REDUCTIVE 2

REDUCTIVE EVOLUTION OF GENOMES

Sarai Araujo Aris, María Ulloa Vallejo

GENES THAT ARE MAINTAINED- Genes involved in core cellular functions: replication, transcription and translation.- Intracellular bacteria: genes that complement hosts' metabolic pathways.- Pathogenic parasites: genes involved in parasite-host interaction.

GENES THAT ARE LOST- Genes of biosynthetic pathways: fatty acids, phospholipids and peptidoglycans- Genes coding for regulation of gene expression and DNA repair pathway proteins.Genome compactation also occurs!

Nucleomorphs:- Diploid genome of 3 chromosomes as the result of the lost of genes.- Short intergenic regions, genes overlaped or co-transcribed and the tiniest introns.Microbial communities:- Black Queen Hypothesis takes place: Essential genes for an organism can be lost if metabolites are provided by other community members.

Evolutionary process is divided in two phases:- Genomic complexification happens in bursts, at an exponential rate in stages of innovation. A brief process, characterized by dramatic genomic and phenotypic changes.- Genomic simplification occurs gradually, at the rate of exponential decay. The succesion of the two phases is the pattern that defines the course of the evolution in time over history.

BIPHASIC MODEL OF EVOLUTION

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