Now, notice along each one of these chromosomes, let's suppose along the darker green chromosome, we have two genes. And this red gene is linked to the blue gene in the same exact way that this orange gene is linked to the purple gene. So whenever two or more genes are found on the same chromosome, they are said to be linked to one another. So this gene right here, uppercase V, is linked to this here uppercase B, while this is linked to this right over here. Now, let's suppose that this particular fruit fly that has this homologous chromosome pair wants to produce gametes, so it wants to undergo reproduction and that means it wants to produce gametes. And the first step in producing gametes is to replicate the DNA during interface.