What is this genetics phenemenon called?

Question

In mice, the yellow coat color gene (y) is lethal in homozygous form...if a mouse receives the homozygous gene, what is that phenomenon called?

wesnaw: your credibility is? I'm only asking because it seems there's probably different term for it.

Here's the full question I need to answer:
In mice, the yellow coat color gene (y) is lethal in the homozygous form. YY individuals are brown, Yy individuals are yellow. When two heterozygous individuals are crossed, what would you expect to be the ratio of colors in their surviving offspring? What type of genetic phenomenon is this?

Answer 1

I think what you're looking for is "lethal dominant allele".

The yellow allele must be dominant to the brown if a single copy creates the yellow phenotype.

Answer 2

If there is a different term for it, we would need more info. Elaborate on the...., as of now it really can only be described as a recessive lethal mutation. Also, do you mean if a mouse receives just the mutant copy it is lethal, regardless of the status of the other allele? I ask since you use the term homozygous in two different ways, so maybe you mean hemizygous?

Answer 3

2 heterozygous = Yy x Yy =
YY
Yy
Yy
yy

so 25% brown
50 % yellow
25% would die

so of the surviving offspring:
33% brown
66% yellow

i think its just referred to as a lethal phenotype

Answer 4

A mouse can't receive a "homozygous gene" because homozygous only refers to an individual, not the gene.

Answer 5

its called lethal, thats it