Researchers Generate Whole Genome Map of Fruit Fly Genetic Recombination

For the first time, researchers at the Stowers Institute for Medical Research in Missouri, USA, have mapped where recombination occurs across the whole genome of the fruit fly Drosophila melanogaster. The result indicates that separate mechanisms position the two main kinds of recombination events, crossovers and non-crossovers.

Most genetic studies of recombination in Drosophila have focused either on a single chromosome arm or on groups of flies pooled together. In this study, the researchers wanted to determine how both crossovers and non-crossovers are distributed across all five major chromosomal arms of fruit flies.

Danny Miller, MD-PhD student at the University of Kansas Medical Center, mated two genetically distinct varieties of fruit flies, known to differ at roughly 500,000 different spots in their genetic code. He then sequenced the entire genomes of the resulting 196 progeny and wrote a custom computer program that could scan the 160 million bases of each fruit fly genome for evidence of recombination. The approach identified a total of 541 crossovers and 291 non-crossovers. Unlike crossovers, which are generally distributed over the distal two-thirds of the chromosome arms, the non-crossovers were spread uniformly among the five major chromosome arms. Non-crossovers formed in places where crossovers rarely do, and they popped up close together, in contrast to crossovers that respond to interference when they try to form near other crossovers.

For more details, read the news release at the Stowers Institute for Medical Research website.