Dynamic patterns of adaptive radiation.
Adaptive radiation is defined as the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage. When it occurs, adaptive radiation typically follows the colonization of a new environment or the establishment of a "key innovation," which opens new ecological niches and/or new paths for evolution. Here, we take advantage of recent developments in speciation theory and modern computing power to build and explore a large-scale, stochastic, spatially explicit, individual-based model of adaptive radiation driven by adaptation to multidimensional ecological niches. We are able to model evolutionary dynamics of populations with hundreds of thousands of sexual diploid individuals over a time span of 100,000 generations assuming realistic mutation rates and allowing for genetic variation in a large number of both selected and neutral loci. Our results provide theoretical support and explanation for a number of empirical patterns including "area effect," "overshooting effect," and "least action effect," as well as for the idea of a "porous genome." Our findings suggest that the genetic architecture of traits involved in the most spectacular radiations might be rather simple. We show that a great majority of speciation events are concentrated early in the phylogeny. Our results emphasize the importance of ecological opportunity and genetic constraints in controlling the dynamics of adaptive radiation.
Gavrilets
Sergey
S
Department of Ecology, University of Tennessee, Knoxville, TN 37996, USA. sergy@tiem.utk.edu
Vose
Aaron
A
D000220:Adaptation, Biological / Q000235:genetics*; D003198:Computer Simulation; D003710:Demography; D004777:Environment; D014644:Genetic Variation; D005828:Genetics, Population; D008962:Models, Theoretical; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D011157:Population Dynamics