Spreading good news

Abstract

Gene conversion has a central role in the evolutionary fine-tuning of regulatory elements in the fruit fly Drosophila miranda.

Keywords: Drosophila miranda; evolutionary biology; genomics; non-allelic gene conversion; regulatory networks; transposable elements.

Figure 1.. Beneficial mutations can spread through a population both ‘vertically’ and ‘horizontally’.

Consider a hypothetical population with 10 individuals, each with a single chromosome that has four sites (open circles). (A) When beneficial mutations (red circles) are only passed ‘vertically’ between generations, the best possible outcome (shown in bottom dashed circle) is for all the individuals in the population to eventually have the beneficial mutation at the site where it appeared (i.e., the leftmost of the four circles). (B) However, when horizontal events (blue arrows) are involved, it is possible that an individual (marked with a star) can have the beneficial mutation at all four sites. Over time, the ‘vertical’ spread and natural selection can make it possible for all the individuals in the population to have the beneficial mutation at all four sites (not shown). These horizontal events could be the movement of a transposable element or, as Ellison and Bachtrog report, gene conversion.