THE BETA-GLOBIN GENE-CLUSTER OF THE PROSIMIAN PRIMATE GALAGO-CRASSICAUDATUS - NUCLEOTIDE-SEQUENCE DETERMINATION OF THE 41-KB CLUSTER AND COMPARATIVE SEQUENCE ANALYSES

The nucleotide sequence of the β globin gene cluster of the prosimian Galago crassicaudatus has been determined. A total sequence spanning 41, 101 bp contains and links together previously published sequences of the five galago β-like globin genes (5′-ε{lunate}-γ-ψη-δ-β-3′). A computer-aided search for middle interspersed repetitive sequences identified 10 LINE (L1) elements, including a 5′ truncated repeat that is orthologous to the full-length L1 element found in the human ε{lunate}-γ intergenic region. SINE elements that were identified included one Alu type I repeat, four Alu type II repeats, and two methionine tRNA-derived Monomer (type III) elements. Alu type II and Monomer sequences are unique to the galago genome. Structural analyses of the cluster sequence reveals that it is relatively A + T rich (about 62%) and regions with high G + C content are associated primarily with globin coding regions. Comparative analyses with the β globin cluster sequences of human, rabbit, and mouse reveal extensive sequence homologies in their genic regions, but only human, galago, and rabbit sequences share extensive intergenic sequence homologies. Divergence analyses of aligned intergenic and flanking sequences from orthologous human, galago, and rabbit sequences show a gradation in the rate of nucleotide sequence evolution along the cluster where sequences 5′ of the ε{lunate} globin gene region show the least sequence divergence and sequences just 5′ of the β globin gene region show the greatest sequence divergence. © 1992.