Evidence against the exon theory of genes derived from the triose-phosphate isomerase gene.

AUTOR(ES)

Kwiatowski, J

RESUMO

The exon theory of genes proposes that the introns of protein-encoding nuclear genes are remnants of the DNA spacers between ancient minigenes. The discovery of an intron at a predicted position in the triose-phosphate isomerase (EC 5.3.1.1) gene of Culex mosquitoes has been hailed as an evidential pillar of the theory. We have found that that intron is also present in Aedes mosquitoes, which are closely related to Culex, but not in the phylogenetically more distant Anopheles, nor in the fly Calliphora vicina, nor in the moth Spodoptera littoralis. The presence of this intron in Culex and Aedes is parsimoniously explained as the result of an insertion in a recent common ancestor of these two species rather than as the remnant of an ancient intron. The absence of the intron in 19 species of very diverse organisms requires at least 10 independent evolutionary losses in order to be consistent with the exon theory.

Documentos Relacionados

• Seven newly discovered intron positions in the triose-phosphate isomerase gene: evidence for the introns-late theory.
• Erythrocyte lipids in triose-phosphate isomerase deficiency.
• The tigA gene is a transcriptional fusion of glycolytic genes encoding triose-phosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase in oomycota.
• Cloning and sequencing of a cDNA clone encoding the cytosolic triose-phosphate isomerase from Arabidopsis thaliana.
• cDNA cloning and functional expression of the Schistosoma mansoni protective antigen triose-phosphate isomerase.