AP BIOLOGY

Detailed explanation-1: -Crossing over was described, in theory, by Thomas Hunt Morgan. He relied on the discovery of Frans Alfons Janssens who described the phenomenon in 1909 and had called it “chiasmatypie". The term chiasma is linked, if not identical, to chromosomal crossover.

Detailed explanation-2: -Meiosis is a multi-step process in which a cell with a set of chromosomes creates four new cells with half that set. During meiosis, there is an important step to genetic variation. This step is called crossing over, or a crossover, and is unique to gametes.

Detailed explanation-3: -According to an attractive theory proposed by Darlington (1935) crossing-over is related to chromosome coiling. Two homologous chromosomes which are unwinding their relic coils pair in such a way that their internal and relational coils reach equilibrium.

Detailed explanation-4: -This process, also known as crossing over, creates gametes that contain new combinations of genes, which helps maximize the genetic diversity of any offspring that result from the eventual union of two gametes during sexual reproduction.

Detailed explanation-5: -Crossing over is a process that takes place during prophase-I of meiosis-I, in which non-sister chromatids of homologous chromosomes exchange segments between themselves. This exchange of segments is referred to as crossing over.