Related Experiment Video
Updated: Jun 13, 2026

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern
Published on: March 8, 2020
Sequence polymorphism in candidate genes for differences in winter plumage between Scottish and Scandinavian Willow
Pontus Skoglund1, Jacob Höglund
1Department of Population Biology and Conservation Biology, Uppsala University, Uppsala, Sweden. pontus.skoglund@ebc.uu.se
Background:
Population variation in the degree of seasonal polymorphism is rare in birds, and the genetic basis of this phenomenon remains largely undescribed. Both sexes of Scandinavian and Scottish Willow grouse (Lagopus lagopus) display marked differences in their winter phenotypes, with Scottish grouse retaining a pigmented plumage year-round and Scandinavian Willow grouse molting to a white morph during winter. A widely studied pathway implicated in vertebrate pigmentation is the melanin system, for which functional variation has been characterised in many taxa.
Methodology/Principal Findings:
We sequenced coding regions from four genes involved in melanin pigmentation (DCT, MC1R, TYR and TYRP1), and an additional control involved in the melanocortin pathway (AGRP), to investigate the genetic basis of winter plumage in Lagopus. Despite the well documented role of the melanin system in animal coloration, we found no plumage-associated polymorphism or evidence for selection in a total of approximately 2.6 kb analysed sequence.
Conclusions/Significance:
Our results indicate that the genetic basis of alternating between pigmented and unpigmented seasonal phenotypes is more likely explained by regulatory changes controlling the expression of these or other loci in the physiological pathway leading to pigmentation.
Related Concept Videos
Complementation Tests
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Epistasis
Position-effect Variegation
Genetics of Speciation
Formation of Species

