![]() The resulting cells after meiotic division 1 are diploid - but unlike mitotic divisions:īoth chromosome copies are derived from only one of the original chromosomes in the parent cell - i.e. The chiasmata are also important in holding the maternal and paternal homologs together until they are separated at anaphase 1.Ĭross-overs do not occur between non-sister chromatids, as they are separate.Īt anaphase of meiotic division 1, the maternal and paternal chromatids are separated, such that one daughter cell inherits one mostly paternal homolog, and the other one mostly maternal homolog.Īt anaphase one of each pair of chromosomes goes to each daughter cell, such that each daughter cell inherits one copy of the paternal chromosome, and one copy of the maternal chromosome - as in the diagram on the right hand side. These random cross-over events scrambles the genetic material of each of the chromosomes in the gametes, helping to produce diverse offspring. This exhange of genetic material between maternal and paternal chromosomes is known as 'genetic recombination'Įach cross-over between two non-sister chromatids is called a chiasma (plural 'chiasmata') Each cross-over between two non-sister chromatids is called a chiasma (plural 'chiasmata') On average, 2-3 cross-overs per chromosome occur for humans. ![]() In the long prophase of meiotic division 1, genetic material can 'cross over' between maternal and paternal pairs of chromosomes (non-sister chromatids). Homologous chromosomes duplicate, but remain separate. ![]() However, in meiosis, the two pairs of chromosomes (paternal and maternal) stay together on the spindle of the equator to form a bivalent (contains 4 chromatids) The arms of sister chromatids are glued together by a protein called 'cohesin'. Homologous chromosomes duplicate to form sister chromatids, as in mitosis.
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