Rate Variation as a Function of Gene Origin in Plastid-Derived Genes of Peridinin-Containing Dinoflagellates |
| |
Authors: | Tsvetan R Bachvaroff M Virginia Sanchez-Puerta Charles F Delwiche |
| |
Institution: | (1) Department of Cell Biology and Molecular Genetics, University of Maryland College Park, H. J. Patterson Hall, College Park, MD 20742, USA;(2) Present address: Center of Marine Biotechnology, 701 East Pratt Street, Baltimore, MD 21202, USA |
| |
Abstract: | Peridinin-pigmented dinoflagellates contain secondary plastids that seem to have undergone more nearly complete plastid genome
reduction than other eukaryotes. Many typically plastid-encoded genes appear to have been transferred to the nucleus, with
a few remaining genes found on minicircles. To understand better the evolution of the dinoflagellate plastid, four categories
of plastid-associated genes in dinoflagellates were defined based on their history of transfer and evaluated for rate of sequence
evolution, including minicircle genes (presumably plastid-encoded), genes probably transferred from the plastid to the nucleus
(plastid-transferred), and genes that were likely acquired directly from the nucleus of the previous plastid host (nuclear-transferred).
The fourth category, lateral-transferred genes, are plastid-associated genes that do not appear to have a cyanobacterial origin.
The evolutionary rates of these gene categories were compared using relative rate tests and likelihood ratio tests. For comparison
with other secondary plastid-containing organisms, rates were calculated for the homologous sequences from the haptophyte
Emiliania huxleyi. The evolutionary rate of minicircle and plastid-transferred genes in the dinoflagellate was strikingly higher than that
of nuclear-transferred and lateral-transferred genes and, also, substantially higher than that of all plastid-associated genes
in the haptophyte. Plastid-transferred genes in the dinoflagellate had an accelerated rate of evolution that was variable
but, in most cases, not as extreme as the minicircle genes. Furthermore, the nuclear-transferred and lateral-transferred genes
showed rates of evolution that are similar to those of other taxa. Thus, nucleus-to-nucleus transferred genes have a more
typical rate of sequence evolution, while those whose history was wholly or partially within the dinoflagellate plastid genome
have a markedly accelerated rate of evolution.
Electronic Supplementary Material Electronic Supplementary material is available for this article at
and accessible for authorised users.
Reviewing Editor: Dr. Debashish Battacharya] |
| |
Keywords: | Dinoflagellate Endosymbiosis Plastid Relative rate test Gene transfer |
本文献已被 PubMed SpringerLink 等数据库收录! |
|