Final answer:
If heterochromatin spreading does not reach the new location of the w+ gene, and it remains in the euchromatic region, the gene produces the dominant phenotype.
Step-by-step explanation:
If heterochromatin spreading does not reach the new location of the w+ gene, and it remains in the euchromatic region, the gene produces the dominant phenotype. In the case of the summer squash example given, if the heterochromatin does not spread to the new location of the W gene, the gene will still remain active and produce the dominant white fruit phenotype, regardless of the alleles present at the Y gene. This is because the dominant copy of the W gene is able to mask the expression of the Y gene, resulting in the production of white fruit.