title: Linkage of adult alpha- and beta-globin genes in X. laevis and gene duplication by tetraploidization.
abstract: We have used cloned adult X. laevis alpha- and beta-globin cDNAs to analyze globin genes in X. laevis DNA. We detected alpha 1- and beta 1-globin genes which contain intervening sequences and code for the major adult globins, plus additional diverged alpha 2- and beta 2-globin genes of unknown coding potential. Unlike the case in mammals, the X. laevis alpha 1- and beta 1-globin genes are closely linked and occur in the sequence 5'-alpha 1-9 kb-beta 1-3'. The alpha 2- and beta 2-globin genes are also linked, and analysis of globin genes in X. tropicalis suggests that this duplication of an alpha-beta-globin gene pair in X. laevis is the result of chromosome duplication by tetraploidization. The close linkage of alpha- and beta-globin genes in Xenopus provides evidence that vertebrate alpha- and beta-globin genes evolved by tandem duplication of a single primordial globin gene.
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D005796:Genes; D008040:Genetic Linkage; D005914:Globins / Q000235:genetics*; D011123:Polyploidy; D014981:Xenopus; D014982:Xenopus laevis
chemical_list: D005914:Globins; D004247:DNA