The mating of an Aa male and an aa female produced an offspring with the genotype aaa. Therefore, the resulting offspring has 3 copies of gene 1 (trisomy for chromosome 1). At what stage during meiosis did the non-disjunction event occur and in which parent? There may be multiple answers.
a. Paternal non-disjunction in meiosis I
b. Materinal non-disjunction in meiosis I
c. Paternal non-disjunction in meiosis II
d. Maternal non-disjunction in meiosis II
b, c, d
The female sign points (down/up) and the male sign points (down/up).
Down; up
