[2 pts] Question 6: A single nondisjunction event occurs during meiosis I in a male Drosophila fly. What are ALL the possible sex-chromosome genotypes and sex phenotypes of progeny that resulted from fertilization by one of the sperm produced by this round of meiosis with the nondisjunction occurring? Assume that the female egg fertilized has the expected wildtype sex chromosome genotype. To earn full credit you must correctly select ALL that are possible. Incorrect answers will deduct points.
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During meiosis I, if nondisjunction occurs, it means that the chromosomes do not separate properly, leading to an abnormal number of chromosomes in the resulting gametes. Show more…
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A single nondisjunction event of the sex chromosomes occurs during meiosis I in a male Drosophila fly that has white eyes. This male fly mates with a true-breeding red-eyed female fly. With respect to the sex chromosomes and white gene, what are the possible progeny genotypes that this meiotic error would result in, assuming no meiotic errors in the female parent fly (O = no sex chromosome)? To earn full credit, you must correctly select ALL that are possible. Xw+Xw XwY YY Xw+XwXw Xw+XwY YYXw+ XwO Xw+O
Madhur L.
For each of the following nondisjunction events, explain whether or not they could have produced an individual with Klinefelter's syndrome (47, XXY). For each event, state which sex chromosomes would be present in the sperm and the egg. In each case, assume that meiosis has proceeded normally in the other parent. HINT: draw out each case. Remember that in meiosis in XY individuals, the X and Y chromosomes pair in Meiosis I. a) Nondisjunction in meiosis I in the mother. b) Nondisjunction in meiosis II in the mother. c) Nondisjunction in meiosis I in the father. d) Nondisjunction in meiosis II in the father.
Katlin K.
5. Sometimes nondisjunction will occur in a parent that has normal chromosome numbers and result in an offspring that has abnormal number of chromosomes The phenotype of the affected offspring will often allow geneticists to determine in which parent and during which division of meiosis the nondisjunction occurred: In each of the examples below, assume the parents have normal diploid chromosome complement: EXAMPLE 1 Aman has a rare X-linked dominant condition called amelogenesis imperfecta, which results in weak brown tooth enamel: He marries a woman with normal teeth. They produce daughter with normal teeth: This daughter's normal teeth resulted from one nondisjunction event during the formation of either the egg or sperm _ In which parent did the nondisjunction occur? Explain b_ Did nondisjunction occur at meiosis | or II?
Adi S.
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