Mitochondrial Evolution: Should I stay or should I go?
Jonathan Choy, Kenneth Liu, Catherine Tucker, Mitra Esfandirei, Steven Quayle
Molecular Biology and Evolution (2001)
Category: FAKES ¤ Added: Jan 21, 2007 ¤ Rating: ◊◊
The distinction between prokaryotic and eukaryotic cell structure is still accepted today as the most fundamental discontinuity in the living world. In the process of analyzing the newly sequenced bacterium Rickettsia prowazekii it was discovered through a BLAST search that a non-coding region of DNA showed high homology to the importin-á gene of eukaryotes. The genomes of Rickettsia canada and Rickettsia rickettsii were both found to contain a sequence homologous to importin-á as well. This sequence was found to have high homology when compared to the primitive protists Nosema locustae and Reclinomonas americana, which close ancestors to the lineage. The predicted protein sequence of R. prowazekii, R. canada and R. rickettsii contained the highly conserved amino acid motif cys-arg-glu-ala-thr-glu-…-ser-glu-val-glu-asn-asp-ala-tyr-ser. We believe this motif may be specific to a new lineage of prokaryotes, which we have termed the Eukobacteria. Through the data collected we propose a new model of mitochondrial evolution wherein one or more mitochondria escaped from their eukaryotic hosts and developed into the Eukobacteria.