RESUMEN
The genes encoding carbonic anhydrase I (CA I) have been characterized for chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla). In addition, 44 nucleotides (nt) at the 5' end of the noncoding first exon (exon 1a), which is unique to the erythroid CA I mRNA, together with 188 nt of the adjacent 5' flanking regions, were sequenced for the corresponding positions of the CA I of orangutan, pigtail macaque, and squirrel monkey. When these 5' flanking regions are compared, along with those published for human and mouse CA I, they were found to contain several conserved sequences that may bind factors involved in the erythroid-specific expression of CA I. Comparisons of the human, chimpanzee, and gorilla coding and noncoding CA I sequences do not significantly deviate from a pattern of trichotomy for the evolutionary origins of these three hominoid species.