A review of key publications concerning the biology and life cycles of
microsporidians has led us to challenge recent proposals that they ex
hibit a unique process of meiosis when compared with other eukaryotes.
The basic data used to support this challenge are the same as those u
sed by researchers suggesting atypical meiosis, but the data are analy
zed from a different viewpoint. Arguments are put forward to support a
testable hypothesis that meiosis in microsporidians is identical to t
hat which occurs in other eukaryotes. It is proposed that confusion re
sulted because two separate cytological developmental sequences for di
plokaryotic meronts in mosquito fat body cells were previously interpr
eted as a single sequence. By rearrangement of the original data into
two developmental sequences. one abortive and the other for typical me
iosis, a better fit was obtained between cytological stages and microp
hotometric measurements of nuclear DNA content. This improved data fit
and the existence of similar nuclear developmental sequences in the f
ungi are used to support our hypothesis.