in summer squash, two independently segregating autosomal genes determine fruit color. the dominant w produces white fruit while the recessive w allows the fruit to be colored. in a homozygous w/w individual, another gene controls color, with green (g) dominant to yellow (g). a white squash and a yellow squash are crossed and the f1 yielded 50% white fruit and 50% green fruit. what kind of gene interaction is in evidence here?