Select the incorrect pair.

Options

A. Incomplete dominance - Dog flower
B. Pleiotropy - Phenylketonuria
C. Female heterogametic - Grasshopper
D. Klinefelter's syndrome - XXY

Answer

To solve the question of selecting the incorrect pair, we will analyze each option provided in the video transcript step by step.

### Step 1: Analyze Incomplete Dominance
- **Definition**: Incomplete dominance occurs when the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes.
- **Example**: In dog flowers, we have red flowers (dominant) and white flowers (recessive). When these are crossed, the resulting heterozygous offspring exhibit pink flowers.
- **Conclusion**: This pair is correct as it accurately describes incomplete dominance in dog flowers.

### Step 2: Analyze Pleiotropy
- **Definition**: Pleiotropy is a phenomenon where a single gene influences multiple phenotypic traits.
- **Example**: Phenylketonuria (PKU) is a genetic disorder caused by a mutation in a single gene that affects multiple traits, including the metabolism of phenylalanine and can lead to mental retardation.
- **Conclusion**: This pair is correct as it accurately describes pleiotropy using phenylketonuria as an example.

### Step 3: Analyze Female Heterogamity
- **Definition**: Female heterogamity refers to a condition where females produce two different types of gametes (e.g., W and Z in some species).
- **Example**: This condition is observed in certain insects like butterflies and some other species. However, it is incorrectly stated that grasshoppers exhibit this condition.
- **Conclusion**: This pair is incorrect since grasshoppers do not exhibit female heterogamity; rather, it is observed in butterflies.

### Step 4: Analyze Klinefelter's Syndrome
- **Definition**: Klinefelter's syndrome is a genetic condition in males characterized by the presence of an extra X chromosome (XXY).
- **Characteristics**: Individuals with this syndrome often exhibit both male and female characteristics and may have fertility issues.
- **Conclusion**: This pair is correct as it accurately describes Klinefelter's syndrome.

### Final Conclusion
After analyzing all the pairs, the incorrect pair is the one related to female heterogamity, specifically stating that it is seen in grasshoppers. Therefore, the answer is:

**Incorrect Pair: Female Heterogamity - Grasshopper**

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