English

Milanko Stupar

doi:10.5897/bmbr11.026

Abstract

Division of the ancestral prokaryotic genome into two circular double-stranded deoxyribonucleic acid (DNA) molecules by genetic recombination, is a basis for the future separate evolution of the nuclear and mitochondrial gene compartment. This suggests monophyletic origin of both mitochondrion and nucleus. Presumed organism which genome undergoes genetic recombination has to be searched among an aerobic, oxygen non-producing archaeon with no rigid cell wall, but a plasma membrane, probably an crenarchaeota containing functional bacteriochlorophyll a synthase gene and histones. In this proposal, origin of eukaryotes occur by a three-steps. First, replication fork pauses and collapses generating a breakage in the genome of archaeal ancestor of eukaryotes. Second, the double-strand break can be repaired intergenomically by complementary strands invasion. Third, this duplicated genome can be fissioned into two compartments by reciprocal genetic recombination. Scenario is accomplished by aberrant fission of the inner membane surrounding separately those two compartments. Key words: Origin of nucleus, origin of mitochondrion.

Highlights

Archaebacterial ancestor of eukaryotesOrganisms are clasiffied into three Domains and into one of six Kingdoms of life
There is opinion that Archaebacteria (Archaea) have an ancestor in common with eukaryots, which has been shown by a phylogenic analysis based upon nucleotide and amino-acid sequences comparison showing deep archaeal root of eukaryots (Woese et al, 1990)
Archaeal-derived genes are significantly more likely to be essential to eukaryotic viability, are more highly expressed, and are significantly more highly connected and more central in the eukaryotic protein interaction network than that of eubacterial origin (Cotton and Mcinerney, 2010.)