Ma. Buchheim et al., PHYLOGENY OF THE VLE-14 CHLAMYDOMONAS (CHLOROPHYCEAE) GROUP - A STUDYOF 18S RIBOSOMAL-RNA GENE-SEQUENCES, Journal of phycology, 33(6), 1997, pp. 1024-1030
Comparative specificity of sporangial wall autolysins (i.e. vegetative
lytic enzymes [VLE]) derived from sporulating cultures has been wed t
o group Chlamydomonas taxa into 15 different VLE types. The VLE-14 gro
up including isolates of C. geitleri, C. noctigama, C. monoica, C. pin
icola, C. terricola, and C. hindakii, is one of the largest of these V
LE groups. Genetic studies have shown that a number of the VLE-14 taxa
are interfertile, albeit with little or reduced viability of progeny.
A reevaluation of the VLE-14 group suggested that all members should
be regarded as distinct isolates of C. noctigama. The present investig
ation tests the phylogenetic implications of the VLE evidence and exam
ines the validity of the taxonomic reevaluation in a phylogenetic cont
ext by analysis of 18S rRNA gene sequence data. Results from analyses
of the sequence data are consistent with an interpretation of the VLE
evidence as indicative of monophyletic taxa. Phylogenetic analyses of
the sequence data are also consistent with the taxonomic reevaluation
and reidentification of the group. However, at least some of the VLE-1
4 isolates studied in this investigation fit criteria for distinct bio
logic or phylogenetic species. It is concluded that the VLE-14 taxa re
present a very closely allied group that includes some isolates that a
re in the early stages of speciation by reproductive isolation.