Answer and explain. •In an organism with a diploid chromosome number of 2n=4 , assuming no crossing over, after meiosis: 1)How many genetically different gametes could be formed? 2)How many genetically different zygotes could be formed following the fertilization? 3)Answer 1) and 2) if 2n=6. Solution 1). If no crossing over occurs, all the gametes produced are similar to the parent. 2). Assuming no crossing over occurs after meiosis, all the zygotes formed are genetically identical..