Figure 1.

Gross appearance of morc mice. (Upper) The wild-type FVB (+/+) pink (albino) eye color contrasts with the brown (+/− mice) or black (−/− mice) eye pigmentation caused by one or two copies of the morc transgene, respectively. (Lower) A marked size reduction is noted in the −/− testis compared with +/+ or +/− testis. Epididymides were of similar size in all three genotypes (the normal epididymis was inadvertently removed from the +/− specimen). The +/− testis is slightly pigmented because of transgene expression (see text).