Meeting Abstract
50.1 Tuesday, Jan. 5 The genetic basis of modularity in the African cichlid mandible PARSONS, KJ*; MARQUEZ, E; COOPER, WJ; ALBERTSON, RC; Syracuse University; Florida State University; Syracuse University; Syracuse University kevpar66@gmail.com
Most organisms are comprised of anatomical units recognizable from their developmental origins, or function. An emerging area of interest to biologists involves understanding how organisms are partitioned into units or modules. Modularity suggests clusters of connectivity, whereby a module represents a unit that is tightly integrated but relatively independent from other such modules. The structure of this connectivity could have major evolutionary implications but until recently methods of quantitatively determining modularity have been elusive. Here we use recent advances in morphometrics to investigate modularity in the mandible of African cichlids from lake Malawi. The cichlid mandible exhibits an extraordinary level of diversity that is associated with a variety of ecological niches. Currently little is known about patterns of modularity that may exist in this adaptively important trait. Patterns of modularity could be especially important for determining the rate and direction of adaptive divergence in cichlids. We tested for patterns of modularity in members of the genus Labeotropheus, which consist of algae-scraping specialists, and Metriaclima, who are relative ecological generalists. We also assayed modularity in a genetic mapping panel of their F2 hybrids. We then extended our methods to produce an individual-based metric of modularity by selectively removing individuals from our analysis and recalculating a goodness of fit. This metric was used in a quantitative trait loci approach to map the genomic regions associated with modularity. This approached identified genomic regions specific to patterns of modularity in each group. This powerful set of techniques will be valuable for uncovering the genetic architecture of modularity, which may ultimately lead us to a greater understanding of its role in evolution.
