Question

What all happens on Prophase 1 of Meiosis 1

There are 3 ways that meiosis and sexual reproduction lead to genetic variation. Explain those 3 ways

Crossing over
Independent assortment of homologous chromosomes
Random fertilization

Answer 1

Crossing over: As mentioned above, crossing over during prophase 1 creates new combinations of alleles on the chromatids. This means that each gamete will have a unique set of genetic information.

Independent assortment of homologous chromosomes: During metaphase 1, the bivalents line up randomly along the metaphase plate. This means that each gamete will receive a random assortment of maternal and paternal chromosomes. There are 2^n possible combinations, where n is the number of chromosome pairs (23 in humans).

Random fertilization: During sexual reproduction, any gamete from one parent can fuse with any gamete from another parent. This adds another layer of randomness to the genetic makeup of the offspring. There are 2^n x 2^n possible combinations, where n is the number of chromosome pairs (23 in humans).

Step-by-step explanation:

Answer 2

rophase 1 is the first stage of meiosis 1, during which the following events occur:

Chromosomes condense and become visible as paired homologous chromosomes. Each chromosome consists of two sister chromatids held together by a centromere.

Non-sister chromatids of homologous chromosomes pair up and form a tetrad or bivalent.

Crossing-over occurs between non-sister chromatids of homologous chromosomes, resulting in exchange of genetic material between the homologous chromosomes.

The nuclear envelope breaks down, and spindle fibers attach to the kinetochores of the homologous chromosomes.

The three ways that meiosis and sexual reproduction lead to genetic variation are:

Crossing over: During meiosis 1, homologous chromosomes pair up and exchange segments of genetic material by crossing over. This creates new combinations of alleles on the chromosomes, leading to genetic variation in the resulting gametes.

Independent assortment of homologous chromosomes: During meiosis 1, homologous chromosomes align randomly on the metaphase plate, resulting in random segregation of maternal and paternal chromosomes into the daughter cells. This leads to a variety of possible combinations of chromosomes in the gametes.

Random fertilization: During sexual reproduction, any sperm can fertilize any egg. This leads to a random combination of alleles from the two parents, resulting in genetic variation in the offspring.