FETAL RECRUITMENT OF ANTHROPOID GAMMA-GLOBIN GENES - FINDINGS FROM PHYLOGENETIC ANALYSES INVOLVING THE 5'-FLANKING SEQUENCES OF THE PSI-GAMMA-1 GLOBIN GENE OF SPIDER MONKEY ATELES-GEOFFROYI

We determined the nucleotide sequence of a 2.5 kb DNA fragment (1 kb is 103 base-pairs) that includes exon 1, intron 1 and about 1.4 kb of 5′-flanking DNA of the spider monkey γ1-globin pseudogene locus and compared this sequence to its homologues from other primates and rabbit. This region of the γ1 locus of spider monkey still retains conserved regulatory elements, suggesting that it became a pseudogene late in New World monkey phylogeny. In the 250 base-pair region immediately 5′ from the transcription start site where many known regulatory elements are located, a higher rate of nucleotide substitutions occurred in the ancestral anthropoid (human, ape and monkey) lineage than in the prosimian (galago) lineage, as was also the case for non-synonymous substitutions in the coding region. The opposite pattern was observed for most other non-coding regions and for synonymous substitutions. These substitution patterns correlate with the embryonic-to-fetal transformation of the γ-globin genes of the ancestral anthropoids. Analysis of the 5′-flanking sequences suggests that 11 gene conversion events have occurred in the anthropoid γ-gene lineages. In the parts of the 5′-flanking region where no gene conversions have been detected, γ2-gene sequences have accumulated more nucleotide changes than γ1, which suggests that the γ2 gene was the more redundant duplicate that may have accumulated first the nucleotide changes responsible for the anthropoid fetal pattern of γ-globin gene expression. © 1992.