AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

YELLOW FUR IN MICE

Semi dominant lethal : (Incompletely dominant lethal, intermediate lethal)

• In 1905, Cuenot, a French zoologist found that when yellow mice were mated inter se, they never bred true to type and yielded “yellow” and “non-yellow” progeny in the ratio of 2:1.
• Backcross of yellow into non-yellow yielded a ratio of 1:1.
• After more experimentation, it was eventually realized that all yellow mice were heterozygote and those zygotes homozygous for yellow died at an early stage of gestation.
• Thus the yellow mice provided the first demonstration where genes could be lethal in the homozygous state.

To view "Lethal Genes - Yellow Fur in Mice Animation"