Format

Send to

Choose Destination
Mol Biol Evol. 2003 Oct;20(10):1730-5. Epub 2003 Jul 28.

Nucleus-encoded, plastid-targeted glyceraldehyde-3-phosphate dehydrogenase (GAPDH) indicates a single origin for chromalveolate plastids.

Author information

1
Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.

Abstract

Plastids (the photosynthetic organelles of plants and algae) originated through endosymbiosis between a cyanobacterium and a eukaryote and subsequently spread to other eukaryotes by secondary endosymbioses between two eukaryotes. Mounting evidence favors a single origin for plastids of apicomplexans, cryptophytes, dinoflagellates, haptophytes, and heterokonts (together with their nonphotosynthetic relatives, termed chromalveolates), but so far, no single molecular marker has been described that supports this common origin. One piece of evidence comes from plastid-targeted glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which originated by a gene duplication of the cytosolic form. However, no plastid GAPDH has been characterized from haptophytes, leaving an important piece of the puzzle missing. We have sequenced genes encoding cytosolic, mitochondrion-targeted, and plastid-targeted GAPDH proteins from a number of haptophytes and heterokonts and found haptophyte homologs that branch within a strongly supported clade of chromalveolate plastid-targeted genes, being more closely related to an apicomplexan homolog than was expected. The evolution of plastid-targeted GAPDH supports red algal ancestry of apicomplexan plastids and raises a number of questions about the importance of plastid loss and the possibility of cryptic plastids in nonphotosynthetic lineages such as ciliates.

PMID:
12885964
DOI:
10.1093/molbev/msg195
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center