Gene expression in male and female stickleback from populations with convergent and divergent throat coloration

• Published in: Ecology and evolution Vol. 12; no. 5; pp. e8860 - n/a
• Main Authors: McKinnon, Jeffrey S., Newsome, William Burns, Balakrishnan, Christopher N.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.05.2022; John Wiley and Sons Inc; Wiley
• Subjects: Behavioural Ecology; carotenoid; Carotenoids; Color; Coloration; Convergence; Ecological Genetics; Evolution; Females; Gender differences; Gene expression; Genes; Genetic diversity; Genomes; Genomics; Hypotheses; Males; Population; Populations; Quantitative genetics; Quantitative trait loci; Sexes; Sexual dimorphism; stickleback; Throats; British Columbia Canada; Canada; California; United States > US; carotenoid; stickleback; gene expression; sexual dimorphism
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.8860

Understanding of genetic mechanisms underlying variation in sexual dichromatism remains limited, especially for carotenoid‐based colors. We addressed this knowledge gap in a gene expression study with threespine stickleback. We compared male and female throat tissues across five populations, including two in which female red coloration has evolved convergently. We found that the expression of individual genes, gene ontologies, and coexpression networks associated with red female color within a population differed between California and British Columbia populations, suggesting differences in underlying mechanisms. Comparing females from each of these populations to females from populations dominated by dull females, we again found extensive expression differences. For each population, genes and networks associated with female red color showed the same patterns for males only inconsistently. The functional roles of genes showing correlated expression with female color are unclear within populations, whereas genes highlighted through inter‐population comparisons include some previously suggested to function in carotenoid pathways. Among these, the most consistent patterns involved TTC39B (Tetratricopeptide Repeat Domain 39B), which is within a known red coloration QTL in stickleback and implicated in red coloration in other taxa. Understanding of genetic mechanisms mediating variation in sexual dichromatism remains limited, especially for carotenoid‐based colors. Comparing gene expression in skin tissue from five populations of stickleback, including two in which female red coloration has evolved convergently, we found extensive inter‐population differences in the genes showing red‐correlated expression in females. Nevertheless, TTC39B, which has been suggested to mediate carotenoid‐based coloration in several taxa and is located within a stickleback pigmentation QTL, was consistently associated with red throat color.