Molecular evolution of a portion of the mitochondrial 16S ribosomal gene region in scleractinian corals |
| |
Authors: | Sandra L Romano Stephen R Palumbi |
| |
Institution: | (1) Department of Zoology and Kewalo Marine Lab, University of Hawaii, Honolulu, HI 96822, USA, US |
| |
Abstract: | Relationships among families and suborders of scleractinian corals are poorly understood because of difficulties 1) in making
inferences about the evolution of the morphological characters used in coral taxonomy and 2) in interpreting their 240-million-year
fossil record. Here we describe patterns of molecular evolution in a segment of the mitochondrial (mt) 16S ribosomal gene from taxa of 14 families of corals and the use of this gene segment in a phylogenetic analysis of relationships
within the order. We show that sequences obtained from scleractinians are homologous to other metazoan 16S ribosomal sequences
and fall into two distinct clades defined by size of the amplified gene product. Comparisons of sequences from the two clades
demonstrate that both sets of sequences are evolving under similar evolutionary constraints: they do not differ in nucleotide
composition, numbers of transition and transversion substitutions, spatial patterns of substitutions, or in rates of divergence.
The characteristics and patterns observed in these sequences as well as the secondary structures, are similar to those observed
in mt 16S ribosomal DNA sequences from other taxa. Phylogenetic analysis of these sequences shows that they are useful for evaluating
relationships within the order. The hypothesis generated from this analysis differs from traditional hypotheses for evolutionary
relationships among the Scleractinia and suggests that a reevaluation of evolutionary affinities in the order is needed.
Received: 4 September 1996 / Accepted: 7 April 1997 |
| |
Keywords: | : Scleractinia — Mitochondrial 16S ribosomal RNA — Secondary structure models — Phylogenetic analysis |
本文献已被 SpringerLink 等数据库收录! |
|