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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, the ...
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 ...
Meiosis undergoes two divisions resulting in four haploid daughter cells. Homologous chromosomes are separated in the first division of meiosis, such that each daughter cell has one copy of each chromosome. These chromosomes have already been replicated and have two sister chromatids which are then separated during the second division of ...
The mouse oocyte in the dictyate (prolonged diplotene) stage of meiosis actively repairs DNA damage, whereas DNA repair was not detected in the pre-dictyate (leptotene, zygotene and pachytene) stages of meiosis. [14] The long period of meiotic arrest at the four chromatid dictyate stage of meiosis may facilitate recombinational repair of DNA ...
In the first stage of sexual reproduction, meiosis, the number of chromosomes is reduced from a diploid number (2n) to a haploid number (n). During fertilisation, haploid gametes come together to form a diploid zygote, and the original number of chromosomes is restored.
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.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
Meiosis only occurs in cells of the sex organs, and serves the purpose of generating haploid gametes such as sperm, eggs, or spores, which are later fused during fertilization. The two meiotic divisions, known as Meiosis I and Meiosis II, may also include various genetic recombination events between homologous chromosomes. meiotic spindle