Evaluation of the forensic efficiency of ChrX markers the population under investigation

This function provides information on the power of forensic analysis using the respective markers. Formulae are listed in the table. Two of the parameters listed, namely the polymorphism information content (PIC) [1] and the expected heterozygosity (Het) [2], have been devised for more general purposes and are valid for both AS and ChrX markers. The mean exclusion chance (MECKRÜ) was introduced by Krueger et al. [3] for AS markers typed in trios involving mother, child and putative father (formula I). This parameter is not suitable for ChrX markers except for deficiency cases in which the paternal grandmother is investigated instead of the alleged father. Kishida et al. [4] devised a MECKIS for ChrX markers which covers trios including a daughter (formula II). If MECKRÜ is compared to MECKIS, the latter is considerably larger. This highlights the fact that in trios involving a daughter, ChrX markers are more efficient than AS markers. Finally, Desmarais et al. [5] introduced formulae for the mean exclusion chance of ChrX markers in trios involving daughters (formula III) and in father/daughter duos lacking maternal genotype information (formula IV). MEC(III) is equivalent to MEC(II) whilst MEC(IV) is also appropriate for maternity testing of mother/son duos. PDM and PD Fare parameters suitable to evaluate the power of the markers for forensic identification purposes in males and females, respectively.

1. Botstein D, White RI, Skolnick M, Davis RW (1980) Construction of a genetic linkage map in man using restriction fragment length polymorphisms. Am J Hum Genet 32:314–331
   
2. Nei M, Roychoudhury AK (1974) Sampling variances of heterozygosity and genetic distance. Genetics 76:379–390
3. Krüger J, Fuhrmann W, Lichte KH, Steffens C (1968) Zur Verwendung der sauren Erythrocytenphosphatase bei der Vaterschaftsbegutachtung.Dtsch Z Gerichtl Med 64:127–146
4. Kishida T, Wang W, Fukuda M, Tamaki Y (1997) Duplex PCR of the Y-27H39 and HPRT loci with reference to Japanese population data on the HPRT locus. Nippon Hoigaku Zasshi 51: 67–69 18.
5. Desmarais D, Zhong Y, Chakraborty R, Perreault C, Busque L (1998) Development of a highly polymorphic STR marker for identity testing purposes at the human androgen receptor gene(HUMARA). J Forensic Sci 43:1046–1049