Phylogenies of Developmentally Important Proteins Do Not Support the Hypothesis of Two Rounds of Genome Duplication Early in Vertebrate History |
| |
Authors: | Austin L Hughes |
| |
Institution: | (1) Department of Biology and Institute of Molecular Evolutionary Genetics, The Pennsylvania State University, University Park, PA 16802, USA, US |
| |
Abstract: | It has been proposed that two rounds of duplication of the entire genome (polyploidization) occurred early in vertebrate
history (the 2R hypothesis); and the observation that certain gene families important in regulating development have four
members in vertebrates, as opposed to one in Drosophila, has been adduced as evidence in support of this hypothesis. However, such a pattern of relationship can be taken as support
of the 2R hypothesis only if (1) the four vertebrate genes can be shown to have diverged after the origin of vertebrates,
and (2) the phylogeny of the four vertebrate genes (A–D) exhibits a topology of the form (AB) (CD), rather than (A) (BCD).
In order to test the 2R hypothesis, I constructed phylogenies for nine protein families important in development. Only one
showed a topology of the form (AB) (CD), and that received weak statistical support. In contrast, four phylogenies showed
topologies of the form (A) (BCD) with statistically significant support. Furthermore, in two cases there was significant support
for duplication of the vertebrate genes prior to the divergence of deuterostomes and protostomes: in one case there was significant
support for duplication of the vertebrate genes at least prior to the divergence of vertebrates and urochordates, and in one
case there was weak support for duplication of the vertebrate genes prior to the divergence of deuterostomes and protostomes.
Taken together with other recently published phylogenies of developmentally important genes, these results provide strong
evidence against the 2R hypothesis.
Received: 22 December 1997 / Accepted: 5 October 1998 |
| |
Keywords: | : Gene duplication — Genome duplication — Vertebrates — Evolution of development — Protein phylogeny |
本文献已被 PubMed SpringerLink 等数据库收录! |
|