Question

In plants, genes E, F, and G are on one chromosome arm. Alternate dominant and recessive alleles of these three genes determine visible traits: E = normal leaf number, e = extra leaves; F = normal stems, f = furry stems; G = normal flower size, g = gigantic flowers. (Dominant alleles are in capital letters, and recessive alleles in small letters.) If one breakpoint disrupts the E gene by splitting it into two parts causing recessive loss of function, which chromosomal rearrangement could produce a phenotype similar to that seen in homozygous inversion? Select all that apply.

a) Homozygous deletion of E gene

b) Heterozygous inversion of E gene (as described in the question)

c) Homozygous duplication of E gene

d) Homozygous translocation where the breakpoint lies outside the E gene (with no effect on gene expression)

e) Homozygous translocation where the breakpoint is within the E gene as shown above

Answer 1

The correct answers are options b and c. A chromosomal rearrangement such as a heterozygous inversion or homozygous deletion of the E gene can produce a phenotype similar to homozygous inversion.

Step-by-step explanation:

A homologous inversion is a chromosomal rearrangement where a segment of the chromosome is flipped and reinserted in the opposite direction. In this case, if the E gene is disrupted by a breakpoint, it would result in the loss of function of that gene. To produce a phenotype similar to homozygous inversion, the chromosomal rearrangement that could occur is a heterozygous inversion of the E gene. Additionally, a homozygous deletion of the E gene could also produce a similar phenotype. Therefore, options b) and c) are correct.