Comparative transcriptome and histological analyses provide insights into the skin pigmentation in Minxian black fur sheep (Ovis aries)

Xiaolei Shi; Jianping Wu; Xia Lang; Cailian Wang; Yan Bai; David Greg Riley; Lishan Liu; Xiaoming Ma

doi:10.7717/peerj.11122

Comparative transcriptome and histological analyses provide insights into the skin pigmentation in Minxian black fur sheep (Ovis aries)

PeerJ. 2021 Apr 27:9:e11122. doi: 10.7717/peerj.11122. eCollection 2021.

Authors

Xiaolei Shi¹, Jianping Wu¹, Xia Lang², Cailian Wang^{2

3}, Yan Bai¹, David Greg Riley⁴, Lishan Liu², Xiaoming Ma¹

Affiliations

¹ College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu Province, China.
² Animal Husbandry, Pasture, and Green Agriculture Institute, Gansu Academy of Agricultural Sciences, Lanzhou, Gansu Province, China.
³ Key Laboratory for Sheep, Goat, and Cattle Germplasm and Straw Feed in Gansu Province, Lanzhou, Gansu Province, China.
⁴ Department of Animal Science, Texas A&M University, College Station, TX, USA.

Abstract

Background: Minxian black fur (MBF) sheep are found in the northwestern parts of China. These sheep have developed several special traits. Skin color is a phenotype subject to strong natural selection and diverse skin colors are likely a consequence of differences in gene regulation.

Methods: Skin structure, color differences, and gene expression (determined by RNA sequencing) were evaluated the Minxian black fur and Small-tail Han sheep (n = 3 each group), which are both native Chinese sheep breeds.

Results: Small-tail Han sheep have a thicker skin and dermis than the Minxian black fur sheep (P < 0.01); however, the quantity of melanin granules is greater (P < 0.01) in Minxian black fur sheep with a more extensive distribution in skin tissue and hair follicles. One hundred thirty-three differentially expressed genes were significantly associated with 37 ontological terms and two critical KEGG pathways for pigmentation ("tyrosine metabolism" and "melanogenesis" pathways). Important genes from those pathways with known involvement in pigmentation included OCA2 melanosomal transmembrane protein (OCA2), dopachrome tautomerase (DCT), tyrosinase (TYR) and tyrosinase related protein (TYRP1), melanocortin 1 receptor (MC1R), and premelanosome protein (PMEL). The results from our histological and transcriptome analyses will form a foundation for additional investigation into the genetic basis and regulation of pigmentation in these sheep breeds.

Keywords: Histology; Pigmentation; RNA sequencing; Sheep; Skin.

Grants and funding

This work was supported by China’s Agricultural Research system (CARS-39-18), the Innovation team of the Gansu Academy of Agricultural Sciences, and the Key Research and Development Plan of Gansu Province (No. 18YF1NA091). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.