Genomics of hybrid speciation in pines
Hybridization is an important force in plant evolution. It can quickly create evolutionary novelties that promote adaptation and speciation by transferring beneficial traits between species. The ultimate goal of speciation research is to establish the link between phenotype and causal mutations and genome architecture to track adaptive changes that facilitated the formation of new species. Linking genome-wide variation with phenotype in an organism ultimately requires genome sequence information, and as a result, much of the progress in this field to date has been limited to genetic model organisms. However, the recent explosion in affordable and high-throughput technologies for next generation sequencing means that genome-wide studies in non-model organisms are now much more achievable, and several studies have demonstrated that novel functional genomic insights can be gained for species without fully sequenced genomes. In this project, we use genomic tools to investigate the genomic patterns of divergence and admixture in the hybrid pine Pinus densata, which is adapted to a novel habitat on the Tibetan Plateau. The origin of P. densata dates back to the uplift of the plateau 8-10 mln years ago, and some populations have been in isolation from gene exchange for 3 mln years. Its ancient history and unique adaptation offer a rare opportunity to study the genetic basis of speciation. We shall conduct a comparative analysis including populations of the ancient hybrid, and man-made hybrids. We shall utilize a time-effective method for generating population genomic data. The method uses double restriction enzymes and PCR amplification to generate a library of fragments that can be sequenced with a high level of multiplexing. This analysis aims at gaining a comparative view on: • genome-wide patterns of divergence in the hybrid complex. • genome–wide patterns of admixture in different hybrid lineages, and how that evolves as the speciation proceeds. • association maps between phenotype and genetic loci.