title: Conserved regions in mammalian beta-globins: could they arise by cross-species gene exchange?
abstract: Comparison of the nucleotide sequences from the coding regions of the four mammalian beta-globin genes shows that different parts of these genes have evolved at two different rates. Those codons designating amino acids 1-20, 41-91 and 109-146 have accumulated substitutions in a random fashion as the molecular clock hypothesis would predict. The codons at positions 21-40 and 91 to 108 behave as if they evolved at a much slower rate. Each of the slowly evolved regions contains an intron. Conservation of the coding sequences flanking the introns are hypothesized to be the result of corss-species gene exchange.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003062:Codon / Q000235:genetics; D005796:Genes; D014644:Genetic Variation; D005914:Globins / Q000235:genetics*; D006041:Goats; D006801:Humans; D008322:Mammals / Q000235:genetics*; D051379:Mice; D008957:Models, Genetic; D011817:Rabbits
chemical_list: D003062:Codon; D005914:Globins