Reproductive systems in the myxomycetes: a review

A review of reproduction in the myxomycetes reveals that they have a basic one-locus multiplealleleic heterothallic mating system, which controls syngamy between haploid amoeboflagellates to produce the diploid plasmodium. However, each morphologically defined species contains a number of biological sibling species that can’t interbreed with each other and are centered in different regions of the world. Also, these morphospecies generally contain numerous nonheterothallic strains that can complete the life cycle from a single isolated spore. While there is information that suggests that some of these strains are homothallic, the majority of the evidence supports an apomictic system derived from a blockage of meiosis during spore formation. Thus, these non-heterothallic strains produce diploid amoeboflagellates that can develop directly into plasmodia without the need for crossing.