الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 136 |  |  |
| | | from | 136 | | |
Abstract
Y-chromosome testing played an important role in forensic DNA
testing by answering some interesting historical questions like historical
human migration patterns through male lineages. STR markers on the Y
chromosome (Y-STRs) importance clearly observed in that they have
qualities that are distinct from autosomal markers and are useful for
human identification. DNA regions of Y chromosome with repeat units of
2-6 bp in length are called microsatellites or Y chromosome short tandem
repeats (Y-STRs) are very effective for human identification purposes.
DNA direct polymerase chain reaction (PCR) amplification is a
sample processing method in which an evidence or substrate punch is
added directly to the PCR without prior extraction. This resulted in an
improvement in the results of the genetic profiling data for these samples.
Direct PCR reduces loss of DNA because it does not involve sample
transfer or sample purification. This increases the sensitivity of PCR,
highlighting its benefit for latent DNA samples. The present study was
carried out to save the cost and time required for obtaining DNA profile
of Y chromosome through application of direct PCR method. Direct PCR
method also has the ability to give high quality of DNA profile and less
cross contamination.
When applying the direct PCR method to hair samples that were
taken from people who do not normally use any chemicals or hair waxes,
positive results were obtained more than the same samples that were
exposed in the routine extraction method. There was also a preference for
direct PCR method when used on one hair sample rather than three hairs
in contrast to routine extraction method which requires sufficient amount
of DNA to give the required results.
When using the direct PCR method on hair samples obtained from
individuals who commonly use hair waxes, they gave negative results.
However, when treated with some commercially available detergents and
physical treatment (gentle pull of the outer layer of hair follicles), the
scale of peak heights in all loci were increased. The samples treated with
the soap foam treatment gave the best results than other treatments. The
results were consistent when use one to three hair samples. Since most
people currently use hair waxes and chemicals, this test is of great
importance in criminal casework to obtain the DNA profile of Y
chromosome from the hair samples taken from these people.
The results of the Y chromosome DNA profile for (10) families;
each family has (5) males were obtained to reveal the extent of
convergence between these males from the same family. Also, the extent
of divergence and convergence between the families that was included in
this study, the effect of geographic nature and environmental conditions
on the results of the profiling data of these families. In this study, it was
possible to determine in certain percentages the extent of the divergence
and convergence between families as well as the geographical dimensions
and genealogy through the short tandem repeats on the Y chromosome.
There are tends for sons to their father or mother, as previous
studies have indicated about this tendency (dominant / recessive theory).
By paternity test, sons showed their tendency to their father or mother, as
this was determined by the scale of peak heights in the heterozygote
genetic loci. The correlation coefficients have revealed the tendency of
the sons to their father or mother in the same family. These genetic
tendencies refer to the physical and genetic characteristics that a child can
acquire from one parent to the other. These results are also an indicator of
genetic mutations and tendencies toward violence that have been
inherited from any of the parents.
DNA (Deoxyribonucleic Acid) is the genetic material present in
every cell of the human body. A child receives half of his or her genetic
material (DNA) from the biological mother, and half from the biological
father. During DNA testing, the genetic characteristics of the child are
compared to those of the mother. characteristics that cannot be found in
the mother must have been inherited from the father.
The genetic analyses in paternity and in forensic casework are
based on the detection of short tandem repeats (STRs), which are small
sequences of DNA made up of repeating units of 2–6 nucleotides. STR
markers located on autosomal chromosomes transmit to the next
generation in the Mendelian inheritance model where biological offspring
shares one allele from father and the other from mother on all the tested
loci. For each locus, one allele from the child must match one of the
mother’s allele for that region. The child’s other allele will match with
the biological father. It is the principle that is applied for determination of
parentage.
Current study was performed on 75 individuals who donated some
tissues voluntarily, which 125 biological samples were taken from them
and were divided into; 60 hair samples for Y chromosome direct PCR, 50
blood and saliva samples for Studying the relationship between males of
the same family and other ten families through the test of Y chromosome,
and 15 blood and saliva samples to study the tendency of children to their
father or mother and its relationship to morphological and physical
characteristics through the results of DNA STRs in paternity test.
Samples applied to different experiments were subjected to a group of
experiments which include:
1- DNA extraction.
2- Amplification of certain microsatellites.
3- Separation and detection of STR amplicons.
4- DNA genotyping.
- In addition to the samples that applied to the direct PCR method,
and compared with the samples that loaded by routine extraction
method.