Incomplete dominance Transitional Reasoning Download PDF

Questions

1. 1.

   A botanist crosses a true-breeding plant producing dark violet flowers with a true-breeding plant producing white flowers, and all resulting $F_1$ individuals display lavender flowers. When two of these lavender $F_1$ plants are crossed, they yield an $F_2$ generation containing a total of 240 offspring. Based on the mechanism of inheritance demonstrated in these crosses, which predicted phenotypic distribution will the botanist observe in the $F_2$ generation?

   • A) 180 dark violet and 60 white plants, because the dark violet allele is completely dominant over the white allele.
   • B) 120 dark violet and 120 white plants, because alleles segregate equally without producing intermediate forms in the second generation.
   • C) 60 dark violet, 120 lavender, and 60 white plants, because heterozygotes express an intermediate phenotype resulting in identical 1:2:1 phenotypic and genotypic ratios.
   • D) 240 lavender plants, because the blending of parental alleles permanently eliminates homozygous combinations in subsequent generations.