Meiotic recombination protein DMC1/LIM15 homolog is a protein that in humans is encoded by the DMC1 gene. Meiotic recombination protein Dmc1 is a homolog of the bacterial strand exchange protein RecA. Dmc1 plays the central role in homologous recombination in meiosis by assembling at the sites of programmed DNA double strand breaks and carrying out a search for allelic DNA sequences located on homologous chromatids. The name "Dmc" stands for "disrupted meiotic cDNA" and refers to the method used for its discovery which involved using clones from a meiosis-specific cDNA library to direct knock-out mutations of abundantly expressed meiotic genes. The Dmc1 protein is one of two homologs of RecA found in eukaryotic cells, the other being Rad51. In budding yeast, Rad51 serves as a strand exchange protein in mitosis where it is critical for the repair of DNA breaks. Rad51 is converted to an accessory factor for Dmc1 during meiosis by inhibition of its strand exchange activity. Homologs of DMC1 have been identified in many organisms including divergent fungi, plants and mammals including humans. Discovery The DMC1 gene and protein were discovered in the budding yeast S. cerevisiae by Douglas Bishop when he was a postdoctoral fellow in the laboratory of Nancy Kleckner at Harvard University. Function The protein encoded by this gene is essential for meiotic homologous recombination. Genetic recombination in meiosis plays an important role in generating diversity of genetic information and facilitates the reductional segregation of chromosomes that must occur for formation of gametes during sexual reproduction. Like other members of the Rad51/RecA family, Dmc1 stabilizes strand exchange intermediates (Rad1/RecA-stretched DNA, or RS-DNA) in stretched triplets similar to B form DNA. Each molecule of the protein binds a triplet of nucleotides, and the strength of that binding, as assessed by the change in Gibbs free energy, can be assessed by the length of time that a labelled dsDNA probe with a short homologous sequence remains bound to a DNA containing a short region of homology to it. A study of this type has shown that a mismatch in any of the three positions at the end of a stretch of homology will not increase the length of time that the probe remains bound, and in Rad51 or RecA constructs an internal mismatch will cause a similar reduction in binding time. All of the enzymes are capable of "stepping over" a mismatch and continuing to bind the