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 (genetic recombination) is the process where homologous chromosomes pair up with each other and exchange different segments of genetic material to form recombinant chromosomes. It occurs between prophase 1 and metaphase 1 of meiosis. As an exception , it can ALSO OCCUR IN MITOSIS which may result in heterozygosity. But the frequency of crossing over is much higher in meiosis. Cross over events happen approximately 57 times in males and around 75 times in females during meiosis . Mitotic crossing over take place when homologous chromosomal segments are accidentally paired in asexual cells such as body cells.