While it is well understood that the evolution of new genes leads to adaptations that help species survive, gene loss may also afford a selective advantage. Scientists identified 26 losses of long-established genes, including 16 that were not previously known. Next they compared the identified genes in the complete genomes of the human, chimpanzee, rhesus monkey, mouse, rat, dog, and opossum to estimate the amount of time the gene was functional before it was lost. This refined the timing of the gene loss and also served as a benchmark for whether the gene in question was long-established, and therefore probably functional, or merely a loss of a redundant gene copy. Through this process, they found 6 genes that were lost only in the human.
More...