Karyotyping of human oocytes by chromosomal analysis of the second polar bodies

This paper describes a method for obtaining metaphase chromosomes from huma n second polar bodies. The second polar body nucleus was injected into the cytoplasm of an enucleated oocyte, which is activated shortly after injecti on. When the polar body nucleus is transformed into a haploid pronucleus, t reatment with okadaic acid was used to induce premature chromosome condensa tion, A total of 25 analysable chromosome plates were obtained from 38 pola r bodies karyotyped using this technique. Whole chromosome painting was use d to detect second polar bodies land respectively, oocytes) with unbalanced translocations. In combination with the first polar body analysis, this te chnique may be useful in preimplantation genetic diagnosis for patients car rying maternal translocations.