Use it or lose it?

This post is a guest contribution by Dr. Levi Morran, NIH postdoctoral fellow at Indiana University. Levi studies the role that both coevolutionary relationships and mating systems play in shaping evolutionary trajectories. His research using experimental coevolution to test the Red Queen hypothesis recently appeared in Science and was featured on NPR and the BBC.

The 40 Year-Old Virgin movie poster

The 40 Year-Old Virgin

In the movie, The 40 Year Old Virgin, Steve Carell’s character (the title character) asks a sex education instructor, “Is it true that if you don’t use it, you lose it?” Given the context, I’ll allow you to put the pieces together and figure out just what he was referencing with the question. But, the phrase “use it or lose it” is quite catchy isn’t it?

Surprisingly, the phrase is thought to have some relevance in the field of evolutionary genetics, particularly regarding bacterial genomes. You see, widespread gene loss and genome reduction has been observed in some strains of bacteria, particularly those that specialize in certain environments (Cramer et al. 2011; Ernst et al. 2003; Smith et al. 2006). But, how and why do bacteria “lose it”, and do they lose it because they don’t use it?

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