Search results
Results From The WOW.Com Content Network
This is an accepted version of this page This is the latest accepted revision, reviewed on 16 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 ...
As a result, double strand breaks in meiotic cells, unlike mitotic cells, do not typically lead to apoptosis, or cell death. [9] Homologous recombinational repair (HRR) of double-strand breaks occurs in mice during sequential stages of spermatogenesis but is most prominent in spermatocytes. [10]
Normal spermatogenesis, testis biopsy. High-power view of a seminiferous tubule with normal spermatogenesis. Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testicle. This process starts with the mitotic division of the stem cells located close to the basement membrane of ...
These are: (1) pairing of homologous chromosomes, (2) extensive recombination between homologs; (3) suppression of sister chromatid separation in the first meiotic division; and (4) avoiding chromosome replication during the second meiotic division.
The spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte. Spermatids are connected by cytoplasmic material and have superfluous cytoplasmic material around their nuclei.
During spermatogenesis, each meiotic division is symmetric such that each primary spermatocyte gives rise to 2 secondary spermatocytes after meiosis I, and eventually 4 spermatids after meiosis II. Meiosis II-nondisjunction may also result in aneuploidy syndromes, but only to a much smaller extent than do segregation failures in meiosis I. [6]
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 ...
The following are a few of the diseases that can occur and be present during the process. Polyspermy results from multiple sperm fertilizing an egg, leading to an offset number of chromosomes within the embryo. [34] Polyspermy, while physiologically possible in some species of vertebrates and invertebrates, is a lethal condition for the human ...