Taming Genetic Recombination

Scientists at the Institut National de la Recherche Agronomique in Versailles-Grignon have deciphered the mechanism of how plant promotes recombination. Published in the online edition of Science, the study focused on a mutant of Arabidopsis thaliana, the zmm mutants. The mutant exhibits very low number of chromosome crossovers, a poor distribution of chromosomes to its gametes and a marked reduction in its fertility.

Among this mutant population, the team searched for new mutants that would be capable of restoring crossovers and fertility. They found a mutant they named fancm that produce the enzyme FANCM, a member of the helicase family (enzymes that promotes the unwinding and separation of the two strands of the DNA double helix). This new mutant when crossed with zmm mutants restores the crossover ability of the mutant.

A single mutation of the FANCM gene can also lead to a tripling in the number of crossovers without having any effect on the fertility or health of the plant. This research work opens promising perspectives in cultivated plants where an increase in genetic recombination during reproduction, via regulation of the number of crossovers, would provide access to unknown combinations of traits of interest - an extremely important phenomenon useful for the plant breeders. 

For details of the story, see http://www.international.inra.fr/press/genetic_recombination_regulation