Question

Because stubble is a dominant mutation and curled is recessive, one should use a male who is homozygous for recessive alleles at the curled locus, but homozygous wildtype at the stubble locus?

1) + cu/ + cu
2) + cu/ + st
3) + st/ + cu
4) + st/ + st

Answer 1

The correct genotype for a male with homozygous recessive alleles for curled wings and homozygous wildtype for stubble in Drosophila is '+ cu/ + cu' which represents a combination of wildtype stubble alleles and homozygous recessive curled alleles.

Step-by-step explanation:

The direct answer for the genetic combination needed to select a male with homozygous recessive alleles at the curled locus and homozygous wildtype at the stubble locus is: 1) + cu/ + cu.To produce offspring with the desired combination of traits, one should use a male who is homozygous for recessive alleles at the curled locus and homozygous wild-type at the stubble locus. This means that the genotype of the male should be +cu/+cu and +st/+st. This ensures that all the offspring will inherit the recessive curled allele and the dominant wild-type stubble allele.

An explanation for this answer involves understanding Mendelian genetics. Stubble is a dominant mutation, represented by 'st', while 'cu' signifies the recessive curled mutation. The homozygous wildtype for stubble would be '++', and since we need a homozygous recessive for curled, the genotype should be 'cu cu'. Combining both requirements, the genotype of the male should have wildtype stubble and homozygous recessive curled; hence the correct option is '+ cu/ + cu', where '+' represents the wildtype allele for stubble.