Mutations in the melanocortin-1 receptor (MC1R) gene have no influence on the distinct patterns of melanic plumage found in the manakins of the genus Antilophia (Aves: Pipridae)

Abstract

The melanocortin-1 receptor gene is the most widely-used marker for the investigation of the genetic determination of melanic plumage patterns. Studies of a number of wild bird species have shown an association between non-synonymous mutations of the MC1R gene and the presence of melanic variants. The genus Antilophia (Pipridae) includes only two manakin species (A. galeata and A. bokermanni), which are distinguished primarily by the differences in the pattern of melanic coloration of the plumage of the mantle in the adult males. In A. galeata, this plumage is black, while in A. bokermanni, it is predominantly white. This study investigates the possible association between mutations of the MC1R marker and the variation in plumage coloration observed in the two species. The MC1R sequences of the two species was analyzed, and the observed nucleotide variation was compared. Six polymorphic sites were identified, representing seven distinct genotypes. Five of these polymorphic mutations were non-synonymous, but were not related to the different phenotypes. Neutral evolution and the absence of any systematic association between the variants of the MC1R and plumage coloration in the Antilophia species indicate that alternative mechanisms regulate the expression of the coloration of the plumage in the adult males.

Plumage polymorphism and variation in the melanocortin-1 receptor gene in the Fuscous Flycatcher, Cnemotriccus fuscatus (Wied, 1831)

“…1 2 2 2 7 3 7 7 1 4 6 7 1 2 6 9 0 3 4 7 8 1 2 5 3 5 9 5 8 2 2 3 3 6 6 8 7 5 8 4 3 8 6 7 8 3 (Farrell et al 2014) and the genus Antilophia (Luna et al 2018), our fi ndings reinforce the conclusion that this gene does not always play a role in the variation in plumage coloration found among populations or species. In this case, other genes or mechanisms may determine this variation, as observed in a number of birds (McLean & Stuart-Fox 2014).…”

“…Overall, our results reinforce the conclusion that understanding the evolution of plumage coloration in C. fuscatus with varying patterns of eumelanin/pheomelanin pigmentation requires a more profound investigation of the genes in the melanocortin pathway and their potential variation, as well as other loci and environmental factors. Unlike many other bird species (see e.g., Cheviron et al 2006, Corso et al 2013, Farrell et al 2014, Luna et al 2018, the variation in the plumage coloration of C. fuscatus does not appear to be related to mutations of the MC1R gene.…”