FORENSICS Cabanto, Ecat, Talampas, Vocal, Beleran, Mina IV-Gluon

DNA fingerprinting: Overview Sir Alec Jeffreys Also known as genetic fingerprinting or DNA profiling Way of identifying an individual* Applications  Forensics  Paternity/Maternity tests

Why it is better than a fingerprint. Fingerprints are easily obscured DNA is in every cell of the body  Hair strand  Skin follicle  Drop of blood

How it works 99.9% of our genes are identical The remaining 0.1% is used to determine the individual Microsatellites  Short repetitive sequences that are highly variable in humans  Reflect individual genetic make-up  A.k.a. Variable Number Tandem Repeats (VNTR)

VNTR’s short sequence in the introns of DNA that is repeated in a head-to-tail manner at a specific chromosomal locus interspersed in genome Number of repeated units vary per human Loci – VNTR’s  One VNTR – 17 bp, repeated 70 to 450 times  Total: 1190 to 7650 base pairs

Southern hybridization DNA with VNTR is cut with a restriction endonuclease Size varies, creating RFLPs, or restriction fragment length polymorphisms

Analysis Leads to a two-band pattern Inherited from each parent One band can occur if parental bands are identical/nearly the same

Basic Genetic Principles Identity matching  VNTR alleles should be the same if samples are from the same individual. Inheritance matching  He or she could have VNTRs inherited from his or her mother or father, or a combination  Never a VNTR either of his or her parents do not have.

Other Uses Personal Identification  Casualties  Paternity/Maternity testing  Family reunions yehey :D

Other Uses Diagnosis of inherited disorders  Alzheimer’s disease  Huntington’s disease Determining risks of having an affected child Identify patterns associated with disease May lead to cure for the disorder

Other Uses Mapping genography  Find patterns of migration  Trace human species’ history National Geographic Society  Study distinct trail left by humans since we left Africa  Understand more about our background

In the Philippines Case study: Ray de Villa Jan. 9, Arrested for the rape of 13 yo niece DNA testing was not done at that time Sole evidence was birth of a child Counter evidence – 76 yo suspect suffered physical condition

Case Study Victim did not report assault until confronted of pregnancy Problem: Court did not allow paternity testing Dr. Cora de Ungria of UP devised a way to be able to profile the child’s paternity

Both parties (child’s family and prison) refused for samples “Spitting game” to get saliva from child and 4 other children Blood from De Villa without assistance from prison staff Results: genetic markers proved that De Villa could not have fathered any of the children

Parole was granted to De Villa after extensive legal action Since then, Philippine Parliament has introduced DNA database legislation and the Supreme Court has issued rules for the admission of DNA profiling results in court

UP Diliman’s DNA analysis lab has also created a “rape kit”- Sexual Assault Investigation Kit for the Collection of Biological Samples

In the Philippines Crop biology  analysis of genetic diversity within breeding populations in plants  Differentiation between cultivars  Identification of plants containing a gene of interest

Issues Privacy of suspects Studies regarding human population DNA evidence may place a person at a crime scene, but it also does not necessarily mean that he or she committed the crime DNA can still be tampered with, and still be used to frame people

Issues Pattern narrows down a million people to around 2-10 Sometimes cannot identify individual However, if there are suspects in hand, the match can be easily made