Department of Molecular Genetics, Microbiology and Immunology, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA. paul.copeland@umdnj.edu
A recent analysis of sequences derived from organisms in the Sargasso Sea has revealed a surprisingly different set of selenium-containing proteins than that previously found in sequenced genomes and suggests that selenocysteine utilization has been lost by many groups of organisms during evolution.