Monterey Bay Aquarium Research Institute
Seminars

 

A genomic fossil provides clues to hemoglobin loss in Antarctic icefishes

H. William Detrich III, Ph.D.
Northeastern University

Wednesday, September 6, 2006
Pacific Forum – 3:00 p.m.

Possession of hemoglobin in red blood cells is virtually synonymous with vertebrate life. The only vertebrates that lack these “essential” traits are 16 species of Antarctic icefishes (Notothenioidei: Channichthyidae). My lab has shown that several icefish species have lost the adult ß-globin gene but retain a 5’-truncated a-globin pseudogene.

This loss of hemoglobin expression could be the direct result of this deletion of the the adult ß-globin gene in the ancestral icefish or other mutational events could have preceded the adult ß-globin gene deletion. This seminar demostrates phylogenetically derived icefish, Neopagetopsis ionah, possess a nearly complete, but non-functional, adult aß-globin complex that includes two ß-globin pseudogenes. The ß-globin pseudogenes have distinctly different phylogenetic origins that span the most recent common ancestor of the entire Antarctic notothenioid radiation, indicating that one of the Neopagetopsis ionah ß-globin pseudogenes arose through introgressive hybridization. We conclude that in the Neopagetopsis ionah pseudogene cluster is a “genomic fossil” that reveals a key component in globin gene loss by the icefishes.

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