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Research article - Peer-reviewed, 2021

Cis-acting mutation affecting GJA5 transcription is underlying the Melanotic within-feather pigmentation pattern in chickens

Li, Jingyi; Lee, Mi-Ok; Chen, Junfeng; Davis, Brian W.; Dorshorst, Benjamin J.; Siegel, Paul B.; Inaba, Masafumi; Jiang, Ting-Xin; Chuong, Cheng-Ming; Andersson, Leif

Abstract

Melanotic (Ml) is a mutation in chickens that extends black (eumelanin) pigmentation in normally brown or red (pheomelanin) areas, thus affecting multiple within-feather patterns [J. W. Moore, J. R. Smyth Jr, J. Hered. 62, 215-219 (1971)]. In the present study, linkage mapping using a back-cross between Dark Cornish (Ml/Ml) and Partridge Plymouth Rock (ml(+)/ml(+)) chickens assigned Ml to an 820-kb region on chromosome 1. Identity-by-descent mapping, via whole-genome sequencing and diagnostic tests using a diverse set of chickens, refined the localization to the genomic region harboring GJA5 encoding gap-junction protein 5 (alias connexin 40) previously associated with pigmentation patterns in zebrafish. An insertion/deletion polymorphism located in the vicinity of the GJA5 promoter region was identified as the candidate causal mutation. Four different GJA5 transcripts were found to be expressed in feather follicles and at least two showed differential expression between genotypes. The results showed that Melanotic constitutes a cis-acting regulatory mutation affecting GJA5 expression. A recent study established the melanocortin-1 receptor (MC1R) locus and the interaction between the MC1R receptor and its antagonist agoutisignaling protein as the primary mechanism underlying variation in within-feather pigmentation patterns in chickens. The present study advances understanding the mechanisms underlying variation in plumage color in birds because it demonstrates that the activity of connexin 40/GJA5 can modulate the periodic pigmentation patterns within individual feathers.

Keywords

melanotic; patterning; GJA5; gap junction protein; IBD mapping

Published in

Proceedings of the National Academy of Sciences of the United States of America
2021, Volume: 118, number: 41, article number: e2109363118
Publisher: NATL ACAD SCIENCES

    UKÄ Subject classification

    Animal and Dairy Science

    Publication identifier

    DOI: https://doi.org/10.1073/pnas.2109363118

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/114161