AP Biology· difficulty 3/5
AaBb × aabb (dihybrid test cross with independent genes) yields a phenotypic ratio of
1:1:1:1
3:1
1:2:1
9:3:3:1
Explanation
Each independent gene segregates 1:1 in the heterozygous parent. Combined: 1 AaBb : 1 Aabb : 1 aaBb : 1 aabb.
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