Статеечка за происхождение жизни..

[origen_72]

"The Last Universal Common Ancestor (LUCA) of all life forms on Earth (Doolittle, 2000;

Theobald, 2010) is far more complex than RNA-world organisms described above. Its heredity is

based on DNA rather than RNA, and it has fully developed protein synthesis programmed by

genes. The integrity of the DNA is maintained by a group of “maintenance” enzymes, including

DNA topoisomerase, DNA ligase and other DNA repair enzymes. The RNA-polymerase

complex is used to synthesize mRNA copies of each gene, and then each mRNA is translated

into a protein by the action of ribosomes and tRNA. LUCA can make fatty acids from sugars and

therefore it is no longer dependent on the supply of abiotically synthesized hydrocarbons. The

outer membrane of LUCA includes ion pumps. Although the genome of LUCA is a product of

phylogenetic reconstruction, it is possible that bacterial spores that arrived to the primordial

Earth from cosmic sources had functional complexity similar to LUCA. Based on the rate of

complexity increase (Fig. 1), we expect that RNA-world cells emerged ca. 2 billion years after

the origin of life, and LUCA-like organisms appeared ca. 3 billion years later."