Two animals are mated. One is homozygous dominant for one character and homozygous recessive for another. The other animal Is heterozygous for both characters. How many phenotypes are expected in the offspring of this cross?
Correct answer: B. 2
- A. 1
- B. 2
- C. 3
- D. 4
Explanation
To understand and solve this, you can divide your thinking into two. For character 1. When genes are passed down to offspring, when the genes of this character pass down, the Dominant gene will always be present, so only one phenotype is possible from this character. For character 2. Three genotypes are possible, RR, Rr, and rr. RR and Rr are one phenotype and rr another. Total 2 So 2*1=2 total phenotypes
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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