Microsatellite Stability in STR Analysis Aspergillus fumigatus Depends on Number of Repeat Units
Theun de Groot1, Jacques F Meis1,2,3
1Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital (CWZ), Nijmegen, Netherlands.
Abstract:
More than a decade ago a short tandem repeat-based typing method was developed for the fungus Aspergillus fumigatus. This STRAf assay is based on the analysis of nine short tandem repeat markers. Interpretation of this STRAf assay is complicated when there are only one or two differences in tandem repeat markers between isolates, as the stability of these markers is unknown. To determine the stability of these nine markers, a STRAf assay was performed on 73-100 successive generations of five clonally expanded A. fumigatus isolates. In a total of 473 generations we found five times an increase of one tandem repeat unit. Three changes were found in the trinucleotide repeat marker STRAf 3A, while the other two were found in the trinucleotide repeat marker STRAf 3C. The di- or tetranucleotide repeats were not altered. The altered STRAf markers 3A and 3C demonstrated the highest number of repeat units (≥50) as compared to the other markers (≤26). Altogether, we demonstrated that 7 of 9 STRAf markers remain stable for 473 generations and that the frequency of alterations in tandem repeats is positively correlated with the number of repeats. The potential low level instability of STRAf markers 3A and 3C should be taken into account when interpreting STRAf data during an outbreak.
Related Concept Videos
RNA Stability
Measurement: Derived Units
Nuclear Stability
To hold positively charged protons together...
Measurement: Standard Units
Stability
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
mRNA Stability and Gene Expression
Cis-acting Elements involved in mRNA stability


