Amplification of a beta-haemoglobin sequence in individual human oocytes and polar bodies.

A 680 base-pair sequence of the human beta-haemoglobin gene was reproducibly amplified in individual unfertilised human oocytes and in first polar bodies isolated from them. Specificity and sensitivity of amplification were achieved by two sequential reactions with two sets of primers, amplifying first a 725 base-pair sequence and secondly a 680 base-pair sequence from within the first amplified fragment. A restriction enzyme digest of the DNA amplified from a single oocyte with the endonuclease Dde I confirmed the identity of the amplified beta-haemoglobin fragment; this technique provides a diagnostic test for the genetic defect responsible for sickle cell anaemia. Analysis of the DNA from the first polar body may enable detection of such defects in unfertilised eggs from carrier women. Selection of eggs without the defect for fertilisation may therefore obviate the need for diagnostic procedures on embryos.