<p>Spo11 is a meiosis-specific protein in yeast that covalently binds to DNAdouble-strand breaks (DSBs) during the early stages of meiosis [<cite idref="PUB00007203"/>]. These DSBs initiate homologous recombination, which is required for chromosomal segregation and generation of genetic diversity during meiosis. Mouse and human homologues of Spo11 have been cloned and characterised. The proteins are 82% identical and share ~25% identity with other family members. Mouse Spo11 has been localised to chromosome 2H4, and human SPO11 to chromosome 20q13.2-q13.3, a region amplified in some breast and ovarian tumours [<cite idref="PUB00007203"/>].</p> <p>Similarity between SPO11 and archaebacterial TOP6A proteins points to evolutionary specialisation of a DNA-cleavage function for meiotic recombination [<cite idref="PUB00007204"/>]. Note that the yeast SPO11 protein shares far less similarity to other SPO11 proteins than the human and mouse homologues do to each other.</p> Meiotic recombination, Spo11