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Factor B (BF) subtyping by isoelectric focusing: methods, nomenclatures, genetics and forensic application
1Institute of Forensic Medicine, Humboldt University, Berlin, German Democratic Republic.
Electrophoresis
|August 1, 1988
Summary
Factor B (BF) typing using isoelectric focusing identifies common BF F subtypes, enhancing paternity testing accuracy. This method improves exclusion rates and shows potential for bloodstain analysis.
Area of Science:
- Biochemistry
- Forensic Genetics
Background:
- Traditional agarose gel electrophoresis is standard for Factor B (BF) typing.
- The existence of BF F subtypes has been confirmed across diverse populations.
Purpose of the Study:
- To explore the utility of isoelectric focusing for BF typing, including common BF F subtypes.
- To clarify nomenclature discrepancies and identify less frequent BF variants.
- To assess the BF system's effectiveness in paternity testing and bloodstain analysis.
Main Methods:
- Isoelectric focusing (IEF) for BF F subtyping.
- Comparison with traditional agarose gel electrophoresis.
- Review of family, mother/child, and molecular-genetic studies.
Main Results:
- Isoelectric focusing extends BF typing with two common BF F subtypes.
- Nomenclature for subtypes FA/FB (Geserick) and Fb/Fa (Teng) may be reconciled.
- Paternity exclusion chance increases from ~14% (agarose) to ~16% (IEF) in Caucasians.
- Preliminary data suggests BF typing is feasible for bloodstains up to two weeks old.
Conclusions:
- Isoelectric focusing provides a more detailed BF typing system, including BF F subtypes.
- BF typing, especially with IEF, offers improved accuracy in paternity testing.
- Further investigation is warranted for resolving less common variants and validating bloodstain analysis applications.
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