A Stop-Gain Mutation within MLPH Is Responsible for the Lilac Dilution Observed in Jacob Sheep.

Christian J Posbergh,Elizabeth A Staiger,Heather J Huson

doi:10.3390/genes11060618

Abstract

A coat color dilution, called lilac, was observed within the Jacob sheep breed. This dilution results in sheep appearing gray, where black would normally occur. Pedigree analysis suggested an autosomal recessive inheritance. Whole-genome sequencing of a dilute case, a known carrier, and sixteen non-dilute sheep was used to identify the molecular variant responsible for the coat color change. Through investigation of the genes MLPH, MYO5A, and RAB27A, we discovered a nonsynonymous mutation within MLPH, which appeared to match the reported autosomal recessive nature of the lilac dilution. This mutation (NC_019458.2:g.3451931C>A) results in a premature stop codon being introduced early in the protein (NP_001139743.1:p.Glu14*), likely losing its function. Validation testing of additional lilac Jacob sheep and known carriers, unrelated to the original case, showed a complete concordance between the mutation and the dilution. This stop-gain mutation is likely the causative mutation for dilution within Jacob sheep.

Highlights

Coat color is suspected to be one of the first traits selected for in livestock species after domestication.Historically, selection in sheep has been for white wool, due to its ability to be dyed, as opposed to nonwhite wool
We identified 2572 small nucleotide variants within and surrounding MLPH (NC_019458.2: g.3383028-3478858)
The to present study knowledge has likely identified the causative mutation for dilute coat color within the

Summary

Introduction

Coat color is suspected to be one of the first traits selected for in livestock species after domestication.Historically, selection in sheep has been for white wool, due to its ability to be dyed, as opposed to nonwhite wool. Nonwhite wool comes in a variety of patterns and colors, which breeders can select to increase the revenue from wool sales. One such nonwhite coat color variation is dilution, which is commonly represented by lighter shades of color pigmentation. A dilute phenotype has been observed within the Jacob breed, often called lilac. This dilution results in the nonwhite portions of the wool appearing gray, rather than the traditional black. Based on pedigree analysis of the Jacob Sheep Breeders Association registry, the dilution is inherited and expressed in an autosomal recessive pattern [1]

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