![]() ![]() In euascomycetes, there is most commonly a single MAT locus (termed MAT1) ( 39). These are located within the genome at mating-type ( MAT) loci and determine mating compatibility and incompatibility ( 3, 7). One key factor governing the sexual reproductive mode in fungi is the presence or absence of so called mating-type ( MAT) genes. fumigatus would provide researchers with a powerful tool to analyze the genetics of pathogenicity in this prevalent mold and would be informative for an understanding of the population biology of the species and disease management ( 9). The ability to perform sexual crosses with A. It is hoped that studies may provide insights into the genetic basis of asexuality and possibly allow mating to be realized by supposedly asexual species. A key challenge in present research is to understand the genetic changes that underlie such shifts in reproductive modes. Close relationships between predominantly asexual and readily sexually recombining species such as these are common among fungi ( 1, 2, 5, 19, 23, 37). fischeri has a known sexual cycle and thus may reproduce by both asexual and sexual means ( 14, 26). fischeri has also been documented as an invasive opportunistic pathogen ( 4, 24). fumigatus is the most common cause of invasive aspergillosis infection in humans ( 8, 22) and is only known to reproduce by asexual means involving the production of masses of mitotic conidiospores. The results are also discussed in relation to their significance in indicating that heterothallism may be ancestral within the Aspergillus section Fumigati.Īspergillus fumigatus and Neosartorya fischeri are two closely related euascomycete molds (Eurotiomycetes, Pezizomycotina) in the genus Aspergillus, subgenus Fumigati, section Fumigati ( 12, 33, 36, 42). These results demonstrate a novel means involving the segmental translocation of a chromosomal region by which the ability to undergo self-fertilization may be acquired. The sequence upstream of MAT2 contained numerous candidate transposase genes. fumigatus MAT locus region, but no such long-range conservation in the N. ![]() Genome comparisons revealed synteny over at least 23,300 bp between the N. Partial copies of APN1 and SLA2 were also found bordering the MAT2 locus, but these copies bore the genetic hallmarks of pseudogenes. Complete copies of putative APN1 (DNA lyase) and SLA2 (cytoskeleton assembly control) genes were found bordering the MAT1 locus. ![]() However, unlike those in many homothallic euascomycetes (Pezizomycotina), the genes were not found adjacent to each other and were termed MAT1 and MAT2 to recognize the presence of distinct loci. Both putative alpha- and high-mobility-group-domain MAT genes were found within the same genome, providing a functional explanation for self-fertility. Degenerate PCR and chromosome-walking approaches were used to identify mating-type ( MAT) genes and flanking regions from the homothallic (sexually self-fertile) euascomycete fungus Neosartorya fischeri, a close relative of the opportunistic human pathogen Aspergillus fumigatus. ![]()
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