Question

which of thomas hunt morgan’s hypotheses was valid based on these results?
○ white eyes are lethal in female drosophila.
○ white eyes are lethal in male drosophila.
○ female drosophila with white eyes are homozygous recessive.
○ white eyes are the dominant trait in female drosophila.
(the question includes a punnett square chart with drosophila illustrations and genetic notation: x^r, y, x^r, x^r, showing genotypes x^r x^r, x^r y, x^r x^r, x^r y.)

Explanation:

1. Analyze the Punnett square: Female genotypes are \(X^R X^r\) (red eyes, since \(R\) is dominant), males are \(X^r Y\) (white eyes). No female with white eyes (\(X^r X^r\)) is present, suggesting \(X^r X^r\) (homozygous recessive for white eyes) isn't viable or shown, but the key is the third option: Female Drosophila with white eyes are homozygous recessive. Let's check others:

• First option: No info on lethality in females here.
• Second option: Males with white eyes (\(X^r Y\)) are present, so not lethal.
• Fourth option: Females have red eyes (dominant is \(R\)), so white isn't dominant.
• Third option: For a female to have white eyes, she needs two \(X^r\) alleles (homozygous recessive), which aligns with X - linked inheritance (Morgan's work on Drosophila eye color, X - linked recessive).

Answer:

Female Drosophila with white eyes are homozygous recessive.