Final answer:
A heterozygous genotype for round eyes would be 'Rr'. In a cross between a white-eyed male and a heterozygous red-eyed female, 50% of male offspring will have red eyes, 50% will have white eyes, 50% of female offspring will be heterozygous with red eyes, and 50% will have white eyes.
Step-by-step explanation:
If an alien was heterozygous for round eyes, its genotype would consist of two different alleles: one for round eyes (which we can denote as 'R') and one for the alternative trait, which is not specified in the question (which we can denote as 'r'). Thus, the alien's genotype would be 'Rr'.
To address the question about the offspring from a cross between a white-eyed male and a female heterozygous for red eye color, we need to consider the principles of Mendelian genetics. If the trait for eye color follows simple Mendelian inheritance with red eyes being dominant (let's denote this allele as 'R') and white eyes being recessive (denoted as 'r'), and considering that the white-eyed male would have a genotype of 'rr', while the heterozygous red-eyed female would have a genotype 'Rr', we can construct a Punnett square to determine the expected ratios of offspring.
The cross would result in the following genotypes:
- 50% of the male offspring would be hemizygous dominant with red eyes (XRY)
- 50% of the male offspring would be hemizygous recessive with white eyes (XrY)
- 50% of the female offspring would be heterozygous with red eyes (XRXr)
- 50% of the female offspring would be homozygous recessive with white eyes (XrXr)