By DNA analysis can you solve a crime , let's know how from forensic point of view

1. By Hebatullah Hassan Abass Rozza
Facuity of medicine , Alexandria , Egypt
DNA analysis in the
crime scene

2. Medico legal importance
of DNA
For
identification
of a victim
For
identification of
the assailant

3. Samples used or DNA analysis :
Any biological sample can be
used for DNA analysis ( blood,
saliva ,buccal swab,semen ,
vaginal swab ,sken, bone ,teeth
,,…)

4. DNA
fingerprinting
Never to find two
individuals have the
same sequence of
DNA

5. Kinship analysis
Autosomal STR
markers are the most
discriminating and are
used routinely in the
forensic science
service .
Short tandem
repeats (STRs) are
repeated
segments of DNA
( non coding
region)

6. Kinship analysis
Family
relation ship
testing
Matching and
identification
in the
forensic

7. Kinship analysis
one STR allele comes
from the mother and
the other STR allele
comes from the father.(
we detect 16 genetic
markers)

8. Steps for DNA processing
1-DNA extraction
1- cell lysis
2- protein
denaturation
3- separation of DNA
as a double stranded
DNA molecule

9. Steps for DNA processing
2- polymerase chain
reaction
As there is traces of
DNA , IT must be
amplified by PCR .
By repeated cycles of
denaturation , annealing
and extension.

10. 3- he scientist will treat
DNA with restriction
enzymes .
-This will produce
different sized fragments
which are known as
restriction fragment
length polymorphisms
(RFLPs).
-4-These fragments can
then be observed doing
an experiment called gel
electrophoresis which
separates DNA based on
fragment sizes.