Nozaki H
Origin
and evolution of the genera Pleodorina and Volvox (Volvocales)
BIOLOGIA 58 (4): 425-431 JUL 2003
Abstract: The previous molecular phylogenetic study using 6021 base pairs from five
chloroplast genes suggested that two species of Pleodorina
(P. californica, P. japonica) might have evolved from
a Volvox-like alga by the decrease in colony cell
number and size. However, number of species of the genus Volvox
was very limited especially in the section Merrillosphaera.
In the present study,
6021 base pairs of the concatenated five chloroplast genes from 10 strains
representing seven taxa of the genus Volvox were added to the previous data matrix. The sequence
data resolved two anisogamous/oogamous clades within a large monophyletic group comprising five
advanced genera of the Volvocaceae (Yamagishiella, Platydorina,
Eudorina, Pleodorina and Volvox), one containing Volvox
sect. Volvox and the anisogamous
genus Platydorina (32-celled flattened
colony), and the other (Eudorina group) composed of
three other sections of Volvox, Pleodorina
and Eudorina. The isogamous
genus Yamagishiella (32-celled colony) was positioned
basally to the Eudorina group. Therefore, evolution
of anisogamy with sperm packets from isogamy might have occurred twice within the Volvocaceae. Based on the present molecular phylogenetic analysis, species of Volvox
and Pleodorina within the Eudorina
group represented three and two, respectively, separate lineages. One the three Volvox lineages [composed
of V (sect. Merrillosphaera) carteri, V (sect. Merrillosphaera)
obversus, V. (sect. Merrillosphaera) tertius, V. (sect. Merrillosphaera) africanus and V (sect. Copelandosphaera)
dissipatrix] was sister to the monophyletic group
consisting of one of the two Pleodorina lineages (P. californica and P. japonica) and V (sect. Janetosphaera) aureus. In addition, species of Eudorina
were basal to the two lineages of Pleodorina and
three Volvox lineages within the Eudorina
group, representing the ancestral situation of Pleodorina/Volvox
(excluding sect. Volvox). Thus, reverse evolution from a Volvox-like
alga to Pleodorina suggested previously appears
unlikely.
Nozaki H, Misawa K, Kajita T, et
al.
Origin
and evolution of the colonial Volvocales (Chlorophyceae) as inferred from multiple, chloroplast gene
sequences
MOLECULAR PHYLOGENETICS AND EVOLUTION 17 (2): 256-268 NOV 2000
Abstract: A combined data set of DNA sequences (6021 bp) from five protein-coding genes of the chloroplast
genome (rbcL, atpB, psaA, psaB, and psbC genes) were analyzed for 42 strains representing 30
species of the colonial Volvocales (Volvox and its relatives) and 5 related species of green
algae to deduce robust phylogenetic relationships
within the colonial green flagellates. The 4-celled family Tetrabaenaceae
was robustly resolved as the most basal group within the colonial Volvocales. The sequence data also suggested that all five volvocacean genera with 32 or more cells in a vegetative
colony (all four of the anisogamous/oogamous genera, Eudorina, Platydorina, Pleodorina, and Volvox, plus the isogamous genus Yamagishiella)
constituted a large monophyletic group, in which 2 Pleodorina
species were positioned distally to 3 species of Volvox.
Therefore, most of the evolution of the colonial Volvocales
appears to constitute a gradual progression in colonial complexity and in types
of sexual reproduction, as in the traditional volvocine
lineage hypothesis, although reverse evolution must be considered for the
origin of certain species of Pleodorina. Data
presented here also provide robust support for a monophyletic family Goniaceae consisting of two genera: Gonium and Astrephomene.
Coleman AW
Phylogenetic analysis of "Volvocacae"
for comparative genetic studies
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
96 (24): 13892-13897
Abstract: Sequence analysis based on multiple
isolates representing essentially all genera and species of the classic family Volvocaeae has clarified their phylogenetic
relationships. Cloned internal transcribed spacer sequences (ITS-1. and ITS-2,
flanking the 5.8S gene of the nuclear ribosomal gene cistrons)
were aligned, guided by ITS transcript secondary structural features, and
subjected to parsimony and neighbor joining distance analysis. Results confirm
the notion of a single common ancestor, and Chlamydomonas
reinharditii alone among all sequenced green unicells is most similar. interbreeding
isolates were nearest neighbors on the evolutionary tree in all cases. Some taxa, at whatever level, prove to be clades
by sequence comparisons, but others provide striking exceptions. The
morphological species Pandorina morum,
known to be widespread and diverse in mating pairs, was found to encompass all
of the isolates of the four species of Volvulina. Platydorina appears to have originated early and not
to fall within the genus Eudorina, with which it can
sometimes be confused by morphology. The four species of Pleodorina
appear variously associated with Eudorina examples.
Although the species of Volvox are each clades, the genus Volvox is not The conclusions confirm and extend prior, more limited,
studies on nuclear SSU and LSU rDNA genes and
plastid-encoded rbcL and atpB.
The phylogenetic tree suggests which classical
taxonomic characters are most misleading and provides a framework for molecular
studies of the cell cycle-related and other alterations that have engendered
diversity in both vegetative and sexual colony patterns in this classical
family.
Nozaki H, Ito M, Sano R, et al.
Phylogenetic analysis of Yamagishiella
and Platydorina (Volvocaceae,
Chlorophyta) based on rbcL
gene sequences
JOURNAL OF PHYCOLOGY 33 (2): 272-278 APR 1997
Abstract: Yamagishiella,
based on Pandorina unicocca
Rayburn et Starr is distinguished from Eudorina by its isogamous sexual
reproduction, whereas Platydorina exhibits anisogamous sexual reproduction. In the present study, rue
sequenced the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase
(rbcL) genes from five Japanese and North American
strains of Y. unicocca (Rayburn et Stair) Nozaki,
true Platydorina caudata
Kofoid strains, and two strains of Eudorina unicocca G. M. Smith, as
well as eight related colonial and unicellular species. Phylogenetic
trees were constructed based on these sequence data and on previously published
rbcL gene sequences from 23 volvocalean
species in order to deduce phylogenetic relationships
within the colonial Volvocales, with particular
regard to the phylogenetic positions and status of
the genera Yamagishiella and Platydorina.
Two robust monophyletic groups of the anisogamous/oogamous
volvocacean species were resolved in the
maximum-parsimony tree as well as in the neighbor-joining distance tree. One of
the two groups comprises three species of Volvox
section Volvox, whereas the other is composed of
other sections of Volvox as well as of all the
species of Eudorina and Pleodorina.
Platydorina, however, was positioned outside
these two monophyletic groups. Therefore, derivation of the Platydorina
lineage may be earlier than that of such anisogamous/oogamous
groups, or origin of ''anisogamy with sperm,
packets'' in Platydorina may De independent of
sperm packet evolution in Eudorina, Pleodorina, and Volvox. It was
also resolved with high bootstrap values that all of the Y. unicocca
strains form a monophyletic group positioned outside the large monophyletic
group including Eudorina and Pleodorina.
These reject the possibility of the reverse evolution of isogamy
from anisogamy to give rise to Yamagishiella
within the lineage of Eudorina.
Title: DEVELOPMENT OF THE FLAGELLAR
APPARATUS AND FLAGELLAR POSITION IN THE COLONIAL GREEN-ALGA PLATYDORINA-CAUDATA
(CHLOROPHYCEAE)
Author(s): TAYLOR MG,
FLOYD GL,
HOOPS HJ
Source: JOURNAL OF PHYCOLOGY 21 (4): 533-546
DEC 1985
CRAYTON MA
PRESENCE
OF A SULFATED POLYSACCHARIDE IN THE EXTRACELLULAR-MATRIX OF PLATYDORINA-CAUDATA
(VOLVOCALES, CHLOROPHYTA)
JOURNAL OF PHYCOLOGY 16 (1): 80-87 1980
HARRIS DO
LIFE-HISTORY
AND GROWTH INHIBITION STUDIES IN PLATYDORINA-CAUDATA (VOLVOCACEAE)
BULLETIN DE LA SOCIETE BOTANIQUE DE
HARRIS DO
AN
AUTOINHIBITORY SUBSTANCE PRODUCED BY PLATYDORINA-CAUDATA KOFOID
PLANT PHYSIOLOGY 45 (2): 210& 1970
HARRIS DO
NUTRITION
OF PLATYDORINA CAUDATA KOFOID
JOURNAL OF PHYCOLOGY 5 (3): 205& 1969
HARRIS DO
AN
AUTO-INHIBITORY SUBSTANCE PRODUCED BY PLATYDORINA CAUDATA
JOURNAL OF PHYCOLOGY S 3: 9& Suppl. S 1967