In 1905, the French biologist Lucien Cuenot discovered an interesting mutant mou
ID: 226900 • Letter: I
Question
In 1905, the French biologist Lucien Cuenot discovered an interesting mutant mouse displaying a yellow coat color. He bred the mouse and its progeny for several generations but could never obtain a pure breeding stock of yellow mice! Normal mice have a coat color called Agouti which appears gray. When he crossed pure breeding gray Agouti mice with the yellow mouse, half the progeny had the gray Agouti coat and half had the light yellow coat. When he crossed the F1 yellow mice with each other, he found that 1/3 of the F2 progeny had the gray Agouti coat and 2/3 had the yellow coat. When he crossed the F2 yellow progeny with pure breeding Agouti mice, he found again that they produced 50% gray Agouti mice and 50% yellow mice. Based on these results, you would conclude that relative to the Agouti coat color, the Yellow coat color is: (circle the best single answer) Completely Dominant/Incompletely Dominant/Co-dominant/Incompletely Penetrant/Recessive Cuenot was never able produce a pure strain of yellow mice even after trying several for several years. Provide a one-sentence explanation for why Cuenot was unable to obtain yellow mice but not a breeding stock of yellow mice. The following pedigree shows transmission of a well-characterized dominant disease However, one part of the pedigree is unusual for a dominant trait. Circle the pedigree that is unusual and provide a one sentence explanation for how a dominant trait could exhibit this unusual pattern.Explanation / Answer
5 a. the pattern of inheritance is said to be incomplete dominance and the yThe allele causing yellow color is dominant for coat color. However, in terms of viability, the allele is recessive. This the alleles is pleotrophic as itaffects two or more distinct traits.
b. The gene for yellow color is recessive lethal and hence when present in homozygous recessive condition, cause inviability or death of the homozygous individuals