So crossing over takes place as we know, during prophase I of meiosis. So when crossing over takes place, what basically happens is this piece of DNA here switches exchanges with this piece of DNA. And so what we produce are the following four chromosomes. So we have one, we have two, then we have exchange taking place, three, four, so nothing happens here. So this one basically remains the same. So we have uppercase t and this one also remains the same.