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Ndt80 is a meiosis-specific transcription factor required for successful completion of meiosis and spore formation. [17] The protein recognizes and binds to the middle sporulation element (MSE) 5'-C[AG]CAAA[AT]-3' in the promoter region of stage-specific genes that are required for progression through meiosis and sporulation.
A video of meiosis I in a crane fly spermatocyte, played back at 120× the recorded speed. Meiosis (/ m aɪ ˈ oʊ s ɪ s / ⓘ; from Ancient Greek μείωσις (meíōsis) ' lessening ' (since it is a reductional division)) [1] [2] is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes ...
During the phase of meiosis labeled “interphase s” in the meiosis diagram there is a round of DNA replication, so that each of the chromosomes initially present is now composed of two copies called chromatids. These chromosomes (paired chromatids) then pair with the homologous chromosome (also paired chromatids) present in the same nucleus ...
Meiosis generates genetic variation in the diploid cell, in part by the exchange of genetic information between the pairs of chromosomes after they align (recombination). Thus, on this view, [28] an advantage of meiosis is that it facilitates the generation of genomic diversity among progeny, allowing adaptation to adverse changes in the ...
Some red algae (such as Bonnemaisonia [20] and Lemanea) and green algae (such as Prasiola) have vegetative meiosis, also called somatic meiosis, which is a rare phenomenon. [21] Vegetative meiosis can occur in haplodiplontic and also in diplontic life cycles. The gametophytes remain attached to and part of the sporophyte.
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
A few species of insects and crustaceans can reproduce by parthenogenesis, especially if conditions favor a "population explosion". However, most arthropods rely on sexual reproduction, and parthenogenetic species often revert to sexual reproduction when conditions become less favorable. [30]
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