Summary
Genetic typing of short tandem repeat (STR) loci may require electrophoretic separation techniques which, depending on the locus, can resolve alleles differing in size by only 2, 3 or 4 base pairs (bps). Many such loci can be separated by horizontal, discontinuous polyacrylamide gel electrophoresis (hd-PAGE). However, some loci present particular separation challenges. A composite (or step) gel system consisting of 2 zones, anodal and cathodal, which differ by pore size and ionic strength, has been developed to augment resolution of DNA fragments without a need for additional electrophoretic equipment. Depending on pore size, as well as ionic strength, initial migration can be increased or decreased to effect resolution. When compared with hd-PAGE, this composite gel electrophoretic system can result in enhanced resolution of PCR amplified STR alleles.
Zusammenfassung
Die genetische Typisierung von Short Tandem Repeat (STR)-Loci erfordert elektrophoretische Trenntechniken, welche in Abhängigkeit vom Locus Allele unterscheiden können, welche sich in der Größe durch nur 2, 3 oder 4 Basenpaare unterscheiden. Zahlreiche solcher Loci können mit Hilfe der horizontalen, diskontinuierlichen Polyacrylamidgel-Elektrophorese (hd-PAGE) aufgetrennt werden. Einige Loci stellen jedoch eine besondere Herausforderung an die Trenntechnik. Ein zusammengesetztes (oder Schritt-)Gelsystem, welches aus zwei Zonen besteht - einer anodischen und einer kathodischen -, welche sich durch die Porengröße und Ionenstärke unterscheiden, wurde entwickelt, um die Auftrennung von DNA-Fragmenten zu verbessern, ohne daß eine zusätzliche elektrophoretische Ausstattung erforderlich ist. In Abhängigkeit von der Porengröße und von der Ionenstärke kann die anfängliche Wanderungsgeschwindigkeit verstärkt oder verlangsamt werden, mit Auswirkung auf die Auflösung. Im Vergleich zur hd-PAGE kann dieses zusammengesetzte gelelektrophoretische System zu einer gesteigerten Ruftrennung von PCR-amplifizierten STR-Allelen führen.
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This work was partially supported by a 1991 Scientific Committee of NATO grant awarded to J. A. Lorente
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Lorente, M., Lorente, J.A., Wilson, M.R. et al. Composite PAGE: An alternate method for increased separation of amplified short tandem repeat alleles. Int J Leg Med 106, 69–73 (1993). https://doi.org/10.1007/BF01225043
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DOI: https://doi.org/10.1007/BF01225043