The chromatin structure is dynamic. In regions of highly condensed chromatin, such as the centromere, the boundary between heterochromatin and euchromatin is variable. Genes that are near this boundary region can be influenced by either type of chromatin in what is referred to as position effects.
Recall the early Drosophila melanogaster experiments by Hermann Muller where the repositioning of the w + allele (the normal activity of the w + allele produces red-eye pigment) by translocation or inversion near this boundary of chromatin produced intermittent w + activity. In the heterozygous state (w +/w), a variegated eye is produced, with white and red patches.
Which statements are true in relation to this experiment? Select all that apply.
a. Since the genotype is heterozygous, half of the cells will receive the w + allele producing red eye patches, while the other half will receive the w allele producing white patches.
b. When heterochromatin spreading does not reach the new location of the w + allele, the gene will be transcribed, producing red eye patches.
c. When heterochromatin spreading encompasses the new location of w + allele, the gene is transcribed, producing white eye patches.
d. Even though eye color phenotypic variegation exists within the eye, all cells have the same genotype.
e. When heterochromatin spreading encompasses the new location of w + allele, the gene is not transcribed, producing white eye patches.