PPARγ, FAS, HSL mRNA and protein expression during Tan sheep fat-tail development

Genetics of the phenotypic evolution in sheep: a molecular look at diversity-driving genes

BACKGROUND

After domestication, the evolution of phenotypically-varied sheep breeds has generated rich biodiversity. This wide phenotypic variation arises as a result of hidden genomic changes that range from a single nucleotide to several thousands of nucleotides. Thus, it is of interest and significance to reveal and understand the genomic changes underlying the phenotypic variation of sheep breeds in order to drive selection towards economically important traits.

REVIEW

Various traits contribute to the emergence of variation in sheep phenotypic characteristics, including coat color, horns, tail, wool, ears, udder, vertebrae, among others. The genes that determine most of these phenotypic traits have been investigated, which has generated knowledge regarding the genetic determinism of several agriculturally-relevant traits in sheep. In this review, we discuss the genomic knowledge that has emerged in the past few decades regarding the phenotypic traits in sheep, and our ultimate aim is to encourage its practical application in sheep breeding. In addition, in order to expand the current understanding of the sheep genome, we shed light on research gaps that require further investigation.

CONCLUSIONS

Although significant research efforts have been conducted in the past few decades, several aspects of the sheep genome remain unexplored. For the full utilization of the current knowledge of the sheep genome, a wide practical application is still required in order to boost sheep productive performance and contribute to the generation of improved sheep breeds. The accumulated knowledge on the sheep genome will help advance and strengthen sheep breeding programs to face future challenges in the sector, such as climate change, global human population growth, and the increasing demand for products of animal origin.

Genetic polymorphism association analysis of SNPs on the species conservation genes of Tan sheep and Hu sheep

For further understanding the genetic control mechanisms of growth and development in Tan sheep, and culturing good traits on meat performance, which is very important to both in developing local species and improving economic efficaciously. In our study, we recruited a total of 250 Tan sheep and 174 healthy Hu sheep to detect 32 SNPs in GH, GHR, NPY, Leptin, H-FABP, MSTN, and CAST by using direct sequencing techniques, in order to explore genetic marking loci which were an association with growth characters. From the results, we found different SNPs with an obvious difference for the growth traits. In the different genetic model analysis, we found SNP12, SNP29, SNP41, SNP8, SNP34, SNP35, SNP9, SNP10, SNP36, SNP45, and SNP39 were a significantly negative association with the two kinds of sheep. And SNP46, SNP42, and SNP69 with the positive association between the different trait in sheep were analyzed. From the LD and haplotype analysis, we found three blocks with the positive association in growth traits between Tan sheep and Hu sheep. The block of SNP29, SNP32, SNP34, SNP35, SNP36, SNP39, SNP41, SNP42, SNP45, and SNP46 with the genotype “AATCTACTTA” is the most significantly association with the traits. In summary, the study initially explored the genes for growth and reproduction between Tan sheep and Hu sheep and found some statistically significant results which demonstrate that there are genetic differences. These differential molecular markers may provide a scientific theoretical basis for the preferred species of Tan sheep which with good meat performance and better utilization of species resources.