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The following cell completed interphase and replicated the chromosomes for meiosis. During the formation of gametes, the chromosomes failed to separate properly during meiosis. 

5 months ago

Answered By Arsalan Q

I imagine a picture is meant to go along with this question but i can explain part of it nonetheless. Failure for gamete production during meiosis is known as Nondisjunction. As you know Meiosis is broken up into Meiosis 1 and Meiosis 2 for gamete production. We can have nondisjunction at either step. If it occurs in meiosis 1, then instead of 4 gametes each with n amount of chromosomes (where 2n is the diploid chromosome count)  we get 4 gametes with chromosome counts of n+1, n+1, n-1, and n-1. if it occurs in meiosis 2 we get 4 gametes with chromosome coutns of n, n, n-1, and n-1. We're supposed to get 4 gametes with n chromosomes, but nondisjunction disrupts this. Notice how in both nondisjunctions, the amount of chromomes still add to 4n, the positive and negative ones cancel. what this should indicate is that nondisjunction cant create or destroy genetic information, only rearrange it imporoperly. Nondisjunction is a lack of arrangement. Additionally if n+1 gamate gets used in fertilization it results in trisomy, if the n-1 one gets used it results in monosmy

hope this helped :)