So this is the precursor cell that eventually gives rise to four X cells. Now, because we're dealing with a normal female individual, we have two X chromosomes, x chromosome number one and X chromosome number two. Now, during interface, before meiosis actually takes place, each one of these X chromosomes is actually replicated. So we have this X chromosome number one, and it's identical cystochromatid and X chromosome number two, and it's identical replicated cystochromatid. So we have a pair of these cystochromatids. So we have interface taking place and then meiosis begin.