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Oocyte abnormalities can be caused by a variety of genetic factors affecting different stages in meiosis. [1] Moreover, ageing is associated with oocyte abnormalities since higher maternal age is associated with oocytes with a reduced gene expression of spindle assembly checkpoints which are important in maintaining stability in the genome.
The arrest of ooctyes at the four genome copy stage appears to provide the informational redundancy needed to repair damage in the DNA of the germline. [26] The repair process used likely involves homologous recombinational repair. [26] [27] [28] Prophase arrested oocytes have a high capability for efficient repair of DNA damages. [27]
The dictyate appears to be an adaptation for efficiently removing damages in germ line DNA by homologous recombinational repair. [5] Prophase arrested oocytes have a high capability for efficient repair of DNA damages. [5] DNA repair capability appears to be a key quality control mechanism in the female germ line and a critical determinant of ...
Other symptoms include vomiting, muscle aches, dizziness or a fever that comes and goes. After this primary infection, the disease can go dormant, but the symptoms may return regularly and other conditions like jaundice can develop because Plasmodium vivax establishes itself in the liver.
Ovum quality is the measure of the ability of an oocyte (the female gamete) to achieve successful fertilisation.The quality is determined by the maturity of the oocyte and the cells that it comprises, which are susceptible to various factors which impact quality and thus reproductive success. [1]
BRCA1 and ATM proteins are employed in repair of DNA double-strand break during meiosis. These proteins appear to have a critical role in resisting ovarian aging. [25] However, homologous recombinational repair of DNA double-strand breaks mediated by BRCA1 and ATM weakens with age in oocytes of humans and other species. [25]
In mouse oocytes, DNA damage induces meiotic prophase I arrest that is mediated by the spindle assembly checkpoint. [57] Arrested oocytes do not enter the subsequent stage, anaphase I. DNA double strand breaks, UVB and ionizing radiation induced DNA damage cause an effective block to anaphase promoting complex activity. [57]
Secondary oocytes are the immature ovum shortly after ovulation, to fertilization, where it turns into an ootid. Thus, the time as a secondary oocyte is measured in days. Thus, the time as a secondary oocyte is measured in days.