FIG. 6.

Postnatal sir2α null animals are developmentally abnormal. sir2α null animals on the outbred background often survived past weaning but were characterized by a number of common developmental defects. Null animals were smaller than their littermates (both wild type and heterozygotes), and all null animals failed to open one or both eyelids. The snout of sir2α null animals was often shorter than normal. The photographs show sir2α null animals of various ages along with their normal littermates.