A cross is made between two pure-breeding wheat strains, one with dark red kernels and the other with white kernels. The F₁ plants produced pink kernels, and when the F₁ plants were self-fertilized, the F₂ generation had 9 white, 12 dark red, 39 red, 41 light pink, and 59 pink kernels. What is the likely number of genes involved in the determination of kernel color in this population?