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This is an accepted version of this page This is the latest accepted revision, reviewed on 26 January 2025. Cell division producing haploid gametes For the figure of speech, see Meiosis (figure of speech). For the process whereby cell nuclei divide to produce two copies of themselves, see Mitosis. For excessive constriction of the pupils, see Miosis. For the parasitic infestation, see Myiasis ...
Studies in male mouse meiosis have shown that after DNA damaging treatments like gamma irradiation, two types of repair responses occur depending on the meiotic stage: [5] From leptotene to early pachytene, exogenous DNA damage triggers widespread presence of the repair protein gammaH2AX in the nucleus, associated with homologous recombination ...
Meiosis involves two rounds of chromosome segregation and thus undergoes prophase twice, resulting in prophase I and prophase II. [12] Prophase I is the most complex phase in all of meiosis because homologous chromosomes must pair and exchange genetic information. [3]: 98 Prophase II is very similar to mitotic prophase. [12]
In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and meiosis II are specialized forms of cell division occurring during generation of gametes (eggs and sperm) for sexual reproduction, mitosis is the form of cell division used by all other cells ...
The grasshopper Melanoplus femur-rubrum was exposed to an acute dose of X-rays during each individual stage of meiosis, and chiasma frequency was measured. [23] Irradiation during the leptotene-zygotene stages of meiosis (that is, prior to the pachytene period in which crossover recombination occurs) was found to increase subsequent chiasma ...
Homologous recombination is the principal mechanism of DNA repair acting during meiosis. From the leptotene to early pachytene stages of meiosis exogenous damage triggered the massive presence of gamma H2AX (which forms when DNA double-strand breaks appear), H2AX was present throughout the nucleus, and this was associated with DNA repair ...
Meiosis is a round of two cell divisions that results in four haploid daughter cells that each contain half the number of chromosomes as the parent cell. [10] It reduces the chromosome number in a germ cell by half by first separating the homologous chromosomes in meiosis I and then the sister chromatids in meiosis II .
Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion. [1] Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one paralogous DNA sequence converts another.