Ristintö

Ristintö is a Finnish term that generally refers to the process of "crossing over" in genetics. This biological phenomenon occurs during meiosis, the type of cell division that produces gametes (sperm and egg cells). Specifically, ristintö describes the exchange of genetic material between homologous chromosomes.

Homologous chromosomes are pairs of chromosomes that carry genes for the same traits, one inherited from each parent. During a phase of meiosis called prophase I, these homologous chromosomes pair up. While paired, they can undergo a process called crossing over, where segments of DNA are broken and rejoined to the corresponding segment on the other chromosome. This exchange shuffles the genetic alleles, leading to new combinations of genes on each chromosome.

The significance of ristintö lies in its role in generating genetic diversity within a species. By creating new combinations of alleles, crossing over increases the variation among offspring. This variation is crucial for adaptation and evolution, as it provides a wider range of traits for natural selection to act upon. Without ristintö, offspring would inherit gene combinations that are identical to those of their parents, limiting the potential for evolutionary change. The term is primarily used in Finnish biological contexts.