Meeting Abstract

33.3  Sunday, Jan. 5 08:30  Pax3 and the genetic basis of variation in levels and integration of pigmentation in cichlid fishes ALBERTSON, RC*; POWDER, KE; HU, Y; COYLE, KP; ROBERTS, RB; PARSONS, KJ; UMass; UMass; UMass; NCSU; NCSU; Univ. Glasgow albertson@bio.umass.edu

Variation in pigmentation type and levels is a hallmark of myriad evolutionary radiations, and biologists have long been fascinated by the factors that promote and maintain variation in coloration across populations. Despite this interest, however, little is known about the underlying genetic basis for continuous variation in vertebrate coloration. We examined this question in cichlid fishes, which offer a vast diversity of pigmentation patterns that have evolved in response to both natural and sexual selection. Specifically, we crossed two divergence species to generate an F2 mapping population that exhibited extensive variation in pigmentation levels and patterns. Our experimental design is unique and robust in that it combines traditional QTL analysis with population genomics, which allowed us to move efficiently from QTL interval to candidate gene. In total, we detected 41 QTL and 13 epistatic interactions that underlie melanophore and xanthophore based coloration. We also identified 2 QTL and 1 interaction for variation in the magnitude of integration among these color traits. This finding is notable as there are marked differences, both within and between species, with respect to the complexity of expressed pigmentation patterns. While certain populations are characterized by more uniform “integrated” color patterns, others exhibit many more degrees of freedom with respect to the distribution of color “modules” across the fins and flank. Our data reveal, for the first time, a genetic basis for this difference. Finally, we provide strong support for several candidate genes underlying these QTL, including pax3, a know mediator of vertebrate coloration.