Abstracts (first author)
Rapid genomic divergence across the speciation continuum
A new genomic theory for population divergence is presented predicting rapid speciation-with-gene-flow when a critical threshold of divergently selected loci is reached. The theory is explored as a possible explanation for recent findings from several model speciation systems implying that extensive genetic differentiation may characterize even early stages of ecological divergence. In particular, patterns of genomic divergence among Rhagoletis fruit flies - a model for ecological speciation-with-gene flow via sympatric host plant shifting - are examined as a test for the theory. If true, the theory provides a means to account for how gradual adaptive change, as epitomized by Darwin, can be reconciled with observations of sudden bursts of speciation, as occur during adaptive radiations, without the need to invoke macroevolutionary processes.