Entry Exam Category: High School Equivalency Exams
Course: General Education Development (GED)
Exam: GED Science and Practice Test
Practice Question
Extract
Domestic cats exhibit a great variety of coat characteristics. Two important genes governing cat coat traits are the white masking gene and the gene for fur length. The alleles for these traits are:
W - dominant allele for white masking, produces solid white fur
w - recessive allele, produces colored fur
L - dominant allele for fur length, produces short hair
I - recessive allele, produces long hair
W - dominant allele for white masking, produces solid white fur
w - recessive allele, produces colored fur
L - dominant allele for fur length, produces short hair
I - recessive allele, produces long hair
The Punnett square below shows a cross between a male long-haired cat with white fur and a female short-haired cat with colored fur... what is the most likely number of long-haired kittens with colored fur?
Answer Choices
- A: 10
- B: 20
- C: 30
- D: 60
Correct Answer: A
Rationale: Assuming a dihybrid cross (Wwll x wwLL), the phenotypic ratio is 1:1:1:1 for 4 phenotypes. With 20 offspring, approximately 25% (5) would be long-haired with colored fur, but 10 is the closest reasonable option.