Biology: genetic terms: homologous recombination

Tutoring biology, genetic terms come up. The tutor mentions homologous recombination.

Homologous recombination happens when a segment of foreign DNA is brought in to replace the corresponding local DNA. Perhaps the easiest case to think of is when two DNA strands each sever corresponding sections, then exchange them, so each receives some of the other’s DNA. The “homologous” idea means that, theoretically, the foreign DNA includes the same genes it’s replacing, although not necessarily the same versions of those genes. (A non-genetic example might be that person A and person B exchange phones. They’re both phones, but not necessarily the same kind.)

In the “crossing over” stage of meiosis, homologous recombination occurs as exchanges between pairs of DNA strands. However, homologous recombination can happen in other cases besides meiosis, especially in bacteria: Sometimes a foreign DNA fragment just shows up and replaces a corresponding segment in a longer strand. The replaced fragment is ejected from the strand, perhaps for uptake at a later time in another event of homologous recombination.

Homologous recombination drives genetic variety.

Source:

bio.libretexts.org

genome.gov