Which aspect(s)of chromosome behaviour is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?
A) Segregation of sister chromatids at anaphase II of meiosis
B) Segregation of homologous chromosomes at anaphase I of meiosis
C) Crossing-over between homologous chromosomes during prophase I of meiosis
D) Independent alignment of different homologous pairs on the metaphase I spindle
E) Both crossing-over between homologous chromosomes during prophase I of meiosis and independent alignment of different homologous pairs on the metaphase I spindle contribute to genetic variability

Question

Quizplus · Accepted Answer

Both crossing-over between homologous chromosomes during prophase I of meiosis and independent alignment of different homologous pairs on the metaphase I spindle contribute to genetic variability. Crossing-over results in the exchange of genetic material between non-sister chromatids of homologous chromosomes, leading to the creation of new combinations of alleles. Independent alignment of different homologous pairs on the metaphase I spindle allows for random assortment of chromosomes into gametes, resulting in further genetic diversity. Segregation of sister chromatids at anaphase II and segregation of homologous chromosomes at anaphase I are necessary steps in meiosis, but do not introduce new genetic variability on their own.

Which Aspect(s)of Chromosome Behaviour Is/are Primarily Responsible for the Tremendous