Critical Family Members Research Articles

Potentials and limits of pairwise kinship analysis using autosomal short tandem repeat loci

At least in principle, most instances of complex kinship testing can be reduced to pairwise kinship cases involving two critical family members that either link or separate presumed sub-branches of a family. In the European population, the 34 short tandem repeats (STRs) currently used in forensic genetics are sufficiently powerful to allow assessment of disputed first and second but not lower degrees of pairwise blood relatedness. We provide estimates of the means and variances of marker-specific log-likelihood ratios, using large-sample approximation and assuming different scenarios of pairwise kinship analysis. These estimates allow power calculations to be performed for any combination of the available STRs. Since some of the markers considered are physically linked, chromosome-wide likelihood calculations in kinship cases other than parent-child duos (and trios) have to take the reduced rates of meiotic inter-marker recombination into account. We show by simulation that this requirement may be ignored when discriminating distant hypotheses about kinship, but that linkage may play an important role in the biostatistical analysis of more intricate cases.

Single-blind study of dystrophin staining in carriers of Duchenne muscular dystrophy.

A single-blind study of dystrophin staining in skeletal muscle was performed in 13 biopsies from carriers of Duchenne Muscular Dystrophy (DMD) and controls. The results indicate that immunohistochemical analysis of dystrophin staining is a valuable diagnostic test for DMD carriers when DNA for testing is unavailable from critical family members or is uninformative, when creatine kinase (CK) values are conflicting or when CK values must be used in isolation.

Application of DNA Fingerprinting to Parentage and Extended Family Relationship Testing

For the purpose of applying DNA fingerprinting to parentage or other extended blood relationship testing, we have developed a general system for estimating blood relationship between a set of individuals. This system can be used for any blood relationship testing, even if critical family members are unavailable. A general formula for calculating the probability of such relationships based on Bayes' theorem has been devised and the ability of DNA fingerprinting produced by Jeffrey's polycore probe to determine the relationships has been evaluated.