T. Feng

Polymorphisms of coding region of BMPR-IB gene and their relationship with litter size in sheep

The bone morphogenetic protein receptor IB (BMPR-IB) was studied as a candidate gene for the prolificacy of sheep. Nine pairs of primers (P1–P9) were designed to detect single nucleotide polymorphisms (SNPs) of exons 1–4 and 6–10 of the BMPR-IB gene in both high (Small Tail Han and Hu sheep) and low prolificacy breeds (Texel and Chinese Merino sheep) by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP). Only the products amplified by primers P2, P5, P6, P7, P8 and P9 displayed polymorphisms. The present study identified 22 SNPs in partial coding regions of ovine BMPR-IB, in which 20 SNPs were reported for the first time. In total of the 22 mutations, 18 DNA variations were originated from the Hu breed, three were found in the Small Tail Han breed (two of them were found in other sheep breeds), three in the Chinese Merino breed, and none in the Texel breed. These results preliminarily demonstrated that BMPR-IB is a major gene affecting the hyperprolificacy in Small Tail Han and Hu sheep, and could be used as a molecular genetic marker for early auxiliary selection for hyperprolificacy in sheep.

Identification and verification of differentially expressed genes in the caprine hypothalamic‐pituitary‐gonadal axis that are associated with litter size

Litter size is a favorable economic trait for the goat industry, but remains a complex trait controlled by multiple genes in multiple organs. Several genes have been identified that may affect embryo survival, follicular development, and the health of fetuses during pregnancy. Jining Grey goats demonstrate the largest litter size among goat breeds indigenous to China. In order to better understand the genetic basis of this trait, six suppression subtractive hybridization (SSH) cDNA libraries were constructed using pooled mRNAs from hypothalamuses, pituitaries, and ovaries of sexually mature and adult polytocous Jining Grey goats, as testers, versus the pooled corresponding mRNAs of monotocous Liaoning Cashmere goats, as drivers. A total of 1,458 true‐positive clones —including 955 known genes and 481 known and 22 unknown expressed sequence tags—were obtained from the SSH libraries by sequencing and alignment. The known genes were categorized into cellular processes and signaling information storage and processing, and metabolism. Three genes (FTH1, GH, and SAA) were selected to validate the SSH results by quantitative real‐time PCR; all three were up‐regulated in the corresponding tissues in the tester group indicating that these are candidate genes associated with the large litter size of Jining Grey goats. Several other identified genes may affect embryo survival, follicular development, and health during pregnancy. This study provides insights into the mechanistic basis by which the caprine hypothalamic‐pituitary‐gonadal axis affects reproductive traits and provides a theoretical basis for goat production and breeding. Mol. Reprod. Dev. 82: 132–138, 2015.

Polymorphism of Prophet of Pit-1 gene and its relationship with litter size of Small Tail Han sheep.

1Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation of Ministry of Agriculture, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, People’s Republic of China 2College of Life Sciences, Anhui Agricultural University, Hefei 230036, People’s Republic of China 3College of Life Science, Liaoning Normal University, Dalian 116029, People’s Republic of China 4College of Animal Science and Technology, Agricultural University of Hebei, Baoding 071000, People’s Republic of China 5State Key Laboratory of Agricultural Biotechnology (China Agricultural University), Beijing 100193, People’s Republic of China