Cialis redirects here. For the Central Asian kingdom, see Karasahr. Tadalafil (INN) is a PDE5 inhibitor marketed in pill form for treating erectile dysfunction (ED) under the name Cialis see-AL-iss, and under the name Adcirca ad-SUR-kuh for the treatment of pulmonary arterial hypertension.
Quick Answer. The synapsis process occurs in the prophase I stage of meiosis. In synapsis, replicated homologous chromosomes link, which become known as a tetrad. Crossover between two pairs of tetrads can occur at any time. Continue Reading.
Crossing over. Definition. noun. A process occurring during meiosis wherein two chromosomes pair up and exchange segments of their genetic material. Supplement.This occurs at the stage when chromatids of homologous chromosomes pair up during synapsis, forming X-structure (chiasma).rossing over is important because it results in new combinations of genes that are different from either parent, contributing to genetic diversity. See also: meiosis, homologous chromosomes.