Analysis of Blood Spot in the Crime Scene in Relation to the Environmental Parameters

Abstract

This study was designed to evaluate the analysis of blood samples in crime scene under different environmental
conditions. Samples are divided into four main groups depending on the source of bloodspot: Soil, Stone,
Ceramic, and Water sample. Each group consisted of two sub-groups depending on weather temperature in
Iraq in winter and summer: 8 °C groups and 45 °C groups. Each group consisted of 32 samples. Samples
were collected after different time (0, 2, 6, and 24) hours.
The results of the current study showed variation in the ability to extract DNA depending on the surface type.
In addition, DNA can be extracted from bloodstains on soil, gravel, ceramics, and water when extracted
immediately after exposure to the surface. The difference in the ability to extract DNA from bloodstains
on different surfaces after two hours at 8 °C temperature, where the success rate of extraction is (25, 7.5,
100, and 100%) for soil, stone, ceramics, and water samples Respectively. The ability rate to extract DNA
after two hours at 45 °C temperature, where (25, 7.5, 87.5, and 100%) for soil, gravel, ceramics, and water
samples respectively. The ability rate to extract DNA after six hours at 8 °C temperature, where (0, 12.5,
37.5, and 100%) for soil, gravel, ceramics, and water samples respectively, while it was (0, 12.5, 25, and
100%) for six hours samples at 8 °C temperature. After 24 hours, only water samples showed the ability to
extract DNA from all samples, while no DNA was obtained from the rest of the samples.
PCR amplification of the FIF2AK3 gene showed products when the DNA extracted immediately after their
adhesion to the surface of the soil while showing no products for other age groups. Also, the PCR products
can be obtained when DNA isolate immediately after exposure to the stone surface, whereas the rate PCR
amplification products of DNA isolated after two hours was (37.5%) for both groups 8 °C and 45 °C., while
other age groups showing not products.
The agarose gel electrophoresis of PCR products showed the possibility of FIF2AK3 gene amplification
when blood samples were taken immediately after exposure to the surface, whereas the ability to obtain
amplification products was (100 and 87.5%) for groups 8 °C and 45 °C respectively. No products were
obtained after 6 and 24 hours. In water samples, all isolated DNA gave the product.