Reproductive systems of myxomycetes: How does evolution shape the relative proportion of sexual and asexual reproduction in species that are able to do both?
Final Report Abstract
The main conclusions that can be drawn from this project are the following: 1. Sexual reproduction seems to be an important, if not the dominating mode (apart from clonal myxamoebal populations built up by binary fission) of reproduction in naturally occurring populations of myxomycetes. Clonal populations of amoebae seem to occur regularly and may persist over long periods of time, but plasmodia (giving later rise to fruit bodies) seem usually to originate from sexual events. At the present state of knowledge, we cannot rule out the occurrence of deviations (especially automixis or apomixis), but if occurring, they must be rare. 2. From the two investigated species complexes we can expect many, if not most, morphospecies to be composed of reproductively isolated, sexually reproducing, biospecies. These putative biospecies cannot (Trichia varia), in part (Meriderma atrosporum agg.), or mostly (Tubifera ferruginosa-complex) be distinguished by morphological characters. Therefore, molecular markers will be the key to apply the biospecies concept successfully in myxomycetes. 3. Partial SSU sequences, as most widely used in this study, seem to represent suitable barcode markers for the group and can be used to distinguish the (usually cryptic) biospecies, although they alone do not allow any conclusions about reproductive isolation and speciation processes. As such, surveys focusing on diversity or ecology of myxomycetes should be accompanied by a molecular component to visualize not only the morphospecies, but as well the true evolutionary units (putative biospecies). 4. We have to expect a significant amount of hidden diversity in myxomycetes, which will increase the number of taxa from ca. 1000 recognized morphologically by a factor between two and ten. Although myxomycetes are an evolutionary old group of simple eukaryotes, they are still in rapid evolution, and we can expect that the often large or even cosmopolitan ranges of the morphospecies will dissolve into more narrow ranges if biospecies are considered in biogeographic studies.
Publications
- (2011): Genetic structure of two protist species (Myxogastria, Amoebozoa) reveals possible predominant asexual reproduction in sexual amoebae. PLoS ONE 6: e22872
Fiore-Donno AM, Novozhilov YK, Meyer M, Schnittler M
(See online at https://doi.org/10.1371/journal.pone.0022872) - (2015) Sex or no sex? Independent marker genes and group I introns reveal the existence of three sexual but reproductively isolated biospecies in Trichia varia (Myxomycetes). Org Div Evol 15: 631–650
Feng, Y, Schnittler, M.
(See online at https://doi.org/10.1007/s13127-015-0230-x) - (2016) What an intron may tell: several sexual biospecies coexist in Meriderma spp. (Myxomycetes). Protist, Volume 167, Issue 3, June 2016, Pages 234-253
Feng Y, Klahr A, Janik P, Ronikier A, Hoppe T, Novozhilov YK, Schnittler M
(See online at https://doi.org/10.1016/j.protis.2016.03.003) - Molecular or morphological species? Myxomycete diversity in a deciduous forest in northeastern Germany. Nova Hedwigia, Volume 104, Numbers 1-3, February 2017, pp. 359-380(22)
Feng, Y, Schnittler, M.
(See online at https://doi.org/10.1127/nova_hedwigia/2016/0326)
