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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.
Offspring have two sex chromosomes: an offspring with two X chromosomes (XX) will develop female characteristics, and an offspring with an X and a Y chromosome (XY) will develop male characteristics, except in various exceptions such as individuals with Swyer syndrome, that have XY chromosomes and a female phenotype, and de la Chapelle Syndrome ...
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 ...
The human Y-chromosome has had about 5 strata since the origin of the X and Y chromosomes about 300 Mya from a pair of autosomes. Each stratum was formed when a pseudoautosomal region (PAR) of the Y chromosome is inverted, stopping it from recombination with the X chromosome. Over time, each inverted region decays, possibly due to Muller's ratchet.
This is an accepted version of this page This is the latest accepted revision, reviewed on 11 February 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 ...
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 ...
In meiosis, non-sister homologous chromosomes pair with each other so that recombination characteristically occurs between non-sister homologues. In both meiotic and mitotic cells, recombination between homologous chromosomes is a common mechanism used in DNA repair .
Thus, those cells in which X-Y recombination does not occur will fail to complete meiosis. Structural and/or genetic dissimilarity (due to hybridization or mutation) between the pseudoautosomal regions of the X and Y chromosomes can disrupt pairing and recombination, and consequently cause male infertility.