Question

Flower color in snapdragons is due to a gene with incomplete dominance: CRCR plants have red flowers, CRCW have pink flowers, and CWCW plants have white flowers. What types and ratios of flower color are expected among the progeny of a cross of pink × white?
a.1 red:2 pink:1 white
b.1 red:1 pink
c.1 pink:1 white
d. all pink
e. all white

Answer 1

Answer:

c.1 pink:1 white

Explanation:

Incomplete dominance is a genetic phenomenon whereby one allele of a gene is not completely dominant over the other allele, hence, it forms an heterozygous with an intermediate phenotype different from both parents. In this case of snapdragon plants, CRCR is the red allele while CWCW is the white allele. They form an intermediate phenotype that has pink flower colour; CRCW.

Hence, in a cross between a pink snapdragon (CRCW) and a white snapdragon (CWCW), four possible offsprings will be produced with two distinct genotypes: CRCW (2) and CWCW (2). Hence, this will give a ratio of 2:2 or 1:1 consisting of 1 pink : 1 white offspring.