AP BIOLOGY

Detailed explanation-1: -Crossing over is the exchange of genetic materials between non-sister chromatids of homologous chromosome . It takes place at pachytene stage of prophase-I.

Detailed explanation-2: -Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes’ non-sister chromatids that results in recombinant chromosomes.

Detailed explanation-3: -Crossing over, as related to genetics and genomics, refers to the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during the development of egg and sperm cells (meiosis).

Detailed explanation-4: -Meiotic recombination between artificial repeats positioned on nonhomologous chromosomes occurs efficiently in the yeast Saccharomyces cerevisiae. Both gene conversion and crossover events have been observed, with crossovers yielding reciprocal translocations.

Detailed explanation-5: -Non-sister chromatids are used to demonstrate crossing over because if sister chromatids did go through crossing over, they would be sharing the same/practically identical genetic information with each other, which is not the purpose of crossing over.