A cluster of four globin genes from the Antarctic fish Notothenia coriiceps

The blood of Channichthyidae, the most phyletically derived notothenioid fa mily, is devoid of haemoglobin (Nb). Three of the 15 channichthyid species retain inactive genomic remnants of the major adult notothenioid alpha -glo bin gene, but have lost the gene encoding adult beta -globin. In an attempt to understand the mutational events leading to loss of globin expression i n channichthyids, the organisation of globin genes in red-blooded nototheni oid species was examined. Globin genes in fish are often organised as alpha /beta pairs linked in 5' to 5' orientation, and the major adult alpha- and beta -globins of the Antarctic yellowbelly rockcod Notothenia coriiceps hav e this organisation. A second globin gene cluster from N. coriiceps contain s two sets of linked alpha- and beta -globin genes but the deduced amino ac id sequences of the globins differ from those of the adult globins. To lest the hypothesis that the globins may be expressed at different stages of on togenesis, total RNA from head kidney and erythrocytes of adult and juvenil e N. coriiceps were probed for transcripts corresponding to the four globin genes. The data suggest that the globin genes of this cluster are transcri bed maximally in the early phase of development. Southern analysis of the g enomes of red- and white-blooded notothenioids revealed that the genes of t his complex are absent in Hb-less icefish. (C) 2000 The Fisheries Society o f the British Isles.