Question

Some plants fail to produce chlorophyll, and this trait appears to be recessive. If we locate a plant that is heterozygous for this trait, self-pollinate it, and harvest seeds, what are the likely phenotypes of these seeds when they germinate?A. All will be green with chlorophyll since that is the dominant trait.
B. All will be white and lack chlorophyll since this is self-pollinated.
C. About one-half will be green and one-half white since that is the distribution of the genes in the parents.
D. About one-fourth will be white and three-fourths green since it is similar to a monohybrid cross between heterozygotes.
E. About one-fourth will be green and three-fourths white since it is similar to a monohybrid cross between heterozygotes.

Answer 1

Answer: Option C) About one-half will be green and one-half white since that is the distribution of the genes in the parents

Explanation:

- Let the recessive trait (white) for inability to produce chlorophyll be "cc"

- Let heterozygous plant be "Cc"

So, two heterozygous plants self pollinated means Cc X Cc

Cc seperate to yield two alleles "C" and "c"

So, the cross of both:

"C", "c" X "C", "c"

Seeds will be CC, CC, cc and cc

From the crossing, the seed phenotypes are 50% green with "CC", and 50% white with "cc".

Thus, about one-half will be green and one-half white.