Submitted to: Fungal Genetics and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2003
Publication Date: N/A
Interpretive Summary: Mating in mushroom fungi is controlled by specific genes that evolve very rapidly. The rapid rate of evolutionary change in these sequences makes the process of isolating and studying mating genes in different species extremely difficult. This study demonstrates that the mating genes are located near a more slowly evolving gene, called mitochondrial intermediate peptidase (MIP), that is more easily detected than mating genes. A method is described that uses the physical proximity of MIP as a strategy for isolating the mating genes. This information will be used by scientists studying the biology of mushrooms and related fungi.
Technical Abstract: The high level of DNA polymorphism at the mating-type loci of mushroom fungi has made the cloning of mating-type genes difficult. As an alternative to strategies that employ sequence conservation to cloning, an approach utilizing conserved gene order could facilitate the cloning of A mating-type genes from mushroom fungi. It has been shown that a gene encoding a mitochondrial intermediate peptidase (MIP) is very close (<1 kbp) to the A mating-type locus of two model mushroom species. In this study, the cosegregation of MIP and the A mating-type locus was studied by genotyping progeny of seven additional mushroom species using degenerate PCR and genetic crosses. No evidence of any recombination between MIP and the A mating-type locus was detected among all seven species. Phylogenetic analysis of MIP sequences from diverse mushroom species agrees with the current organismal phylogeny, suggesting the sequences are generally orthologous.