Mutability of microsatellites developed for the ant Camponotus consobrinus

Five highly polymorphic (GA)(n) microsatellite loci are reported for the fo rmicine ant Camponotus consobrinus. The occurrence of many nests with a sim ple family structure enabled a search for new mutations, 11 of which were f ound from 3055 informative typings. These mutations were not randomly distr ibuted across loci, 10 of them occurring at the locus Ccon70. The spectrum of mutations across alleles at Ccon70 was also nonrandom, with all of them occurring in alleles in the upper half of the allele size distribution. Six of the Ccon70 mutations decreased allele size. The mutations observed fit the stepwise mutation model well, i.e. mutations could always be assigned t o an allele which differed in size from them by one repeat unit. The parent al origins of the Ccon70 mutations were established and appear more female biased than vertebrate mutations, significantly so compared with human haem ophilia A and primate intron mutations. This result may indicate that the l ack of meiosis in males (which are haploid in ants) reduces the mutation ra te in that sex relative to species in which both sexes are diploid.