Efficient reidentification of chromosome slides from human metaphase spreads via microsatellite polymerase chain reaction.

In order to exclude inadvertent mixing of slides carrying metaphase spreads, chromosomal DNA was re-extracted several months after routine slide preparation (hypotonic treatment, spreading, fixation, staining, embedding and microscopic inspection) in different laboratories. The DNA yield was largely dependent on the number of cells originally fixed and the batch of the embedding material. Average fragment sizes ranged below 200 nucleotides. The polymerase chain reaction systems for DNA amplification included several polymorphic microsatellite loci specifically selected for short amplification products. Reidentification with a high probability for identity was possible by comparison with microsatellite alleles obtained from the peripheral blood of the individuals investigated. Possible applications, the differentiation potential and the limitations of the methodology are discussed.