Correlation of Genetic and Physical Maps at the A Mating-Type Locus of Coprinus cinereus

Abstract

The A mating type locus of Coprinus cinereus is remarkable for its extreme diversity, with over 100 different alleles in natural populations. Classical genetic studies have demonstrated that this hypervariability arises in part from recombination between two subloci of A, alpha and beta, although more recent population genetic data have indicated a third segregating sublocus. In this study, we characterized the molecular basis by which recombination generates nonparental A mating types. We mapped the frequency and location of all recombination events in two crosses and correlated the genetic and physical maps of A. We found that all recombination events were located in 6 kb of noncoding DNA between the alpha and beta subloci and that the rate of recombination in this noncoding region matched that generally observed for this genome. No recombination within gene clusters or within coding regions was observed, and the two alpha and beta subloci described in genetic analyses correlated with the previously characterized alpha and beta gene clusters. We propose that pairs of genes constitute both the sex determining and the hereditary unit of A.

Molecular diversity maintained by long-term balancing selection in mating loci defines multiple mating types in fungi

“…Rearrangements in both MAT loci might be an important factor suppressing recombination in these genes. On the contrary, the gene order conservation of the alpha complex does not completely suppress recombination, in accordance with evidence of ongoing recombination between mating genes (Lukens et al . 1996) and their flanking genes in other fungal organisms (James 2007).…”

“…Rearrangements in both MAT loci might be an important factor suppressing recombination in these genes. On the contrary, the gene order conservation of the alpha complex does not completely suppress recombination, in accordance with evidence of ongoing recombination between mating genes [58] and their flanking genes in other fungal organisms [59]. Our observations highlight how studying a high number of specimens of the same species, as we have done here for the first time in fungal literature, can unravel previously underestimated mechanisms that generate diversity in mating genes.…”

Haplotype-Resolved Genome Analyses Reveal Genetically Distinct Nuclei within a Commercial Cultivar of Lentinula edodes

“…However, there are often several pairs of HD and P/R loci within individual genomes in Basidiomycota. In Coprinopsis cinerea, studies have reported that the HD locus is multiallelic and composed of two subloci [67,68]. However, different alleles appearing at only one sublocus is usually sufficient to induce the development and maintenance of the dikaryon.…”

Analise genomica do sistema mating type de Crinipellis perniciosa, fungo causador da vassoura-de-bruxa em Theobroma cacao

“…O sub locus A alfa contém um par de genes, a1 e a2, que codificam as proteínas HD1 e HD2, respectivamente. O sub locus A beta contém dois pares de genes, b1 e b2 e d1 e d2, que também codificam pares das proteínas HD1 e HD2, respectivamente (Kues 1992;Kües 1993;Lukens 1996).…”

“…Como em S. commune, há também em C. cinereus genes não ligados a mating, mas que flanqueiam o locus A. Um destes é o gene mip que codifica uma peptidase intermediária mitocondrial uma metalo-endopeptidase (Casselton et al 1995; Isaya et al 1995), que flanqueia o sub locus Aalfa. Flanqueando o sub locus Abeta tem o gene beta-fg, um curto gene conservado de função desconhecida(Kues 1992;, e o gene ade-8(Day 1960;Lukens 1996). Outro gene é o pab-1, gene necessário para a produção de ácido para-aminobenzóico (paba), que flanqueia entre o sub loci Aalfa e Abeta(Rapper 1966;Giasson et al 1989;Mutasa et al 1990).…”