The number of STR markers necessary to resolve relationships in deficiency paternity cases

Genotype probabilities of pairs of individuals for X‐chromosome markers

“…Considering real markers, we selected for analysis the following four STRs, which are located in different linkage groups 23 and cover a wide range of allele number and heterozygosities (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) distributions were obtained from publications by Toni and coworkers 17 and Bini and coworkers. 24 Because development and validation of X-STR are still growing, these markers have been chosen only as a useful example, and they could not be the best X-STR to use; for example, a recently developed commercial kit (Biotype AG, Dresden, Germany) includes the four loci DXS8378, DXS7132, HPRTB, and DXS7423.…”

“…11 When only duos must be evaluated, the power of a given set of genetic markers to provide evidence of a pretended true relationship is greatly reduced 12 and it is likely that the set of markers available in commercial kits does not provide statistical power to resolve relationships with sufficient confidence. 13,14 The use of X-chromosome markers (X-STRs) in forensic practice has played a minor role so far, probably because of its peculiar genetic transmission. It is often assumed that X-STRs are only suitable for paternity testing when the disputed child is a girl, so that their potential use in forensic casework studies is reduced by a half.…”

“…Other examples involving testing relationships between pairs of individuals include the attribution to missing individuals of one or more body remains, 6 identification of the victims of mass disasters, 7 validation of large databases of individual genetic profiles, 8,9 reconstruction of genealogies when there are no civic records, 10 or inferring relationships in ancient cemeteries 11 . When only duos must be evaluated, the power of a given set of genetic markers to provide evidence of a pretended true relationship is greatly reduced 12 and it is likely that the set of markers available in commercial kits does not provide statistical power to resolve relationships with sufficient confidence 13,14 …”