Drosophila may be monosomic for chromosome 4, yet remain fertile. A recessive mutant for bent bristles is identified on chromosome 4. Determine the genotypes of the F1 and F2 progeny for the following crosses.
The following cross is conducted of true-breeding adult flies: monosomic bent bristles x diploid normal bristles. Select the two F1 genotypes that will be produced from this cross
a. -/b+
b. -/b
c. b/b
d. b/b+
e. b+/b+
b+ - the allele for normal bristles b - the allele for bent pristles
Monosomic means there is only one instead of two alleles in a gene locus. So, the parents' genotypes are: monosomic bent bristles: -/b diploid normal bristles: b+/b+
The following cross is conducted of true-breeding adult flies: Parents' phenotype: monosomic bent bristles x diploid normal bristles Parents' genotype: -/b x b+/b+ F1 generation: -/b+ -/b+ b/b+ b/b+
