How does crossing-over occur in Meiosis?

Question

Gabriella Anderson · Accepted Answer

During metaphase I the paternal and maternal chromosomes line up at the equtor, and the homologous ones pair up. Two parts of the chromosomes, one paternal and one maternal join at a point called chiasmata.They both break at this point and the cut pieces are exchanged, i.e, the maternal cut goes to the paternal chromosome and vice versa.

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Elias Aboujaoude · Answer

undefined Crossing-over in meiosis occurs during prophase I. Homologous chromosomes pair up and exchange segments of genetic material. This exchange creates genetic diversity by mixing genetic information from the maternal and paternal chromosomes.

Vivian Aronson · Answer

undefined Crossing-over in meiosis occurs during prophase I. It involves the exchange of genetic material between homologous chromosomes. Here's how it happens:

1. Homologous chromosomes pair up during prophase I of meiosis. Each pair consists of one chromosome from the mother and one from the father.

2. As the homologous chromosomes pair up, they may undergo a process called synapsis, where they become closely aligned along their lengths.

3. During synapsis, segments of chromatids from homologous chromosomes may break and exchange places. These segments are called chiasmata.

4. The exchange of genetic material between chromatids results in a recombination of genes. This means that the chromosomes now carry a combination of genetic information from both parents.

5. After crossing-over, the homologous chromosomes may separate during the subsequent stages of meiosis, ensuring that each gamete receives a unique combination of genetic material.

Overall, crossing-over promotes genetic diversity by creating new combinations of alleles on chromosomes, which contributes to the variability seen in offspring resulting from sexual reproduction.