1. Long wings (L) in fruit flies is dominant to short wings (l). If you had a fruit fly with long wings, what mating would you set up to test if it was LL or Ll genotype?

Question

2. Jane's mother died of Huntington's disease (a dominant disorder): Jane says she is not worried about getting the disease because she knows her dad does not have the disease. How would you explain to Jane her risk of the disease?

3. When the parents are *always* normal , but their children are affected by a disease, does this indicate transmission via the dominant or the recessive? I think that it is the recessive.

Answer 1

1. Mate with an Ll. If about 25% offspring are short-winged, it is also Ll. If none, it is LL.

2. If dominant, only one gene is needed for the disorder. If mom is heterozygous, her chances are 50%, if homozygous, certainty.

3. Right. If both parents are only carriers for the recessive gene, they will not have the disease, but the children will have a 25% chance of getting it.

Answer 2

I'm looking for an answer to this question
In fruit flies the allele for long wings (L) is dominant and the allele for short wings (l) is recessive. What is the likely genotype of a fruit fly with long wings?
Either LL or Ll
Either Ll or ll
Only LL
Only ll