Genetic mapping of the female mimic morph locus in the ruff

Lindsay L Farrell,David B Lank,Susan B Mcrae,Terry Burke,Jon Slate

doi:10.1186/1471-2156-14-109

Lindsay L Farrell, David B Lank + Show 3 more

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https://doi.org/10.1186/1471-2156-14-109

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Abstract

BackgroundRuffs (Aves: Philomachus pugnax) possess a genetic polymorphism for male mating behaviour resulting in three permanent alternative male reproductive morphs: (i) territorial ‘Independents’, (ii) non-territorial ‘Satellites’, and (iii) female-mimicking ‘Faeders’. Development into independent or satellite morphs has previously been shown to be due to a single-locus, two-allele autosomal Mendelian mode of inheritance at the Satellite locus. Here, we use linkage analysis to map the chromosomal location of the Faeder locus, which controls development into the Faeder morph, and draw further conclusions about candidate genes, assuming shared synteny with other birds.ResultsSegregation data on the Faeder locus were obtained from captive-bred pedigrees comprising 64 multi-generation families (N = 381). There was no evidence that the Faeder locus was linked to the Satellite locus, but it was linked with microsatellite marker Ppu020. Comparative mapping of ruff microsatellite markers against the chicken (Gallus gallus) and zebra finch (Taeniopygia guttata) genomes places the Ppu020 and Faeder loci on a region of chromosome 11 that includes the Melanocortin-1 receptor (MC1R) gene, which regulates colour polymorphisms in numerous birds and other vertebrates. Melanin-based colouration varies with life-history strategies in ruffs and other species, thus the MC1R gene is a strong candidate to play a role in alternative male morph determination.ConclusionTwo unlinked loci appear to control behavioural development in ruffs. The Faeder locus is linked to Ppu020, which, assuming synteny, is located on avian chromosome 11. MC1R is a candidate gene involved in alternative male morph determination in ruffs.

Highlights

Ruffs (Aves: Philomachus pugnax) possess a genetic polymorphism for male mating behaviour resulting in three permanent alternative male reproductive morphs: (i) territorial ‘Independents’, (ii) non-territorial ‘Satellites’, and (iii) female-mimicking ‘Faeders’
Development into independent or satellite morphs has been previously shown to be due to a genetic polymorphism consistent with a single-locus, two
No linkage was detected between the Satellite and Faeder loci, and the Satellite locus was unlinked to any other marker in twopoint analysis

Summary

Introduction

Ruffs (Aves: Philomachus pugnax) possess a genetic polymorphism for male mating behaviour resulting in three permanent alternative male reproductive morphs: (i) territorial ‘Independents’, (ii) non-territorial ‘Satellites’, and (iii) female-mimicking ‘Faeders’. Ruffs (Philomachus pugnax) possess three distinct permanent alternative male reproductive morphs that differ in territorial lekking behaviour, plumage colour, and size: dark-plumed territorial ‘Independents’, white-plumed non-territorial ‘Satellites’ and small female mimic ‘Faeders’ that lack display plumage and behaviour [4,5,6,7]. The white-plumed satellites do not hold territories, are rarely aggressive, and are actively courted into co-displaying on courts held by independents, apparently due to female preference for male-male cooperation on leks [4,6,7,13,14] and a high rate of polyandry [15] In contrast to both classes of ornamented males, faeder males grow breeding plumage that is similar to that of females–lacking display feathers–and aggregate close to displaying males to ‘sneak’ copulations with females and interfere with copulation attempts by other males ([5]; Lank et al unpublished) (Figure 1). Normal-sized females carrying the dominant Satellite allele can be identified from the phenotype ratios of their male offspring when mated to independent males, and/or confirmed with observations of behaviour and ornamental plumage growth when implanted with testosterone [9]

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