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Comparison of two molecular weight markers used in DNA-profiling
1Institute of Forensic Genetics, University of Copenhagen, Denmark.
International Journal of Legal Medicine
|January 1, 1992
Summary
The Gibco BRL marker offers more reliable DNA fragment size calculations than the Amersham marker in DNA profiling. This improves accuracy in forensic casework by reducing variability in fragment length determination.
Area of Science:
- Forensic Genetics
- Molecular Biology
- Biotechnology
Background:
- DNA profiling is crucial for human identification.
- Accurate DNA fragment size determination is essential for reliable profiling.
- Different DNA size markers can impact fragment length calculations.
Purpose of the Study:
- To compare the accuracy and reliability of two DNA size markers (Amersham SJ5000 and Gibco BRL 4401SA) for DNA profiling.
- To assess the impact of marker choice on fragment length calculations.
- To evaluate the implications for forensic casework.
Main Methods:
- DNA profiling using restriction enzyme HinfI on human blood DNA.
- Analysis of DNA fragments with single locus probes (MS1, MS31, MS43a, YNH24).
- Size determination of DNA fragments (1.4–22 kb) using Amersham SJ5000 and Gibco BRL 4401SA markers.
Main Results:
- The Gibco BRL marker demonstrated a significantly lower standard deviation in duplicate determinations compared to the Amersham marker.
- Fragment length calculations differed significantly between the two markers, particularly for fragments > 8 kb.
- Amersham marker resulted in 3–8% higher fragment lengths (1.0–1.8 mm migration difference), an effect amplified by ethidium bromide.
Conclusions:
- The Gibco BRL marker provides more precise and reproducible DNA fragment sizing than the Amersham marker.
- Switching to the Gibco BRL marker can enhance the accuracy of DNA profiling in forensic applications.
- Standardization with a more reliable marker is recommended for practical casework.
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