Difference in Plumage Color Used in Species Recognition between Incipient Species Is Linked to a Single Amino Acid Substitution in the Melanocortin‐1 Receptor

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. abstract: Many studies demonstrate that differences in mating signals are used by incipient species in recognizing potential mates or sexual competitors (i.e., species recognition). Little is known, however, about the genetic changes responsible for these differences in mating signals. Populations of the Monarcha castaneiventris flycatcher vary in plumage color across the Solomon Islands, with a subspecies on Makira Island having chestnut bellies and blue-black upper parts (Monarcha castaneiventris megarhynchus) and a subspecies on neighboring satellite islands being entirely blue-black (melanic; Monarcha castaneiventris ugiensis). Here we show that a single nonsynonymous point mutation in the melanocortin-1 receptor (MC1R) gene is present in all melanic birds from one island (Santa Ana) but absent in all chestnut-bellied birds from Makira Island, implicating this mutation in causing melanism. Birds from a second satellite island (Ugi) do not show the same perfect association between this MC1R variant and plumage color, suggesting an alternative mechanism for melanism on this island. Finally, taxidermic mount presentation experiments in Makira (chestnut) and Santa Ana (melanic) suggest that the plumage difference mediates species recognition. Assuming that the signals used in species recognition are also used in mutual mate choice, our results indicate that a single amino acid substitution contributes to speciation.

Mutations in different pigmentation genes are associated with parallel melanism in island flycatchers

“…partial melanic): three individuals from Makira and three individuals from Santa Ana. Birds were caught with mist nets then measured, tagged, blood-sampled and released as part of a long-term study [21,22]. Genomic DNA was extracted from blood samples using standard protocols (DNEasy DNA Extraction Kit, Qiagen, Valencia, CA, USA).…”

“…Our study system comprises geographically isolated populations with nearly fixed phenotypes but limited population genetic structure [22] (see the electronic supplementary material, figure S1). We, therefore, used two complementary approaches to recover potential candidate genes for plumage colour and to infer the evolutionary processes that mediate the differences in plumage colour across islands: (i) a genome-wide association study (GWAS), which is more appropriate for studies of groups with little background, genetic structuring; and (ii) an F ST outlier test, which is more appropriate for studies of distinct populations.…”

“…Phylogenetic analyses of the M. castaneiventris complex indicate that M. c. megarhynchus and M. c. ugiensis form a separate, well-supported clade that is sister to the other M. castaneiventris subspecies [21]. Neither taxon, however, is reciprocally monophyletic owing to gene flow between islands and the retention of ancestral polymorphisms, reflecting their recent divergence [22,23]. More recent phylogenomic analyses, however, suggest that the melanic population of Santa Ana is sister to the chestnut-bellied Figure 1.…”

The phylogeography of red and yellow coppersmith barbets (Aves: Megalaima haemacephala)

“…Intra-specific variation can occur between age classes, sexes or within and between populations. Changes or differences in plumage among individuals and populations can be the starting point of sexual selection, incipient speciation or the evolution of sexual dimorphism (Galeotti et al, 2003;Roulin, 2004;Gray and McKinnon, 2007;Uy et al, 2009;Gonzalez-Voyer et al, 2013). Different color morphs have been linked to different life history characters, immune system function, and behavior (McKinnon and Pierotti, 2010).…”

“…Different color morphs have been linked to different life history characters, immune system function, and behavior (McKinnon and Pierotti, 2010). In many cases where the morphs are mixed within populations, such as the Gouldian finch (Pryke, 2007), the different morphs mate assortatively, and thus may represent incipient sympatric speciation (Gray and McKinnon, 2007;Uy et al, 2009). In most cases it is unclear if the morphs evolved in sympatry or allopatry, if they arose once and spread or had multiple origins within a species.…”