Quality and quantity of extracted deoxyribonucleic Acid (DNA) from preserved soft tissues of putrefied unidentifiable human corpse

Abstract

Context: The appropriate collection and preservation of soft tissues from putrefied unidentifiable human corpse for the purpose of identification using DNA profiling technique is critically important especially in developing countries like India having different levels of health-care set ups with largely varying facilities and varying climatic conditions.

Aims: The present study was carried out, mainly focusing on quality and quantity of extracted DNA from the soft tissues of putrefied unidentifiable human corpse stored upto 4 weeks at 4°C and at -80°C for DNA analysis.

Materials and methods: The present study was conducted on 16 different putrefied unidentifiable human corpses after getting approval from institutional ethical committee. Around 2 g of four different tissues (brain, kidney, heart and muscle) were collected and preserved for one month followed by DNA extraction using the organic method, the quality and quantity of high molecular weight-DNA was estimated using the spectrophotometer and gel electrophoresis. Further, the amplification polymerase chain reaction (PCR) was also performed (AmpFLSTR(®) Indentifiler™ PCR Amplification kit for multiple loci, of Applied Biosystems, Lab India) and was checked using continuous PAGE.

Results: The yield of DNA was significantly higher at -80°C for all the four tissues collected and was best for brain followed by heart, kidney and worst for muscles in all cases.

Conclusions: It is suggested that the brain tissue preserved at -80°C is the best among soft issues for DNA extraction. Refrigeration or deep freezing facility should be available at all the centers.

Keywords: DNA-profiling; putrefaction; soft tissues..

Graph 1

Decrease in deoxyribonucleic acid yield with change in temperature from −80°C to 4°C, sample 1 = brain, sample 2 = heart, sample 3 = kidney, sample 4 = muscle

Figure 1

Extracted deoxyribonucleic acid on agarose gel electrophoresis. 1 = brain, 2 = heart, 3 = kidney, 4 = muscle

Figure 2

12% PAGE (continuous) (Lane L = uncut ladder, Lane 1 = brain, Lane 2 = heart, Lane 3 = kidney and Lane 4 = muscle, Lane N = negative control)

Figure 3

Electropherogram of brain tissue stored at −80°C showing amplification at all 16 loci in the form of sharp allele peaks