Meiosis - Wikipedia, the free encyclopedia

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** Meiosis **

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Not to be confused with Mitosis, Miosis, Myositis. Note that /mitosis/ is
the process by which most cells divide to produce two copies of themselves.
For the figure of speech, see Meiosis (figure of speech).
In meiosis, the chromosomes duplicate (during interphase) and homologous
chromosomes exchange genetic information (chromosomal crossover) during the
first division, called meiosis I. The daughter cells divide again in
meiosis II, splitting up sister chromatids to form haploid gametes. Male
and female gametes fuse during fertilization, creating a diploid cell with
a complete set of paired chromosomes.
File:Calyculin-A-an-enhancer-of-myosin-speeds-up-anaphase-chromosome-movement-1475-9268-6-1-S1.ogvPlay
media
A video of meiosis I in a crane fly spermatocyte, played back at 120×
the recorded speed.

*Meiosis* Listen^i/maɪˈoʊsᵻs/ is a specialized type of cell
division that reduces the chromosome number by half. This process occurs in
all sexually reproducing single-celled and multicellular eukaryotes,
including animals, plants, and fungi.^[1]^[2]^[3]^[4] Errors in meiosis
resulting in aneuploidy are the leading known cause of miscarriage and the
most frequent genetic cause of developmental disabilities.^[5]

In meiosis, DNA replication is followed by two rounds of cell division to
produce four potential daughter cells, each with half the number of
chromosomes as the original parent cell. The two meiotic divisions are
known as /Meiosis I/ and /Meiosis II/. Before meiosis begins, during S
phase of the cell cycle, the DNA of each chromosome is replicated so that
it consists of two identical sister chromatids, which remain held together
through sister chromatid cohesion. This S-phase can be referred to as
"premeiotic


Source: en.wikipedia.org/wiki/Meiosis


when is dna replicated in meiosis

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