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Amoeba
are notoriously celibate. This is one of the first things that we
learn about amoeba at school. However, there are indications that
amoeba do in fact take part in sexual or at least parasexual activities.
Parasex seems to occur sporadically through many unconnected genera of
amoeba. This may reflect sex being "invented" (or lost)
at various times throughout amoeboid lineages. Perhaps a testament to
the utility of sex? Acrasis. Now
strongly suspected of being a member of the Heterolobosea , Acrasis
produces spores like slime moulds in a parasexual process.
Heteramoeba
clara. I confess that I do not understand the crossing
experiments undertaken by Droop (Droop,
1962) to determine evidence for a sexual cycle
in this amoeba.
Sapinia
diploidia Suggested of carrying out nuclear exchange in the
binuclear cyst (Goodfellow
et al, 1974).
Flabellula
baltica. Cell fusion has been observed between individuals in
population of the marine amoeba Flabellula baltica (Smirnov,
1999). There may of course be a number of explanations for this
behaviour, this could for example be a method by which benificial
symbioitc bacteria are passed around but a more obvious interpretation
is that this is a sexual process. If this process is more
widespread amongst other amoebal species then this would have worrying repercussions
on the validity of mitochondrial DNA lineage analysis and the great new
hope that SSUrDNA anaysis promises!! This would if it happened
even at low levels then horizontal transmission of these genes may occur
frequently, especially in the percolozoa amoeba and the entamoebida which
have there ribosomal DNA genes on multicopy plasmids!,
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