In the mouse, gene b can produce black pigment from a colorless precursor molecule. a mouse having at least one b allele can produce black pigment, whereas the homozygous recessive mouse (bb) cannot and is albino. the agouti locus (a) can convert the black pigment to brown in the presence of at least one dominant a allele, whereas the homozygous recessive (aa) cannot convert the black pigment to brown. what color fur would a mouse have with the genotype aabb