Inherited traits and variation Transitional Reasoning Download PDF

Questions

1. 1.

   A biology student observes that two feline siblings from the same litter share the same biological parents but display completely different combinations of coat pattern and eye color. Genetic analysis reveals that both parents are heterozygous for these two unlinked autosomal traits (CcEe). Based on the mechanisms of meiosis and sexual reproduction, which explanation correctly accounts for the phenotypic differences between the two siblings?

   • A) Mitotic divisions during early embryonic development exchanged alleles between non-homologous chromosomes, altering the somatic genotypes of the offspring.
   • B) DNA replication during the S phase of interphase doubled the allele dosage, causing spontaneous mutations in both parental germlines.
   • C) Independent assortment of maternal and paternal chromosomes during metaphase I combined with random fertilization produced novel allelic combinations in each sibling.
   • D) Crossing over between identical sister chromatids during metaphase II permanently rearranged the nucleotide sequences of the inherited traits.