Studies on Mitoplastide Genome and Origin of Mitochondria and Chloroplast in Plants

Abstract

All extant photosynthetic organisms descend from a primeval photosynthetic operon of the single evolutionary line of cells. This hypothesis proposed existence of mitoplastide genome in the aerobic oxygen non-producing proto-eukaryot. This genome is composed of whole mitochondrial replicon and photosynthetic gene cluster surrounded by membrane. Development of water spliting-PSII superoperon in plants, is a results of mitoplastide genome duplication and gene's function replacement. After both events, mitoplastide genome contain two functionaly polarized replicons (mitochondrial and plastid's). The major driving forces in gene modeling and functional replacements in photosynthetic genes replicon are diameter of the Earth and brightness of the Sun at the time when life originated.  The origin of mitochondrion and chloroplast occured in three steps. First, a replication fork pauses and collapsed, generating a break in the mitoplastide genome. Second, the double-strand break was repaired by complementary strands invasion. Third, this duplicated genome was segregated into two compartments by reciprocal genetic recombination. Simultaneous, with genetic recombination, fission of the mitoplastide membrane formed two compartments, mitochondrial and plastid’s.