Resumen

EGUIARTE, Luis E; CASTILLO, Amanda  y  SOUZA, Valeria. Evolución molecular y genómica en angiospermas. INCI [online]. 2003, vol.28, n.3, pp.141-147. ISSN 0378-1844.

Several aspects of the evolution of the genomes in angiosperms were reviewed, synthesized and compared. Flowering plants have three genomes: chloroplast, mitochondrial and nuclear. The chloroplast genome has a largely conserved structure (120-217kb) including 110-113 genes. The mitochondrial genome is bigger (300-600kb), comprising about 60 genes, and is a very dynamic genome, losing and acquiring genes from the nucleus and chloroplast. Nuclear genomes in angiosperms are among the largest known. In Arabidopsis thaliana it is 125Mb long with 25498 genes. From rice (Oryza sativa) two varieties have been sequenced; its genome is almost 4 times larger than that of A. thaliana and includes 32000-55615 genes. Maize (Zea mays) has not been sequenced yet, but there is substantial genomic information, and it has been estimated that between 60 to 80% is composed of mobile elements. Synonymous substitutions in chloroplast genes are 2 to 3 times faster than in mitochondria, and nuclear genes change in general 10 to 15 times faster than mitochondrial. Nevertheless, substitution rates in non-synonymous sites are similar between chloroplast and mitochondria and only slightly higher in the nuclear genome. Detailed studies of these 3 genomes allow the understanding of the complexities of the genetics and evolution of this group of plants.

Palabras clave : Angiospermas; Arroz; Cloroplasto; Genoma; Maíz; Mitocondria.