In a group of fruit flies, some individuals have a gray body and others have a black body. In this group, the gene for the body color trait has two alleles. The allele B is for a gray body, and the allele b is for a black body.

A certain fruit fly is from this group. This fruit fly's phenotype for the body color trait is a gray body. This fly's genotype for the body color gene is Bb.
Based on this information, complete the following statement.

The fruit fly is for the body color gene