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Evolution and Molecular Characterization of a β-Globin Gene from the Australian Echidna Tachyglossus aculeatus (Monotremata)

✍ Scribed by Mi-Hye Lee; Robert Shroff; Steven J.B. Cooper; Rory Hope


Publisher
Elsevier Science
Year
1999
Tongue
English
Weight
174 KB
Volume
12
Category
Article
ISSN
1055-7903

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✦ Synopsis


Coinciding with a period in evolution when monotremes, marsupials, and eutherians diverged from a common ancestor, a proto-␤-globin gene duplicated, producing the progenitors of mammalian embryonic and adult ␤-like globin genes. To determine whether monotremes contain orthologues of these genes and to further investigate the evolutionary relationships of monotremes, marsupials, and eutherians, we have determined the complete DNA sequence of an echidna (Tachyglossus aculeatus) ␤-like globin gene. Conceptual translation of the gene and sequence comparisons with eutherian and marsupial ␤-like globin genes and echidna adult ␤-globin indicate that the gene is adult expressed. Phylogenetic analyses do not clearly resolve the branching pattern of mammalian ␤-like globin gene lineages and it is therefore uncertain whether monotremes have orthologues of the embryonic ␤-like globin genes of marsupials and eutherians. Four models are proposed that provide a framework for interpreting further studies on the evolution of ␤-like globin genes in the context of the evolution of monotremes, marsupials, and eutherians. 1999 Academic Press