A student crosses true-breeding white-eyed Drosophila females with red-eyed males. The reciprocal cross uses red-eyed females and white-eyed males. F1 from cross 1: all females red-eyed, all males white-eyed. F1 from cross 2: all F1 red-eyed regardless of sex.
What does this pattern reveal?
- A
Maternal cytoplasmic inheritance
- B
Y-linked inheritance
- Ccheck_circle
The eye-color gene is X-linked recessive (red dominant)
- D
The gene is autosomal recessive
Explanation
The reciprocal-cross asymmetry (results differ depending on which parent carries which allele) is the hallmark of sex linkage. White-mother x red-father gives white sons (XwY) and red daughters (XwXr) - classic X-linked recessive.