what is chiasmata?? plz explain in simple words
During prophase of meiosis the two homologous chromosomes are seen to be joined at several points along their length. These points are called chiasmata (chiasma, a cross). Each chiasma is the site of an exchange between chromatids. It is produced by breakage and reunion between any two of the four strands present at each site. As a result, genes from one chromosome may swap with the genes from other chromosome leading new gene combination in the resulting chromatids.
A chiasma (plural: chiasmata), in genetics, is thought to be the point where two homologous non-sister chromatids exchange genetic material during chromosomal crossoverduring meiosis (sister chromatids also form chiasmata between each other, but because their genetic material is identical, it does not cause any change in the resulting daughter cells). The chiasmata becomes visible during the diplotene stage of prophase I of meiosis, but the actual "crossing-over" of genetic material is thought to occur during the previous pachytene stage. When each bivalent (tetrad), which is composed of two pairs of sister chromatids, begins to split, the only points of contact are at the chiasmata.