112 Meiosis

What is the outcome of asexual reproduction?

A single individual passes all of its genes to its offspring, resulting in offspring identical to the parents.

What is meiosis?

A type of cell division that reduces the number of chromosome sets from diploid (2n) to haploid (n), producing four genetically diverse daughter cells.

What are homologous chromosomes?

Pairs of chromosomes that are the same length and shape, carrying genes controlling the same inherited characters (alleles).

What is the diploid number for humans?

46 chromosomes, represented as 2n = 46.

How does crossing over contribute to genetic variability?

During prophase I of meiosis, crossing over occurs between non-sister chromatids, resulting in recombinant chromosomes that combine DNA from both parents.

What is independent assortment of chromosomes?

The random orientation of homologous chromosome pairs during metaphase I of meiosis, leading to the formation of genetically unique gametes.

What is aneuploidy?

A genetic condition characterized by an abnormal number of chromosomes, resulting from nondisjunction during meiosis.

What is the most common type of aneuploidy in humans?

Trisomy 21, also known as Down syndrome.

What occurs during meiosis II?

The second division of meiosis, where sister chromatids separate, resulting in haploid cells with unduplicated chromosomes.

What factors contribute to genetic variation in offspring?

Crossing over, independent assortment of chromosomes, random fertilization, mutations, and natural selection.