Our ambitious project strives to contribute for the answering of that question by implementing the first long-term experimental evolution protocol to directly compare adaptation to ethanol stress of sexual versus asexual populations of a single-cell eukaryote (the yeast Schizosaccharomyces japonicus). Propagation of sexual versus clonal lines will unfold in parallel through at least 5000 generations, during which fitness will be periodically assayed. This will allow addressing in qualitative and quantitative terms fundamental questions in evolutionary biology:


        Do sexually propagating cells adapt faster to the environment than asexual?

        If yes, what is the dynamics of such differential adaptation over time?

        Can adaptation progress indefinitely, or will the supply of beneficial mutations diminish over time?


A novel aspect will be the use of Next Generation Sequencing (NGS) to access the dynamics of DNA mutations along the period of the protocol. The compiled repertory of DNA variations will represent a rich data set for addressing such important questions as:


Will genetic variations in cells undergoing meiosis be qualitatively and quantitatively different from those observed in mitotic cells?

        What is the TE dynamics in cells undergoing meiosis versus mitosis?

What is the panorama of variant types (substitutions, indels, chromosome rearrangements, exon shuffling, etc.) that underlie the adaptive landscape in sexual versus clonal lines?


In addition, adaptive evolution to ethanol stress in S. japonicus will allow posing the following questions:


What are the gene categories and biological functions under selective pressure by the ethanol stress?

How much such a protocol of adaptive evolution and recurrent meiosis can accelerate development of ethanol hyper-tolerant strains?


In summary, comparative genomics of sexually versus asexually evolving lines is a novel approach that will provide a new perspective for understanding the advantages of sexual reproduction. Please, learn more about the project by following the links above.



People involved: Dr. Ana Paula Jacobus