Variation is the essential raw material for evolution. Understanding how variation at the nucleotide level translates into phenotypic (morphological, behavioral) variation provides fundamental perspective on how evolution operates and organisms diversify. We are interested in knowing where new mutations appear and accumulate in the genome, in finding how and where in the genome reproductive isolation evolves, and in understanding regulation of gene networks and evolution of new phenotypes.
In addition to the five cichlid genomes sequenced at the Broad Institute, we have sequenced the genomes of four additional species of Neolamprologus in collaboration with colleagues at the CEES and the NSC in Oslo. These new genomes have provided considerable insight into how speciation progresses at the genome level and how the recombination landscape shapes the evolution of reproductive isolation and the rate of hybridization. We report some of the first empirical data that support the impacts of genome architecture, recombination landscapes and selection at linked sites on rates of introgression and differentiation. Relevant to understanding how speciation can progress in the face of gene flow, collinear chromosomal regions can be protected from gene flow and harbor incompatibility genes if they reside in lowly recombining regions, and coupling can evolve between non-physically linked genomic regions (chromosome centers in particular). Simultaneously, chromosome peripheries appear as more dynamic, evolvable regions where introgression is higher and adaptation polymorphisms can evolve.
These new genomes will also be of great utility for population RAD-tag sequencing of Neolamprologus done with colleagues at the CEES. Some exciting preliminary genome scan results indicate adaptive divergence between two Neolamprologus with several pigmentation candidates implicated.
Last updated: August 7th, 2018