Genetic Variation: Random Assortment- Gracie Goodman

The behavior of chromosomes during meiosis and fertilization is responsible for most of the variations that arise each generation. Three mechanisms contribute to genetic variation; independent assortment, crossing over, and random fertilization. Independent assortment of chromosomes contribute to genetic variability due to the random orientation of tetrads at the metaphase plate. Each homologous pair of chromosomes is positioned independently of the other pairs at metaphase 1. However, crossing over produces recombinant chromosomes which combine genes inherited from each parent. Crossing over begins very early in prophase 1 as homologous chromosomes pair up gene by gene. The random nature of fertilization adds to the genetic variation arising from meiosis.


I was quite surprised that there are so many things that go into genetic variation like how there is a fifty-fifty chance that a particular daughter cell of meiosis 1 will get the maternal chromosome of a certain homologous pair and a fifty-fifty chance that it will receive the paternal chromosome. It's interesting that all three mechanisms reshuffle the various genes carried by individual members of a population.

References

N.p., 2016. Web. 14 Oct. 2016.
Help, Homework. "How Does Segregation Help Increase Genetic Diversity? | Enotes". eNotes. N.p., 2015. Web.
14 Oct. 2016.