polar bodies are produced during the formation of an egg cell during oogenesis.
polar bodies are produced during the formation of an egg cell during oogenesis.
polar bodies are produced during the formation of?
an egg cell during oogenesis
a "polar body biospy" is the sampling of a polar body, which 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. compared to a blastocyst biopsy, a polar body biopsy can potentially be of lower costs, less harmful side-effects, and more sensitive in detecting abnormalities. the main advantage of the use of polar bodies in pgd is that they are not necessary for successful fertilisation or normal embryonic development, thus ensuring no deleterious effect for the embryo. one of the disadvantages of pb biopsy is that it only provides information about the maternal contribution to the embryo, which is why cases of maternally inherited autosomal dominant and x-linked disorders that are exclusively maternally transmitted can be diagnosed, and autosomal recessive disorders can only partially be diagnosed. another drawback is the increased risk of diagnostic error, for instance due to the degradation of the genetic material or events of recombination that lead to heterozygous first polar bodies.
preimplantation genetic diagnosis
the main advantage of the use of polar bodies in pgd is that they are not necessary for successful fertilisation or normal embryonic development, thus ensuring no deleterious effect for the embryo. one of the disadvantages of pb biopsy is that it only provides information about the maternal contribution to the embryo, which is why cases of autosomal dominant and x-linked disorders that are maternally transmitted can be diagnosed, and autosomal recessive disorders can only partially be diagnosed. another drawback is the increased risk of diagnostic error, for instance due to the degradation of the genetic material or events of recombination that lead to heterozygous first polar bodies. it is generally agreed that it is best to analyse both polar bodies in order to minimize the risk of misdiagnosis. this can be achieved by sequential biopsy, necessary if monogenic diseases are diagnosed, to be able to differentiate the first from the second polar body, or simultaneous biopsy if fish is to be performed.
polar body biopsy