Question

If fruit flies, the allele for red eyes (R) is dominant and the allele for sepia eyes (r) is recessive. How can you determine the genotype of a male fruit fly with red eyes?

Answer 1

To determine the genotype of a male fruit fly with red eyes, we must observe the phenotype of offspring resulting from a cross with a sepia-eyed female. A Punnett square analysis of the offspring can suggest whether the male is homozygous dominant (RR) or heterozygous (Rr) for the eye color trait.

Step-by-step explanation:

To determine the genotype of a male fruit fly with red eyes, we must consider the inheritance patterns of the eye color trait in Drosophila melanogaster. Since red eye color (R) is dominant over sepia (r), a male fruit fly with red eyes could have either a homozygous dominant (RR) genotype or a heterozygous genotype (Rr). Without further genetic crosses or information, we cannot definitively determine the genotype of the male. However, if he is crossed with a female of known genotype, the phenotype of the offspring can provide insights into his genotype.

If a Punnett square is used to visualize the potential offspring from a cross between the red-eyed male and a sepia-eyed female (rr), the offspring ratios can help to reveal the male's genotype. For example, if any offspring have sepia eyes, the male must be heterozygous (Rr). If all offspring have red eyes, the male could be homozygous dominant (RR), but additional crosses would be needed to confirm this.