Question

Which of the following offspring genotypes could result from fertilization of a normal haploid sperm with an oocyte that had undergone nondisjunction in meiosis I1? (Because a nondisjunction event in meiosis II could involve the chromosome containing gene A or the chromosome containing gene a, be sure fo consider both possibilities in your final answer ) Select all that apply.

Answer 1

Question is incomplete I have added picture of full question as attached.

Answer with Explanation:

In meiosis 1, chromosome having gene A and its homologous part having same gene would have separated. While, in meiosis 2, separation of sister chromatids take place. If there is any non-dis-junction happens will results in migration of sister chromatid into same daughter cell.

If this happens there will be two possibilities.

Firstly, production of gametes having two copies of gene A or No copy due to non-dis-junction. while in normal cell each daughter cell will have one copy of gene a in it.

Secondly, same process happens with gene a in non-dis-junction. while normally each cell have only one copy of gene a.

By considering this fact there are following offspring genotypes will be produced.

AAa

aaa

Aa

aa

oa.