A 14-bp insertion in endothelin receptor B-like (EDNRB2) is associated with white plumage in Chinese geese

Lei Wang,Hehe Liu,Liang Li,Jiwen Wang,Hua He,Shengchao Ma,Yanying Li,Yang Xi,Lili Bai,Ahsan Mustafa,Han Chunchun

doi:10.1186/s12864-020-6562-8

Abstract

BackgroundGang goose is a native species with gray plumage in Sichuan, China. As a result of overhunting, the number of gray Gang geese has decreased dramatically. To keep the species from extinction, conservation work for Gang geese was undertaken. In the process of pure breeding of gray Gang geese, approximately 2% of the offspring of each generation were white. This study aims to explain the genetic mechanism of this phenomenon and provide reliable molecular markers for goose-related plumage color breeding.ResultsWe used the method of pooled whole genome sequencing and Fst (fixation statistics) to identify the differentiation degree of alleles between gray Gang geese and white Gang geese from their offspring. In this way, EDNRB2, a key gene that affects the migration of melanoblasts, was identified. Then, the transcriptome was sequenced for the two geese plumage color populations, and the DEGs (differentially expressed genes) were analyzed. The results indicated that EDNRB2, as a possible candidate gene, had a significantly differential mRNA expression. In addition, a 14-bp insertion (NW_013185915.1: g. 750,748–750,735 insertion. CACAGGTGAGCTCT) in exon 3 of EDNRB2 was analyzed and found to have a significant association between gray geese and Chinese white breeds (P = 0.00), while this mutation was not found in European geese. Meanwhile, the insertion was homozygous in all the white geese we detected and heterozygous in gray geese, indicating that this mutation is recessive. Furthermore, this 14-bp insertion leads to a frameshift mutation in the EDNRB2 coding region and nonsense-mediated mRNA decay.ConclusionOur study strongly suggests that the 14-bp insertion in exon 3 of the EDNRB2 gene is associated with the white plumage phenotype in Chinese geese. This study is the first to investigate the relationship between EDNRB2 and white plumage in geese.

Highlights

Gang goose is a native species with gray plumage in Sichuan, China
For the dominant white phenotype of chicken, sequence analysis showed that 9bp insertions in exon 10 of the Premelanosome protein (PMEL17) gene were completely correlated with the allele of dominant white traits
Twenty gray Gang geese and 20 white Gang geese were divided into two groups for genomic pooling sequencing

Summary

Introduction

Gang goose is a native species with gray plumage in Sichuan, China. As a result of overhunting, the number of gray Gang geese has decreased dramatically. Scientists have found that a sequence of avian retroviruses was inserted into intron 4 of the TYR gene and that this insertion can lead to recessive white traits in chickens This insertion results in the absence of exon 5 in transcriptional mRNA [7]. For the dominant white phenotype of chicken, sequence analysis showed that 9bp insertions in exon 10 of the PMEL17 gene were completely correlated with the allele of dominant white traits. This mutation led to a 3-aa insertion in the transmembrane domain of the PEML17 protein [8]. This mutation has an epistatic effect on other color-related loci [11]

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