Identification of Candidate Genes for Pigmentation in Camels Using Genotyping-by-Sequencing

Simple Summary The coat color of dromedary is usually uniform and varies from black to white. We identified 9 significant SNPs associated with white color, and the 13 significant SNPs associated with black color using genotyping-by-sequencing (GBS). Among candidate genes, SNAI1 that interacts with MCIR, ASIP and KIT genes plays a key role in the melanin biosynthetic and pigmentation biological process and melanogenesis biological pathway. The coat color of dromedary is usually uniform and varies from black to white, although dark- to light-brown colors are the most common phenotypes. This project was designed to gain knowledge on novel color-related variants using genotyping-by-sequencing (GBS). The association between the SNPs and coat color was tested using MLM (mixed linear models) with kinship matrix. Three GWAS models including white color vs. non-white color, black vs. non-black color, and light-brown vs. dark-brown color were performed. There were no distinct genetic clusters detected based on the color phenotypes. However, admixture occurred among all individuals of the four different coat color groups. We identified nine significant SNPs associated with white color after Bonferroni correction, located close to ANKRD26, GNB1, TSPYL4, TEKT5, DEXI, CIITA, TVP23B, CLEC16A, TMPRSS13, FXYD6, MPZL3, ANKRD26, HFM1, CDC7, TGFBR3, and HACE1 genes in neighboring flanking regions. The 13 significant SNPs associated with black color and the candidate genes were: CAPN7, CHRM4, CIITA, CLEC16A, COL4A4, COL6A6, CREB3L1, DEXI, DGKZ, DGKZ, EAF1, HDLBP, INPP5F, MCMBP, MDK, SEC23IP, SNAI1, TBX15, TEKT5, TMEM189, trpS, TSPYL4, TVP23B, and UBE2V1. The SNAI1 gene interacted with MCIR, ASIP and KIT genes. These genes play a key role in the melanin biosynthetic and pigmentation biological process and melanogenesis biological pathway. Further research using a larger sample size and pedigree data will allow confirmation of associated SNPs and the identified candidate genes.

Automated summary

This study identified SNPs associated with coat color in dromedaries using GBS and highlighted the role of the SNAI1 gene in melanin biosynthesis and pigmentation. Despite the absence of distinct genetic clusters based on coat color phenotypes, admixture was observed in the four different coat color groups.