The Evolution of Sex: Experimental Evolution and Population Ecology with Levi Morran

In one line of research, Professor Levi Morran observes the coevolution of C. elegans strains and microbial pathogens through population level biology to ask how and why sex evolved and why it is maintained. This is part of his overall research into how genetics and evolution affect the interaction of hosts and microbes. In this podcast, he explores

• Why scientists are curious about how hosts establish interactions with their microbes and what that looks like, evolutionary speaking;
• What advantages comes with his lab's method of experimental evolution and where on the continuum it lies in relation to evolution theory, and
• What significant results developed with their experiment comparing self-fertilizing reproduction versus sexual reproduction in the presence of pathogens.

Levi Morran is an assistant professor of biology at Emory University and is interested in factors affecting adaptive evolution. His lab utilizes experimental evolution, which means they perform evolution experiments in real time with genetics biology and evolution biology. They mostly use particular strains of C. elegans, which go through several generations quite rapidly. He explains this with a concrete example: when his lab explored the antagonistic interactions between a host and microbes and the influence of the evolution of sex, they set up populations of C. elegans that would produce sexually and through self-fertilization. They found that the self-fertilizing populations did not adapt to the pathogens and mostly died out. He explains why he thinks this happened and how they may explore this further.

He also explores general benefits of experimental evolution and the advantages it offers researchers such as the ability to control and spin factors that can address very specific questions in certain conditions. He adds that conditions in nature are quite different, yet these experimental studies can point evolution theory in helpful directions. In addition, he explains the level of considerations an experimental evolution study must undertake, from seeking and using specific strains of nematodes fitting what the experimental questions ask, to unlocking characteristics in those nematodes to produce populations that will undergo, for example, sexual reproduction. He also addresses issues of microbiomes in nature versus the lab and questions regarding epigenetics.

For more, see his lab's website: wormlab.wordpress.com. Available on Apple Podcasts: apple.co/2Os0myK