The sequence of the genes will be ABCD, abCD and abCd, abcD.
Full question is attatched below.
<h3><u>Explanation:</u></h3>The genes in the chromosomes are denoted as the sequence of genes present in a single chromatid of a particular chromosome. Thus, the genes here in this question are to be mentioned as ABCD and not as abab.
Crossing over is the process by which the homologous pair of chromosomes do pair up in the Prophase 1 of meiosis 1 division and they exchange a particular part of their DNA with each other. This leads to exchange of genes between the homologous chromosomes, which will form different gametes in near future. This brings about a variation between the offsprings of same individuals.
Here the d gene of the two chromosomes are getting exchanged.
So the chromosomes will become ABCD, abCD and abCd, abcD respectively.
