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Comment
. 2010 Dec 21;107(51):21953-4.
doi: 10.1073/pnas.1016298108. Epub 2010 Dec 13.

How an ancient genome duplication electrified modern fish

Edmund D Brodie 3rd  1
Affiliations
Comment

How an ancient genome duplication electrified modern fish

Edmund D Brodie 3rd. Proc Natl Acad Sci U S A. .
No abstract available

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Conflict of interest statement

The author declares no conflict of interest.

Figures

Fig. 1.
Fig. 1.
A whole-genome duplication occurred early in the evolution of teleost fish, producing duplicate copies of the sodium channel gene Scn4a that was expressed in skeletal muscle. The two sister genes, Scn4aa and Scn4ab, continued to be expressed in skeletal muscle and experienced purifying selection that maintained protein structure. Roughly 100 Myr later, the Scn4aa gene was co-opted into novel electric organs in two independent lineages of fish, the mormyroids in Africa and the gymnotiforms in South America. Coincident with this change of expression, Scn4aa experienced a sudden 10-fold increase in the strength of selection, whereas the sister gene, Scn4ab, did not. Selection fixed amino acid substitutions in identical regions (shown in red) of the NaV1.4a sodium channel in each fish lineage. Representative species and electric organ discharge are shown for momyroids (Campylomormyrus numenius; photo by J.P. Sullivan) and gymnotiforms (Sternopygus macrurus; photo by P.K. Stoddard).
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