Polar body

Polar body, also called polar bodies or towards the body, are in the course of maturation or reduction division (meiosis ) formed and adhere to the (future) egg. In many species, the polar body lay the animal pole of the egg firmly, but not so in humans.

They are relatively low in the cytoplasm and have a haploid (simple) set of chromosomes and are degraded in the rule ( degenerate ).

In humans ( as in all vertebrates ), there are two polar bodies. The first is formed during meiosis in the first meiotic division of the primary Oozyts and has a haploid set of chromosomes with 46 chromatids. At the same time, the secondary oocyte is formed. In the second meiotic division, the secondary oocyte is divided into a further polar body and the oocyte, each containing a haploid set of chromosomes with 23 chromatids. Also the polar body, which was created at the first meiotic division, division; There are thus at the end of three polar bodies present.

The polar body can be used as part of the polar body, a possible type of preconception or preimplantation genetic diagnosis for the examination of the female germ line genetic peculiarities before the implantation of in vitro fertilized ( " in vitro fertilization " ) embryos.