Full STR profile of a 67-year-old bone found in a fresh water lake

DNA extraction from and DNA typing of fresh water-exposed aged bone specimens poses a challenging task and is not very well examined. This study presents a new method to extract typable DNA from such problematic bone specimens. The procedure comprises low-heat drilling and cryogrinding, mild lysis conditions, and silica-column-based DNA cleaning. DNA quantity is assessed by quantitative PCR prior to short tandem repeat (STR) amplification. The procedure was employed with a 67-year-old tibia bone fragment recovered from a fresh water lake and succeeded to produce a full STR profile using the MPX-SP1 and MPX-SP2 mini-STR kits and a partial profile with 12 successfully amplified STRs using the Identifiler STR kit. The new method for the extraction of DNA from aged fresh water-exposed bone specimens presented herein was successfully applied to prepare DNA of sufficient quality and quantity to generate a full STR profile.     

Significant association of TH01 allele 9.3 and SIDS

Sudden infant death syndrome (SIDS) constitutes a considerable percentage of infant death of unknown etiology. Individual catecholamine response variation is suspected to play a role in SIDS. TH01 is a tetrameric short tandem repeat marker in the tyrosine hydroxylase gene, which regulates gene expression and catecholamine production with allele 9.3 exerting a particularly strong effect on noradrenaline production. We investigated in an age-controlled study the TH01 allele frequencies in 127 cases of SIDS and 406 control cases to assess whether in SIDS cases a distinct TH01 allele distribution could be determined as has been reported by a previous study. We found that genotypes containing one or two 9.3 alleles were significantly more frequent in SIDS patients (58.2%) than in control subjects (48.4%, p=0.038), whereas all other alleles were more frequent in the control subjects. Our findings support the notion that there exists a significant association between TH01 gene configuration and SIDS.     

No association of IL-10 promoter SNP −592 and −1082 and SIDS

Sudden infant death syndrome (SIDS) constitutes a considerable percentage of infant death of unknown etiology. The genetically controlled pathway of cytokine mediated response to inflammation is presumed to play a role in SIDS. The A allele of SNP ?592 of the promoter region of the anti-inflammatory cytokine IL-10 has been suggested to be associated with SIDS. Herein we investigated whether we could confirm this finding by SNP genotyping a series of 123 cases of SIDS and 406 control cases. We did not find a correlation between the A allele or an A allele containing genotype of IL-10 promoter SNP ?592 and SIDS which is in contrast to previous studies. Also, in concordance with previous work, no association of the A allele or A allele containing genotypes of IL-10 promoter SNP ?1082 and SIDS was found.     

Persistence of Biological Traces at Inside Parts of a Firearm from a Case of Multiple Familial Homicide

Backspatter from wounds caused by contact shots against a biological target had before been shown to be propelled into firearms' barrels where they can persist and be retrieved from as relevant forensic evidence. Herein, that insight was applied to the investigation of a case of multiple familial homicide with a firearm. Samples of backspatter were collected from the firearm using DNA‐free swabs. DNA was extracted from the swabs, and 16 STR systems were PCR‐amplified to generate DNA profiles of all victims shot by the firearm. The quality of the resulting DNA profiles was sufficient to exclude the perpetrator as donor and to differentiate the three closely related victims thereby proving that all three victims had been shot by the same firearm from very close or contact distance. A key insight gained from this case was that not only a firearms' barrel inside but other inner surfaces may be charged with profilable DNA.     

Assessment of STR Typing Success Rate in Soft Tissues from Putrefied Bodies Based on a Quantitative Grading System for Putrefaction

To date, there is no systematic investigation of the association of short tandem repeat (STR) typing success rate in soft tissues with different signs of putrefaction. Herein, putrefaction was rated using a newly developed 19‐parameter system in soft tissues from a collective of 68 decaying bodies, and DNA yield was determined in 408 samples. DNA integrity was rated using a self‐devised pentaplex PCR generating an “integrity score” (S_i). STR typing success rate was then assessed for selected cases. DNA yield and S_i differed significantly between tissues with kidney on average exhibiting the highest S_i values. Statistical analysis revealed that nine parameters were significantly and positively correlated with S_i. The observed values for each of these nine parameters were summed up to generate a putrefaction score (S_p) for each sample. Our results show that STR typing success rate can be predicted based on S_p before expensive multiplex STR profiling is performed.