title: Genetic mechanisms and constraints governing the evolution of correlated traits in drosophilid flies.
abstract: Some morphological traits differ greatly between related species, but it is not clear whether diversity evolves through changes in the same genes and whether similar, independent (that is, convergent) changes occur by the same mechanism. Pigmentation in fruitflies presents an attractive opportunity to explore these issues because pigmentation patterns are diverse, similar patterns have arisen in independent clades, and numerous genes governing their formation have been identified in Drosophila melanogaster. Here we show that both evolutionary diversification and convergence can be due to evolution at the same locus, by comparing abdominal pigmentation and trichome patterns and the expression of Bric-à-brac2 (Bab2), which regulates both traits in D. melanogaster, in 13 species representing the major clades of the subfamily Drosophilinae. Modifications of Bab2 expression are frequently correlated with diverse pigmentation and trichome patterns that evolved independently in multiple lineages. In a few species, Bab2 expression is not correlated with changes in pigmentation but is correlated with a conserved pattern of trichomes, indicating that this locus can be circumvented to evolve new patterns when a correlated trait is under different constraints.
authors.affiliation: Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin, 1525 Linden Drive, Madison, Wisconsin 53706, USA.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gompel
authors.forename: Sean B
authors.initials: SB
authors.lastname: Carroll
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004330:Drosophila / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics* / Q000502:physiology*; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C459600:BAB2 protein, Drosophila; D029721:Drosophila Proteins; D014157:Transcription Factors