Jenna Kausner
5/18/11
PBIO 427
DNA Profiling and Forensics Abstract
Can post-mortem blood be used for DNA profiling after peri-mortem blood transfusion?
A controversial issue in forensics is if blood transfusions can affect DNA profiling.
Many people assume that the STR profile generated will be from the transfused blood instead of
the deceased individual’s blood. Therefore, other biological samples such as plucked hair or
deep muscle are required for DNA profiling, which leads to a higher cost and more time to
process samples. However, the literature does not agree with this assumption, and previous
reports have demonstrated that blood transfusion has not affect on DNA profiling of blood from
either living or dead individuals. This paper presents a study on whether STR profiling of a dead
individual’s blood can be performed if the individual received large amounts of peri-mortem
blood transfusions. In addition, the affect of organ transplantation of DNA profiling was tested.
Five cases of individuals who received massive peri-mortem blood transfusions were
used to collect samples for DNA profiling. Blood was collected from the iliac vein and samples
were collected from psoas muscle tissue and plucked hear hairs. DNA extraction was carried out
using the QIAamp DNA Blood Mini Kit and QIAamp DNA Tissue Mini Kit. The plucked hairs
were washed twice with sterile water and then 70% ethanol. The hairs were then put in a tube
with lysis buffer and proteinase K and incubated for 24 hours at 37 ºC to undergo digestion.
Then, the DNA was purified using phenol/chloroform/isoamylalcohol and Microcon
concentration. DNA was extracted from a donated solution of leucocyte-depleted red blood cells
(RBCs). No DNA was detected using quantification or STR profiling for the packed red blood
cells. To test for the detectable levels of free DNA/cells required for detection in red blood cell
concentrates, human dermis fibroblasts were obtained from a cell culture from a donated breast
reduction surgical specimen and genomic DNA was purchased as a control. Serial dilutions of
the cells and genomic DNA were performed and added to the aliquots of RBC solution. It was
determined that a level of 1,000 cells or 10 ng free genomic DNA had to be added in order to be
detected to the RNC (RBC) concentrate. To obtain a full profile, 100 ng DNA had to be added.
From the five deceased individuals, DNA was extracted from hair, blood, and muscle and
DNA profiling was performed. The plucked hairs were used for a reference profile to compare
the post-transfusion materials to. In each of the five cases, the DNA profiles were the same for
the blood samples and plucked hair samples, except in the liver case which showed a mixture of
two DNA sources. Conclusively, large amounts of DNA or DNA-containing materials must be
present in order for DNA to be detected in the recipient’s blood and the study supports allowing
blood samples from recipients who have received major blood transfusions to be profiled. In
addition, blood may be collected from recipients of organ transplants, but further studies need to
be done in this area.
Reference:
Graham, E. A. M., Toskos, M. & Rutty G. N. (2007) Can post-mortem blood be used for DNA
profiling after peri-mortem blood transfusion? Int J Legal Med, 121: 18-23.