In the rabbit, two beta-like globin genes, beta 3 and beta 4, are expressed in embryonic erythrocytes and one, beta 1, is expressed in fetal and adult erythrocytes. The complete nucleotide sequence of embryonic gene beta 4 is presented, including the region from 582 base pairs before the cap site to 508 base pairs after the poly(A) addition site. beta 4 has the tripartite structure characteristic of animal globin genes, being interrupted by intervening sequences within codon 30 and between

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... s 104 and 105. Conserved sequences thought to play roles in transcription, RNA processing, and translation are found in beta 4. Rabbit gene beta 4 shows substantial homology to the human embryonic epsilon-globin gene, not only in message-coding blocks, but also in the 5' and 3' flanking regions and in the two intervening sequences. Comparison of all four rabbit beta-like genes with those of humans suggests that a primordial four gene family, 5'-epsilon-gamma-delta-beta-3', existed prior to the mammalian radiation. An alignment of the 5' flanking sequences of a collection of animal beta-like globin genes shows some conserved regions that differ between the adult genes and the embryonic/fetal genes. These could reflect a common evolutionary lineage rather than stage-specific control sequences.