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The following results of a cross between two individuals shown in the picture are: Which statement describes the children of the cross?

Correct answer: B. One is homozygous recessive and the other has a dominant phenotype but has a mother with a recessive phenotype.

  • A. One is homozygous dominant and the other has a dominant phenotype but has a mother with a recessive phenotype
  • B. One is homozygous recessive and the other has a dominant phenotype but has a mother with a recessive phenotype.
  • C. One is homozygous recessive and the other has a dominant phenotype but has a brother with a recessive phenotype.
  • D. One is homozygous recessive and another has a recessive phenotype. but has a father with a dominant phenotype.

Explanation

All statements describing the children's genetic combination and phenotype are wrong except B and C. One child is homozygous recessive with a recessive phenotype and the other is heterozygous with a dominant phenotype. Option A is wrong because it says one child is homozygous dominant whereas according to the box diagram, there is no possibility that a child will be homozygous dominant. Option D is wrong because it says one child, apart from one being homozygous recessive, has a recessive phenotype, which is wrong. Option C is wrong because it assumes the gender by saying "brother" but the question does not provide any evidence for what the gender of another offspring is.

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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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