Two examples of null alleles at the D19S433 locus due to the same 4 bp deletion in the presumptive primer binding site of the AmpFlSTR Identifiler kit

Two cases of allelic loss at the D19S433 locus after multiplex PCR with the AmpFlSTR Identifiler kit (Applied Biosystems) are described. In both cases the failure of PCR resulted in genetic inconsistencies due to opposite homozygosity. After singleplex PCR with published primers additional alleles were observed and Mendelian inheritance was restored. These PCR products were sequenced and in both cases the same 4 bp deletion near the 3′ end of the repeat region was detected in two alleles of different length. The frequency of these null alleles (two events in 1026 allelic transfers) amounts to 0.0019 (95% confidence limits: 0.0002-0.0070).     

Interrogation of short tandem repeats using fluorescent probes and melting curve analysis: A step towards rapid DNA identity screening

Current forensic DNA profiling methods rely on the analysis of samples at specialised laboratories with an average turnaround time of several days. The ability to rapidly determine a partial profile of short tandem repeats at the point-of-arrest would be of great benefit to police forces around the world, for example enabling a suspect to be rapidly included or excluded from an investigation. We have developed a homogeneous PCR method for the interrogation of STR loci utilising fluorescent oligonucleotide probes and melting curve analysis. Alleles of the D18S51, TH01 and D8S1179 loci were differentiated and identified on the basis of target length and probe melting temperature. Assay performance was evaluated by comparing melting peak data with the AmpFlSTR^® SGM Plus^® system. The method is compatible with direct analysis of unpurified buccal swab samples, enabling a partial STR profile to be generated within 1 h.     

The toxicological examination of the victims of the British Air Tours Boeing 737 accident at Manchester in 1985

The results of toxicological analyses of the body fluids of the victims from the accident involving the British Air Tours Boeing 737 in August 1985 are presented for carboxyhemoglobin, cyanide, and volatiles. All the victims except one had raised concentrations of carbon monoxide. All the victims had raised concentrations of cyanide. All the victims showed the presence of volatile substances in the blood. Autopsies revealed that all the victims had carbon particles in the trachea and bronchi. Thus, all the victims must have inhaled fire products in the burning aircraft cabin. Six victims had concentrations of carbon monoxide or cyanide in the blood that were neither fatal nor incapacitating; therefore, it is reasonable to suggest that these six victims survived for a comparatively short time and that there may have been other causes, in addition to toxic fumes, for their deaths. The other 48 victims must have survived long enough in the fire to accumulate incapacitating or fatal concentrations of carbon monoxide or cyanide or both. The effects of these substances found in the blood of each of the 48 victims must have combined to produce an insurmountable impediment to escape from the aircraft.     

A comparison of insanity defense standards on juror decision making

Following the Hinckley acquittal, 17 states and the federal government made changes to the insanity defense, including revising the standard, reassigning the burden of proof, and altering the standard of proof. Two studies were conducted to determine whether the specific insanity standard (including the assignment of burden of proof and standard of proof) employed had a significant effect on mock jurors' verdicts. Participants' comprehension of insanity defense instructions was measured and the factors jurors used to decide whether to find the defendant not guilty by reason of insanity (NGRI) were also assessed. Participants' comprehension of insanity defense standards was very low. When asked to identify the factors they considered important in determining whether to find a defendant NGRI, only three elements of insanity defense standards were identified as significant. The results may have important implications for policy decisions regarding the insanity defense.