Molecular evolution in yeast: Role of chromosomal inversions and translocations in speciation, adaptation and gene expression

Abstract

Species belonging to the Saccharomyces 'sensu stricto' group present a good model forstudying evolution due to their genetic versatility and availability of genomic data.Chromosomal rearrangements play a very important role in evolution of eukaryotes as wellas prokaryotes as they can affect phenotypic characteristics and modes of speciation. Innature these rearrangements are most likely caused by highly mobile genetic elements,such as retrotransposons. Karyotypic changes can cause alterations in gene transcriptioncausing genomic instabilities by inactivating or over-expressing particular genes. Only fewstudies looked at the importance of chromosomal rearrangements and their role on globaland local gene expression.The aim of this PhD project is to investigate the impact of chromosomal inversions andtranslocations on fitness adaptation, gene expression and speciation. I first demonstratedthat a single gene inversion (of DAL2) within a co-expressed gene cluster can cause analteration of the expression of inverted gene as well as the neighbouring genes, ultimatelyleading to a phenotypic change. I also showed that small and large size pericentric andparacentric inversions do not always alter the gene expression and in general have noeffect on growth rate. It was also shown that effect of large inversion on gene expression isnot always localized within the inversion but occurs globally. Finally, it is demonstratedthat chromosomal translocations can be responsible for the reproductive isolation ofSaccharomyces paradoxus and Saccharomyces cariocanus.

Date of Award	1 Aug 2012
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Daniela Delneri (Supervisor)