THE MINISATELLITE MSB1, IN THE FUNGUS BOTRYTIS-CINEREA, PROBABLY MUTATES BY SLIPPAGE

A minisatellite was identified in the intron of the ATP synthase of th e filamentous fungus Botrytis cinerea, and it was named MSB1. This is the second fungal minisatellite described to date. Its 37-bp repeat un it is AT-rich, and it is found at only one locus in the genome. The in trons of 47 isolates of Botrytis species were sequenced. The number of tandem repeats varied only from 5 to 11, but there were many repeat v ariants. The structure of MSB1 is peculiar: the variants are in the sa me physical order in all individuals, and this order follows the most parsimonious tree. These original characteristics, together with a tot al lack of recombination between alleles of the flanking regions, sugg est that MSB1 probably mutates by slippage. MSB1 was found in the intr on of the ATP synthase of all of the Botrytis species analyzed, but th e repeat unit was not found in any other genus examined, including Scl erotinia, which is the genus closest to Botrytis.