D. hansenii is homothallic, with a fused mating locus [ 49, 50].
When GFP was fused to the mating factor α (MFα) prepro-leader sequence secretion signal derived from the precursor of the Saccharomyces cerevisiae MFα (Kurjan and Herskowitz, 1982), there was no marked effect on the colony forming unit (CFU) capacity.
For example, in the genus Cochliobolus while several species in this genus are outcrossing, most of the homothallic species in this genus contain either fused or linked compatible mating genes [51].
Haploid cells of opposite mating types are fused to form a diploid cell and immediately undergo meiosis and sporulation.
Thus, as P. stipitis and D. hansenii (Butler 2010; Fabre et al. 2005; Jeffries et al. 2007; Lee et al. 2010), P. sorbitophila has its mating-type loci fused with no MATalpha2.
My point is that if there was nothing wrong with the niche then there must have been something wrong with the intermediates--for example they comprised a highly unstable small population that never managed to thrive or do anything other than hang on for dear life while mating (fusing cells) to survive, and incidentally accumulating traits.
Alternatively, similar to the majority of the homothallic fungi in the ascomycetes, F. depauperata might contain both mating alleles which are fused or are linked in one locus.
Pairs of spores were placed on the surface of an agar plate so that they touched, incubated at 30 °C for 4h, and then observed every 10min until either they fused together to form zygotes or budded without mating.
Heterothallic mating in C. neoformans is characterized by the presence of dikaryotic filaments and fused clamp connections, while in self or homothallic mating (monokaryotic fruiting) the septated hyphal segments are monokaryotic and have unfused clamp connections [6], [9].
In brief, feminized fog-2 (q71) mutant worms lacking sperm were mated with males expressing a given centriolar protein fused to GFP, and the resulting embryos were analyzed using immunofluorescence with antibodies against GFP and the pan-centriolar marker IFA.
