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Variation in Genetic Mechanisms for Plumage Polymorphism in Skuas (Stercorarius)
Kirstin Janssen1,2, Jan Ove Bustnes3, Nicholas I Mundy4
1Department of Natural Sciences, Tromsø University Museum, NO-9037 Tromsø, Norway.
The Journal of Heredity
|August 3, 2021
Summary
Evolutionary plumage color changes in skuas are not always repeatable at the genetic level. Different genes influence coloration, suggesting unique genetic architectures for sex-biased traits.
Area of Science:
- Evolutionary biology
- Genetics
- Animal coloration
Background:
- Plumage coloration is a rapidly evolving trait, making it useful for studying evolutionary repeatability.
- Skuas exhibit plumage polymorphism, with previous research linking it to the melanocortin-1 receptor (MC1R) gene in two species.
Purpose of the Study:
- To investigate the repeatability of ventral plumage coloration evolution in skuas.
- To identify the genetic basis of plumage polymorphism in the south polar skua (S. maccormicki).
Main Methods:
- Genetic analysis of the melanocortin-1 receptor (MC1R) locus.
- Examination of the tyrosinase-related protein 1 (TYRP1) locus, a Z-linked candidate gene.
- Comparison of genetic findings across different skua species.
Main Results:
- Plumage polymorphism in south polar skuas is not associated with coding variation at MC1R.
- No association was found between polymorphism and variation at the TYRP1 locus in south polar skuas.
- Convergent evolution of plumage polymorphism in skuas is only partially repeatable at the genetic locus level.
Conclusions:
- The genetic underpinnings of plumage polymorphism in skuas are not entirely consistent across species.
- Phenotypic variation, such as sex-biased coloration in south polar skuas, may dictate unique genetic architectures.
- Evolutionary repeatability of coloration is influenced by both the genetic locus and the nature of the phenotypic trait.
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