Phylogenetics PG_D0010

Title : http://www.cs.man.ac.uk/~gowrishv/phase-1.1-manual.pdf
Author : Carlos Saavedra and Juan B. Peña
Year : 2006
Place of publish : SpringerLink
Abstract :

Pectinids constitute one of the most conspicuous
groups of marine bivalves, and include some
of the most important species from the point of view of
Wsheries and aquaculture. In spite of this, their systematics
and evolution are not well understood. Only two
molecular phylogenetic analyses based on relatively
wide taxonomic samplings have been published. These
studies largely neglected American species, some of
which are central for testing current models of pectinid
evolution and diversiWcation, or are commercially valuable.
We have sequenced 820 nucleotide base pairs of
the 12S and 16S ribosomal RNA genes in nine species
of pectinids belonging to six genera living along American
coasts. Sequences from homologous regions of 19
other species were gathered from public databases. We
constructed phylogenetic maximum-parsimony and
maximum-likelihood trees of this set of 28 taxa. Our
phylogenetic analysis indicates that Crassadoma is
polyphyletic, and cementation to the substrate as a life
habit could have appeared independently in two geographic
chlamydinid lineages. Nodipecten is placed in
the subfamily Pectininae, and the suspected close relationship
of Amusium, Euvola and Pecten within this
subfamily is also supported. Zygochlamys patagonica
appears in the Chlamydinae subfamily, as expected.
The existence of a separate subfamily Palliolinae is
suggested but not supported statistically. The position
of Argopecten, Aequipecten and Flexopecten within the
subfamily Pectinidae, suggested by a recent study,
could not be conWrmed, and we argue that it could be
due to a combination of long branch attraction and
incomplete sequencing.