The evolution of recombination cold spots during speciation

2014-2016 ARC Discovery grant with Jan Engelstaedter

In the absence of geographic barriers, sexual reproduction between diverging populations is the greatest obstacle to the formation of new species. As diverging populations accumulate differences by the action of natural selection, genetic recombination resulting from sexual reproduction eliminates them. As a consequence, cases of speciation with gene flow such as sympatric or parapatric speciation have been considered improbable. This project will investigate novel hypotheses for the formation of new species in the face of gene flow, and will evaluate empirically their predictions using the groundsel Senecio lautus. Results derived from this investigation will provide novel insights into the old riddle of speciation with gene flow.

The genetics of replicated evolution. 

2012-2014 ARC Discovery grant

Evolution sometimes repeats itself. The recurrent origin of forms and species exists across kingdoms, but we remain largely ignorant about its genetic causes. Here we use native Australian daisies from the genus Senecio to uncover the molecular basis of the parallel evolution of prostrate and erect forms, and the repeated evolution of reproductive isolation between them. We combine novel population genomic approaches and classical genetics with field experiments to trace the genes responsible for these traits. Our results will provide fundamental information on the genetic basis of plant speciation driven by natural selection, thus helping to fill a gap in our understanding of how species originate and adapt to novel environments. 

Does divergent natural selection drive the early stages of speciation? 

2009-2011 ARC Discovery grant with Prof. Loren Rieseberg of UBC; A/Prof. Peter Mather of QUT. 

Speciation is the ultimate source of biodiversity.  Empirical evidence strongly implicates natural selection in speciation, yet the genetic and ecological mechanisms operating during this process remain unknown.  We will use a novel approach to provide one the first experimental reconstructions of the early stages of speciation, investigate how genes and ecology drive the process of divergence using experimental evolution in the wild, and use genomic tools to determine if parallel adaptation to different environments involves the same genes. Our study puts forward a comprehensive and novel approach to understand how genes and ecology drive speciation.

Speciation and the breakdown of coevolution during speciation. 2009-2009-2011 ARC Discovery grant with Dr. Eric Baack of Luther College.

Just as hosts and parasites evolve in step with each other, genes within the cell are also known to coevolve. Because populations can become geographically isolated and mutation is random, the coevolution of genes may take different evolutionary paths. Populations whose genes coevolve independently may become incompatible and incapable of interbreeding. We will test how novel nuclear and cytoplasmic genetic combinations in hybrids affect heredity, gene expression, and how coevolved genes affect hybrid fitness. This project will provide significant and innovative insights into the maintenance of boundaries between existing species.

© Daniel Ortiz Barrientos 2017