AAMC #9 question 144

[bullsfan1986]

I was looking over the thread "AAMC9 Q&A" but no one seems to have answered question #144 in BS.

The question reads:

If chromosomal duplication before tetrad formation occurred twice during spermatogenesis, while the other steps of meiosis proceeded normally, which of the following would result from a single spermatocyte?

a)one tetraploid sperm

b) four diploid sperm

c)four haploid sperm

d) eight haploid sperm

The answer is b.

I understand that if the cell goes through 2 duplications you will get double the amount of DNA as compared to a cell that only goes through one duplication and thus you'll get 4 haploid cells. I guess my real question is that during metaphase 1 instead of forming a tetrad, do you form an octatrad? (I made up that word.) And then that "octatrad" goes through normal meioisis and forms 4 diploid sperm? Hopefully that made sense. Thanks!

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[PiBond]

I was looking over the thread "AAMC9 Q&A" but no one seems to have answered question #144 in BS.

The question reads:

If chromosomal duplication before tetrad formation occurred twice during spermatogenesis, while the other steps of meiosis proceeded normally, which of the following would result from a single spermatocyte?

a)one tetraploid sperm

b) four diploid sperm

c)four haploid sperm

d) eight haploid sperm

The answer is b.

I understand that if the cell goes through 2 duplications you will get double the amount of DNA as compared to a cell that only goes through one duplication and thus you'll get 4 haploid cells. I guess my real question is that during metaphase 1 instead of forming a tetrad, do you form an octatrad? (I made up that word.) And then that "octatrad" goes through normal meioisis and forms 4 diploid sperm? Hopefully that made sense. Thanks!

it would make more sense to just have double the amount of tetrads at the metaphase plate. a theoretical "octatrad" would have had serious problems in recombination. regardless, i think AAMC was drawing on the student's ability to use POE on this question

 

[bullsfan1986]

Ah, makes sense. I wasn't even thinking recombination, good call. Thanks!