Answer to Question #51269 in Biology for abby

Question

1. What are the consequences of fertilization of these abnormal gametes? Explains.

2. Explain why non-disjunction occurring during meiosis I is riskier (more consequences) non-disjunction occurring during meiosis II.

3. Explain how the chromosome disjunction process during meiosis is similar to the act of distributing playing cards

Answer 1

1. If one of these abnormal gametes undergoes fertilization, then a baby with an abnormal number of chromosomes in its cells could be born. It is due to excess or lack of chromosomes that carry all necessary genetic information for the whole organism development.
2. If the nondisjunction occurs during the first meiotic division (meiosis I), all the gametes derived will be abnormal. Half of them will contain neither members of the chromosome pair, while the other half will contain both homologous chromosomes. If nondisjunction occurs during anaphase II of meiosis II, it means that at least one pair of sister chromatids did not separate. In this scenario, two cells will have the normal haploid number of chromosomes.
3. Playing cards have been used to simulate production of recombinational variation resulting from meiosis by independent assortment of maternal and paternal chromosomes (for instance, the red-backed and blue-backed Queen of hearts are homologous chromosomes). For more details check here: Shumway, S.W. (1993). Meiosis and playing cards. The Science Teacher 60, 62-63.