Topic 5.2: Meiosis and Genetic Diversity

What does the correct separation of chromosomes in Meiosis I and II ensure for the gametes?

That each gamete receives a haploid (1n) set consisting of an assortment of both maternal and paternal chromosomes.

What is nondisjunction?

The incorrect separation of chromosomes/chromatids, resulting in gametes that are no longer haploid.

What is crossing over (recombination) and when does it occur?

The exchange of genetic material between non-sister chromatids during Prophase I.

Which three processes in eukaryotes increase genetic variation?

Crossing over, random assortment of chromosomes, and subsequent fertilization.

Non-sister chromatids

Chromatids belonging to different members of a homologous chromosome pair (one maternal, one parental)

Random assortment of chromosomes

The random orientation and distribution of homologous chromosomes pairs during metaphase I of meiosis

Subsequent fertilization

The fusion of haploid gametes (sperm and egg) produced during meiosis to form a diploid zygote