Correct question:
if a nondisjunction occurs at anaphase I of the first meiotic division, what will the proportion of abnormal gametes (for the chromosomes involved in the nondisjunction)?
Answer:
100%
Explanation:
Nondisjunction at meiosis-I means that two homologous chromosomes of at least one homologous pair fail to separate from each other during anaphase-I. This would result in the formation of one cell with one extra chromosome and the other with one less chromosome by the end of meiosis-I. Meiosis-II in these two cells would maintain this chromosome number in the daughter cells. Therefore, out of the total four gametes formed by the end of the meiosis, two would have one extra chromosome and would be denoted as "n+1". The rest of the two gametes would have one less chromosome and would be denoted as "n-1".
Answer:
Megaloblastic anemia is most often due to hypovitaminosis, specifically vitamin B12 (cobalamin) and folate deficiencies, which are necessary for the synthesis of DNA. [3] Copper deficiency and adverse drug reactions (due to drug interference with DNA synthesis) are other well-known causes of megaloblastic anemia.
Explanation:
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