PGD: Polar body biopsy with three color FISH
In this example, a patient has undergone IVF with PGD to determine if there are abnormalities in the number of chromosomes. The 1st polar body pictured (PB1) is normal for the two chromosomes being tested. Each chromosome is represented by a different color. Each chromosome is represented as “double chromatid” chromosome. That is why there are two dots for each chromosome. The 2nd polar body (PB2) has only a single dot for each chromosome representing a “single chromatid” chromosome. This is the normal state for a 2nd polar body. We can state that the embryo that these polar bodies came from has the correct number of chromosomes for each of the three chromosomes that are tested here.