The research progress of genomic selection in livestock.

With the development of gene chip and breeding technology, genomic selection in plants and animals has become research hotspots in recent years. Genomic selection has been extensively applied to all kinds of economic livestock, due to its high accuracy, short generation intervals and low breeding costs. In this review, we summarize genotyping technology and the methods for genomic breeding value estimation, the latter including the least square method, RR-BLUP, GBLUP, ssGBLUP, BayesA and BayesB. We also cover basic principles of genomic selection and compare their genetic marker ranges, genomic selection accuracy and operational speed. In addition, we list common indicators, methods and influencing factors that are related to genomic selection accuracy. Lastly, we discuss latest applications and the current problems of genomic selection at home and abroad. Importantly, we envision future status of genomic selection research, including multi-trait and multi-population genomic selection, as well as impact of whole genome sequencing and dominant effects on genomic selection. This review will provide some venues for other breeders to further understand genome selection.

Expression sequence tag and QTL/MAS of goat/sheep in China.

Goats/sheep are important in the animal agriculture of China. Distribution of these animals in China is closely related to the economic performance and ecological conditions in the specific regions. Comparative genome study is popular in China although the sheep and goat genome information are not well sequenced. Expression Sequence Tags (EST) are well developed in skin and ovary organ. Transgenic productions are focused on goat milk chiefly. Microsatellite DNA and mtDNA polymorphism were used to analyze the genetic structure mainly and some of them were used to detect the Quantitative Trait Loci(QTL) of goat and sheep. Only the candidate gene markers are used as Marker Assisted Selection (MAS) and integrated into Best Linear Unbiased Prediction (BLUP) selection strategy in goat and sheep nucleus breeding flock according to different breeds. Although some studies have proposed direct selection on the individual gene loci responsible for the genetic variation in some traits, there are 20 goat/sheep gene patents in the past decade. Some patents on gene with extremely broad claims will shadow over the commercialization of these gene and fill the blank of the gene patents in goat/sheep fields.

A subset of skin-expressed microRNAs with possible roles in goat and sheep hair growth based on expression profiling of mammalian microRNAs.

The microRNAs (miRNAs) are an extensive class of small noncoding RNAs (18-25 nucleotides) with probable roles in the regulation of gene expression. Due to the fact that miRNAs are conserved in closely related eukaryotes and some are also conserved across a larger evolutionary distance, their potential functions in mammalian development are under active study. In order to identify mammalian miRNAs that might function in hair growth, we characterized the expression of 159 miRNAs in adult body side skin and ear skin from goat and sheep using microarray analysis. Of these, 19 miRNAs were specifically expressed or greatly enriched in body side skin in goats and sheep. This suggests hair growth-specific functions for miRNAs. Of the coexpressed 105 miRNAs, the degree of correlation within species is higher than interspecies. Nine of the expressed miRNAs were detected exclusively in the goat body side skin area where more cashmere was grown than coat hair; mmu-miR-720 and mmu-miR-199b were expressed primarily in goat skin. The identification of 105 of skin-expressed miRNAs whose expression behavior is conserved in goats and sheep differentiating hair follicles implicates these miRNAs have functions in mammalian hair follicles growth and development. We demonstrate that miRNAs previously associated with hair follicles in the mouse are also expressed in the adult skin of goats and sheep. In addition, 69 more conserved miRNAs cross-species were discerned in the study. Of them, the let-7, mir-17, mir-30, mir-15, and mir-8 gene families were expressed in high frequency. These results reveal critical roles of them in skin and hair follicle development and function.