Alladi Ramakrishnan Hall

Genes and Speciation: What can we learn from yeast

Krishna B. S. Swamy

Institute of Molecular Biology, Academia Sinica, Taipei,Taiwan.

Dobzhansky-Muller incompatibilities represent reciprocal-sign epistasis between interspecific alleles and are widely accepted as a major driver of postzygotic reproductive isolation. Although incompatibilities involving multiple genomic loci with weak effects (weak incompatibilities) have been frequently observed, the underlying mechanistic evidence has remained elusive. In this presentation, I will first show that introgressed hybrids of closely related yeast species suffer from proteotoxic stress caused by weak incompatibilities, which has dire consequences on their fitness and sporulation rate. I will elaborate on the computational and experimental approaches that were used to demonstrate that weak incompatibilities causes impaired multi-protein complex assembly resulting in imbalanced protein homoeostasis (i.e., proteotoxic stress) and represents a general source of hybrid breakdown. I will conclude by presenting my research plans for the next 5-7 years. Although, hybridization between reproductively isolated species seem to be discouraging, hybrids are frequently found in the wild and hybridization is known to be an important source of biodiversity. Interspecific hybrids also have immense economical value. For example, our current agro-industry is in fact driven by such hybrids. This raises the conundrum: if hybrids are usually inviable or sterile, then under what conditions can new lineages evolve after hybridization? In this part of the talk, I will propose computational and experimental strategies built on the experience gained during my PhD and postdoctoral work to address this big question.