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. So once we replicate the DNA, we form the following two homologous chromosomes. So now, instead of having a single chromatid, we have two cystochromatids is a cystochromatid to this. And because DNA replication produces identical pieces of chromosome, that means these two are identical chromosomes.