In a testcross AaBb x aabb, 90% of the progeny is like parents. Determine:
Are the genes linked?

Explanation

To determine whether the genes are linked in the testcross AaBb x aabb, we can follow these steps:

### Step 1: Understand the Testcross
A testcross involves crossing an individual with a dominant phenotype (but unknown genotype) with a homozygous recessive individual. In this case, we have AaBb (heterozygous for both traits) crossed with aabb (homozygous recessive for both traits).

**Hint:** Remember that a testcross helps reveal the genotype of an individual with a dominant phenotype.

### Step 2: Determine Expected Progeny Ratios
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