Research Progress on Phenotype Formation of Diluted Coat Color in Agricultural Economic Animals

Abstract

Coat color is considered to be one of the earliest selected traits during domestication of domestic animals, and the favorable selection for this trait results in the rich diversity of coat color of domestic animals. The coat color phenotype of domestic animals is determined by the relative amounts of eumelanins (black/brown) and pheomelanins (yellow/red) in melanocytes. When the synthesis of eumelanin or pheomelanins is diluted or when the synthesis of both pigments is diluted, a variety of diluted coat color phenotypes will be formed. In order to further understand the genetic mechanism of coat color variation in domestic animals, many scholars have conducted a large number of studies on the genetics of coat color to uncover genes and causal mutations associated with coat color. Currently, more than 300 gene loci and 150 genes related to coat color have been identified. Diluted coat color phenotype is an important research direction in the field of genetic research of animal coat color, and some progress has been made in its genetic research. Multiple causal genes have been reported to cause coat color dilution in mammals and feather color dilution in birds, and these genes generally affect melanocytes development and differentiation, melanin synthesis, and melanosome transport by influencing underlying pigment-forming pathways. Similar coat color dilution phenotype can often be found among species, which may be caused by conserved genes or by different genes. In the same species, there may be multiple genes that cause the same or similar diluted coat color phenotype. In the study, we reviewed the research progress on types of diluted coat color (feather color) phenotype of agricultural economic animals (mainly pigs, horses, cattle, sheep and chickens), the causal genes, mutations and genetic mechanisms of their formation, to provide references for further researches on the genetic mechanism of diluted coat color (feather color) in animals.

Keywords

• agricultural animal
• coat color variation
• coat color dilution
• coat color dilution gene
• genetic mechanism