parents that are heterozygous for having freckles (dominant) are crossed. which correctly describes their…
parents that are heterozygous for having freckles (dominant) are crossed. which correctly describes their offspring?\ntwenty - five percent have freckles.\ntwenty - five percent are ff.\nseventy - five percent have freckles.\nseventy - five percent are ff.
Answer
Answer:
C. Seventy - five percent have freckles.
Explanation:
Step1: Determine the genotypes of parents
Let (F) represent the allele for freckles (dominant) and (f) represent the allele for no freckles (recessive). Heterozygous parents have the genotype (Ff).
Step2: Create a Punnett square
| Gametes of Parent 1 | Gametes of Parent 2 |
|---|---|
| (F) | (f) |
| (F) | (FF) |
| (f) | (Ff) |
Step3: Analyze the genotypes and phenotypes
- Genotypes: (FF:Ff:ff = 1:2:1)
- Phenotypes: Since (F) is dominant, (FF) and (Ff) show freckles. The proportion of offspring with freckles is (\frac{3}{4}=75%) (because (FF) and (Ff) are the genotypes for freckles).
- For option A: (25%) have freckles is wrong as (75%) have freckles.
- For option B: (25%) are (Ff) is wrong. The proportion of (Ff) is (50%) ((\frac{2}{4})).
- For option D: (75%) are (Ff) is wrong. The proportion of (Ff) is (50%).