been reinforced in reproduction selection of Chinese sheep. The differentiation of GC101 allele distribution between Chinese sheep and western sheep also indicated that the FecB of Chinese sheep might be derived from Chinese local areas. [ABSTRACT FROM AUTHOR]

In our early work, one mutation (A898G, which caused Ser32Gly (S32G) change of mature peptide) was identified in the goat BMP15 gene and the allele G was associated with high litter size in Jining Grey goats (the goat breed with the highest fecundity in China). The aim of this research was to investigate the genetic structure of the prolific BMP15 gene in 18 goat breeds reared in China, including 12 native breeds, 3 introduced breeds, and 2 cultivated breeds. Genomic DNA of 1011 goats was screened for the S32G mutation. The results showed that this mutation existed in all 3 cultivated and 8 native goat breeds but in none of the 3 introduced goat breeds, which hinted that this mutation may originate from native goat breeds of China. Besides the Jining Grey goats, the BMP15 gene was also a potential prolificacy gene in Matou goats. Moreover, the structure prediction indicated that the S32G mutation might participate in the binding of BMP15 with receptors. [ABSTRACT FROM AUTHOR]

Single nucleotide polymorphisms of the 5' regulatory region of the FSHR gene were detected in 3 goat breeds (Jining Grey, Boer, and Inner Mongolia Cashmere) by the polymerase chain reaction-single-strand conformation polymorphism method, and its effects on litter size in Jining Grey goats were also evaluated. Concerning primer P1, 2 genotypes (AA and BB) were detected in Boer goats, while only the AA genotype was identified in Jining Grey and Inner Mongolia Cashmere goats. Sequencing revealed a T→A transversion at the 26th position and an A→C transversion at the 61st position of the amplified region in genotype BB in comparison to genotype AA. Regarding primer P2, 3 genotypes (CC, CD, and DD) were identified in the 3 goat breeds mentioned above. Sequencing revealed a T→A transversion at the 70th position and a G→C transversion at the 130th position of the amplified region in genotype DD compared with CC. Does with genotype CC had 0.46 (P < 0.05) or 1.03 (P < 0.05) kids more than those with genotype CD or DD, respectively, while does with CD had 0.57 (P < 0.05) kids more than those with DD in Jining Grey goats. These results preliminarily showed that allele C of the FSHR gene was a potential marker for improving litter size in goats. [ABSTRACT FROM AUTHOR]