Meiosis: Mind the gap

Scientists have now discovered that cells sometimes liberate DNA fragments at sites of paired, or double, DSBs © Franz Klein, Chromosomenbiologie, Universität Wien - Meiosis is a specialized cell division process required to generate gametes, the reproductive cells of an organism. During meiosis, paternal and maternal chromosomes duplicate, pair, and exchange parts of their DNA in a process called meiotic recombination. In order to mediate this exchange of genetic material, cells introduce double strand breaks (DSBs) into their chromosomal DNA. Scientists from the lab of Franz Klein from the Department of Chromosome Biology at the Max Perutz Labs, a joint venture of the University of Vienna and the Medical University of Vienna, have now discovered that cells sometimes liberate DNA fragments at sites of paired, or double, DSBs. Whilst this presents an obvious risk of germline mutations as a consequence of erroneous repair or of integration of fragments from elsewhere at break sites, it may also be a source of evolutionary diversity. Genetic information in humans is encoded in 23 chromosome pairs, where one pair consists of two slightly different copies or homologs. One is inherited from the father and one from the mother.