The Structure and Evolution of the Human /?-Globin Gene Family

Abstract

Argiris Efstratiadis Department of Biological Chemistry Harvard Medical School Boston, Massachusetts 02115 James W. Posakony, Tom Maniatis, Richard M. Lawn* and Catherine O’Connell+ Division of Biology California Institute of Technology Pasadena, California 91125 Richard A. Spritz, Jon K. DeRiel,# Bernard G. Forget and Sherman M. Weissman Departments of Genetics and Internal Medicine Yale University School of Medicine New Haven, Connecticut 06510 Jerry L. Slightom, Ann E. Blechl and Oliver Smithies Laboratory of Genetics University of Wisconsin Madison, Wisconsin 53706 Francisco E. Baralle, Carol C. Shoulders and Nicholas J. ProudfootQ MRC Laboratory of Molecular Biology Hills Road Cambridge CB2 2QH, England Summary We present the results of a detailed comparison of the primary structure of human p-like globin genes and their flanking sequences. Among the se- quences located 5’ to these genes are two highly conserved regions which include the sequences ATA and CCAAT located 31 2 1 and 77 + 10 bp, respectively, 5’ to the mRNA capping site. Similar sequences are found in the corresponding locations in most other eucaryotic structural genes. Calcula- tion of the divergence times of individual @like globin gene pairs provides the first description of the evolutionary relationships within a gene family based entirely on direct nucleotide sequence com- parisons. In addition, the evolutionary relationship of the embryonic e-globin gene to the other human P-like globin genes is defined for the first time. Finally, we describe a model for the involvement of short direct repeat sequences in the generation of deletions in the noncoding and coding regions of B-like globin genes during evolution.