Question

Crossing over involves the physical exchange of DNA between chromatids. Group of answer choices True False

Answer 1

Cross over is also known as chromosomal crossing over.It is the exchange of genetic material between two homologous chromosomes non-sister chromatids that results in recombinant chromosomes during sexual reproduction.

A couple of homologous chromosomes, or homologs, are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during fertilization. Homologs have the same genes in the same loci where they provide points along each chromosome which enable a pair of chromosomes to align correctly with each other before separating during meiosis and a sister chromatid may also be said to be 'one-half' of the duplicated chromosome.

Cross over is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a process called synapsis. Synapsis begins before the synaptonemal complex develops and is not completed until near the end of prophase I. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome.

Crossing over and DNA repair are almost same process which utilize many of the same protein complexes. DNA repair and crossover have been found to favor similar regions on chromosomes.