The hairless gene allele, H, in fruit flies, causes fruit flies to lack sensory hairs. The H allele is dominant; the recessive allele, h, causes flies to have normal sensory hairs. The dominant allele is lethal when homozygous.
A second gene, suppressor of Hairless, Su(H), can block the phenotype of hairless. The dominant allele, Su(H), prevents the H allele from causing its phenotype, resulting in flies with sensory hairs. The dominant Su(H) allele is also lethal when homozygous. The recessive allele, su(H), allows the H allele to cause its phenotype. The Su(H) allele does not affect with the h allele.
A. If you were given a strain of flies which has normal sensory hairs, what are all the possible genotypes of this strain, with respect to these two genes described above?
B. If you were given a strain of flies with normal sensory hairs, how could you determine the genotype through crosses alone? Assume that you could set up a cross with any valid combination of the alleles listed in the introduction to this problem. Identify the conclusions you would make about genotypes based on the crossing scheme.
The hairless gene allele, H, in fruit flies, causes fruit flies to lack sensory hairs. The H allele is dominant; the recessive allele, h, causes flies to have normal sensory hairs. The dominant allele is lethal when homozygous.
A second gene, suppressor of Hairless, Su(H), can block the phenotype of hairless. The dominant allele, Su(H), prevents the H allele from causing its phenotype, resulting in flies with sensory hairs. The dominant Su(H) allele is also lethal when homozygous. The recessive allele, su(H), allows the H allele to cause its phenotype. The Su(H) allele does not affect with the h allele.
A. If you were given a strain of flies which has normal sensory hairs, what are all the possible genotypes of this strain, with respect to these two genes described above?
B. If you were given a strain of flies with normal sensory hairs, how could you determine the genotype through crosses alone? Assume that you could set up a cross with any valid combination of the alleles listed in the introduction to this problem. Identify the conclusions you would make about genotypes based on the crossing scheme.
