Miklós Kásler - Zoltán Szentirmay (szerk.): Identifying the Árpád Dynasty Skeletons Interred in the Matthias Church. Applying data from historical, archaeological, anthropological, radiological, morphological, radiocarbon dating and genetic research (Budapest, 2021)

CHAPTER SEVEN – Genetic investigations

Peaks beyond normal allele lengths and the triple-peak pattern (three-banded pattern )

In the examination of allele lengths, a new allele may randomly appear next to one of the real A-STR allele pairs. This causes a problem for evaluation. The peaks can be the same, longer, or shorter than the corresponding consensus allele peaks. This phenomenon can be recognized if the examination is repeated with a different A-STR detection kit and a different result is obtained. The three-banded pattern that can be observed during individual marker localizations is not the artifact of the detection process, but rather that of the individual samples which can be reproduced. This can be caused by the presence of an extra chromosome or primer point mutations, or a bad quality DNA template (Crouse et

al.

1999). Up until August 4, 2016, a total of 389 three-banded patterns had been published. For example, 9 such peaks were registered at D2S1338,11 such peaks at D3S1358, 20 such peaks at D7S820, and 12 such peaks at D19S433, and this occurred with the same markers in our cases as well. The list of allele microvariations is frequently refreshed and can be found at the STRbase website: http://www.cstl.nist.gov/biotech/strbase/var_tab.htm.

“Stutter” artifacts

The electropherogram containing the STR data may show peaks, usually smaller ones, which are usually one repeat shorter or longer than a real PCR product. In the case of a microsatellite unit composed of several bases, the stutter artifact at one repeating unit can be longer or shorter than a real PCR peak. According to the model of the 124