Chiasma (genetics) In genetics, a chiasma (pl. chiasmata) is the point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes. At a given chiasma, an exchange of genetic material can occur between both chromatids, what is called a chromosomal crossover, but this is much more frequent during meiosis than mitosis. In meiosis, absence of a chiasma usually result in improper chromosomal segregation and aneuploidy.
A cancer prevention diet is one that is high in fiber, low in fat (especially animal fat), and includes generous portions of fruits and vegetables. It also minimizes or excludes alcohol. The best diets are pure vegetarian diets.
One reason a vegan diet might not be optimal for people with rheumatoid arthritis is because of the potential for inadequate amounts of important nutrients, including calcium and vitamins D and B12. Vegan diets also exclude fish, including salmon and tuna, which are high in anti-inflammatory omega-3 fatty acids.