Centro de Documentação da PJ
Analítico de Periódico
CD 344
The effect of insect excretions/secretions and decomposition fluid on DNA quantity and quality in human bloodstains [Recurso eletrónico] / Maggie Murphy …[et al.]
Journal of Forensic Sciences, Vol. 69, n. 6 (November 2024), p. 2082-2090
Ficheiro de 1,9 MB em formato PDF.
ENTOMOLOGIA FORENSE, ANÁLISE DE SANGUE, ADN
The larval excretions/secretions (ES) of blowflies contain proteolytic enzymes and bacteria that assist with tissue breakdown. Decomposition fluid (DF) contains organic and inorganic waste products from cell death. This study investigated if human DNA recovery from blood was impacted by exposure to ES and DF over time. Lucilia sericata ES were collected daily from 50 larvae, and all available DF was collected from two fetal piglets left to decompose for 2 weeks. Daily for 3–5 days, 28 ìL-30 ìL of ES, DF, or a 1:1 mixture of the fluids was added to 30 ìL of blood on cotton. Three bloodstains per treatment were sampled every 12 h up to 3 days and at 1 and 2 weeks after initial addition of fluid. No PCR inhibition was detected, but DNA degradation increased over time, primarily in samples exposed to ES and ES/DF mixtures. The amount of DNA recovered decreased over time, but generally more DNA was recovered from DF samples than other samples. Full profiles, or partial profiles suitable for routine database searching (14–39 alleles), were generated from all DF and ES samples and at least one mixture sample at all time-points. Partial profiles of between 1 and 13 alleles were obtained from all other mixture samples, except one mixture sample which generated no profile. These findings indicate bloodstain evidence recovered from maggot-infested and/or decomposing bodies may generate forensically useful DNA evidence and should be analyzed as quickly as possible after collection or stored appropriately to prevent further degradation.
