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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.
An oocyte (/ ˈ oʊ ə s aɪ t /, oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell (PGC), which then undergoes mitosis ...
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]
Oocyte quality is also a main contributor to overall embryo quality since it is the DNA of the oocyte that is mainly involved in the first 3 days of embryo growth following fertilization. A major source of genetic abnormalities are balanced translocations (Figure 1). [9]
Polar body biopsy is the sampling of a polar body of an oocyte.It was first applied clinically in humans in 1987 after extensive animal studies. [1] A polar body is a small haploid cell that is formed concomitantly as an egg cell during oogenesis, but which generally does not have the ability to be fertilized.
At birth, meiosis arrests at the diplotene phase of prophase I. [7] Oocytes will remain in this state until the time of puberty. At the time of ovulation a surge of LH initiates the resumption of meiosis and oocytes enter the second cycle, which is known as oocyte maturation. Meiosis is then arrested again during metaphase 2 until fertilisation ...
Oocytes are carefully denudated from the cumulus cells, as these cells can be a source of contamination during the PGD if PCR-based technology is used. In the majority of the reported cycles, intracytoplasmic sperm injection (ICSI) is used instead of IVF. The main reasons are to prevent contamination with residual sperm adhered to the zona ...
The secondary oocyte continues the second stage of meiosis (meiosis II), and the daughter cells are one ootid and one polar body. 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.