MITOCHONDRIAL-DNA INHERITANCE IN SEXUAL CROSSES OF PLEUROTUS-OSTREATUS

The inheritance of mitochondrial DNA (mtDNA) in sexual crosses was inv estigated to expand our understanding of the large genetic divergence in mtDNAs among natural populations of the higher basidiomycete Pleuro tus ostreatus. Reciprocal crosses were made between compatible monokar yons with distinguishable mtDNA restriction fragment length polymorphi sms (PFLPs). Almost all of the dikaryons produced by these crosses had mtDNA genotypes from one of the parental monokaryons. However, for di karyons isolated from the junction-zone of crossed monokaryons, recomb inant mitochondrial genomes commonly appeared. These results showed th at P, ostreatus mtDNA can be inherited biparentally, via mtDNA recombi nation, as well as uniparentally. Further, it was suggested that mtDNA recombination may be an important source of variation in mitochondria l genomes among natural populations of P. ostreatus.