Relation of an evolutionary mechanism to differentiation.
It is believed that new gene products and differentiations arise during evolution by the creation of new members of families of repeated DNA sequences which undergo diversification and take on new functions, while still retaining some common sequences indicating their common ancestry. Since some of the sequences of such DNA families control differentiations that occur in present-day embryos, it appears that members of such families formed during evolution are active in development. The presence of partially homologous proteins in related types of cells, as well as the labile pattern of determination and differentiation of these cells, supports this idea. The ontogenetic sequence of differentiation follows the phylogenetic one and this may occur because the more conservative members of any family of DNA sequences are more reiterated and transcribe more copies of RNA.
D000818:Animals; D005075:Biological Evolution; D002454:Cell Differentiation; D004247:DNA / Q000032:analysis; D004627:Embryonic Induction; D005815:Genetic Code; D005855:Germ Layers / Q000032:analysis; D006801:Humans; D010802:Phylogeny; D011506:Proteins / Q000032:analysis; D012313:RNA / Q000032:analysis; D051381:Rats; D013045:Species Specificity
D011506:Proteins; D012313:RNA; D004247:DNA