Forensic significance of DNA Profiling (Forensic biology)

Forensic significance of DNA profiling...
Forensic genetics biological specialization

1. Forensic significance of dna - profiling Submitted to – Dr.Sapna sharma mam Submitted by – Shabnam Roll no.- 1303

2. Index Introduction Disputed paternity case Child swapping Veterinary cases Plant testing Wildlife cases Missing person identity.

3. Introduction DNA profiling is a forensic technique which help to solve the cases in different aspects. The application of DNA profiling in disputed paternity cases , child swapping cases , missing person identification cases, agricultural cases ,plant testing etc. DNA profiling plays an important role in the field of forensics science to solve the various criminal cases.

4. Disputed paternity cases Paternity disputes cases arise when a father claims that he is not he biological father of that child , however mother claims that the man is the biological father of her child. These techniques of DNA – Typing help to solve such cases: Variable number of tandem repeats (VNTRs) Polymerase chain reaction (PCR) Short tandem repeats (STRs) Restriction fregmant length polymorphism (RFLP)

5. In case of alleged father

6. VNTRs VNTRs are the type of minisatellite in which the size of repeat sequence is generally 10 to 100 bp. Minisatellites are the type of DNA tandem repeats sequence that is sequence repeat one after another without other nucleotide in between them. This is about 10 to 100 nucleotides. The sequence of minisatellite are larger than the microsatellite (2 to 6 nucleotide). VNTRs can vary in numbers of repeats from individual to individual.

7. Conts . VNTRs profiling utilizes RFLP techniques which is the first historical method used in DNA testing. It utilize the “restriction endonucleases” that recognize and cleave the specific site along the DNA sequence which is reproducible set of restriction fragments of various length. Resultant different length of fragments produced will differ when the DNA is digested with restriction enzyme.This different pattern can be used to differentiate species from one another.

8. Y - STRs It’s a male specific technique and shows the patrilineage phenomenon. Hence, very useful in forensic DNA testing .And for investigation in sexual assault cases involving male suspects. The evidence gathered in such cases usually it consists of a mixture of high level of female DNA and low level of male DNA.In case of sexual assault, Y-STRs system is useful for determinig the number of unrelated male perpetrator in sexual assault cases. But YSTRs cannot distinguish between same patrilineage individuals.

9. Inheritance of Y-STR

10. Mitochondrial-DNA analysis It’s a female specific type of testing, mt.DNA is situated in cellular organalle within eukaryotic cell.Mt.DNA is circular in shape. May be useful in finding family relation of unknown person such as in disaster case Tzar Nicholas II , in solving historic puzzules and to link families. Having very useful in recovery of DNA environmentally demaged DNA is sometimes even possible with mt.DNA . But mt.DNA is cannot distinguished between same metrileneage or all same mothers.

11. Inheritance of mt.DNA

12. STRs A short tandem repeats is a region of genomic DNA containing an array of short repeating sequences. STRs technique is PCR based,applicable in degraded DNA,shows rapid results,show result in even small quantity DNA. Two major abandant used STRs kits are Promega coorporation and applied biosystem type kits which is used by forensic community.Manufacturer of STR kits provide allelic ladders that may be used for accurate genotyping kits from Promega coorporation and applied biosystems for comparable STR markers often contain different alleles in their allelic ladders.

13. STRs result interpretation

14. Child swapping Being parent and child caring is a wonderful experieance of everyone life. A baby swapping happens all around the world and a nowdays it is quite common newspapers and other media plateforms . Many time suspected from family members or hospitals staff.But now it can be detected by conducted a simple DNA test of intended infant with alleged mother.Mitochondrial DNA is compared with infant. There was a case happens in May 2015 in UK. Mr.Richard Cusworth and his wife Salvadoran case of child swapped.Maternity test prove the son Moses was swapped with another baby.

15. Veterinary cases The main applications od DNA testing in domestic animals for diagnosis of genetic disease and for sexing animals. In horses as well as other farm animals , selective breeding requires exact lineage records. The veterinary Genetics laboratory Forensic unit at university California , Devis is first accrediated to animals DNA profiling. The three main type of cases: Where animal is victim. Where animal is perpetrator. Where animal is witness.

16. Conts . Locard exchange principle maintain that every contact leaves traces,exchange can bear mute witness to each and every crimes. If you own a cat or dog, you know that their fur accomplished you throughout the day, from your home to your car ,from your car to your office.That fur (or saliva ,urine ,blood) can become crucial evidence in forensic investigations.Veterinary DNA profiling had been used in every state of US.

17. Plant testing Crimes often occurred in localized area containing the unique combination o botanical growth.If these plants,algae,grasses are sufficiently rare, then recovery of trace evidence from the clothing of a victim or personal property of a suspects may helpful in making that can link them to crime scene. In plant testing, two primary areas are currently being investigated. The first linking of plant material to suspect to make association link with crime was committed. The second linking marijuana to aid in forensic investigation.

18. Wildlife cases Often animals are tortured or killed by someone trying to controlled another person in domestic violence situations. Animal evidence can help to solve a wide range of cases from animal cruelty or theft,to the animal attack on humans or other animals. Pet hair is commonly collected item of non human biological evidence and not suited to individual ( neclear ) DNA profiling. However,unlike humans – dogs and cats hairs without root can yield enough DNA for individual DNA profiling. If the mt.DNA found in cytoplasm of all the anima cells can be tested to include or exclude contributor.

19. Non – human DNA identification When animals involve in an attack on a person.DNA typing may be used to identify the animal perpetrator. If the victim deceased then DNA evidence may be the only witness that an animal in custody committed the crime.Animal DNA testing exonerate the innocent animals.

20. Missing person identity Forensic DNA typing provides data from variety of materials and individuals and applied to many important issues that confront the society. DNA database house DNA profiles from convicted felons, forensic evidences, human remains and direct and family reference samples of missing persons. In forensic investigation of human reamains comes under two objectives To recover and examine the remains for criminal investigations including cause and manner of death. To identify if possible return to them to family of dead person.

21. Conts . This process id done by retrive the DNA and compare either from relatives of missing person ( hair, saliva, stains etc.). A shorter portion of DNA part, then STRs technique is useful in that case. Mitochondrial DNA recover easily from human remains. Sex chromosomes is possible to analyze a penal STRs that are located on Y-chromosome in order to match the remains with male relatives. It is more useful when close relative are not available for comparison because of petrilineage .

22. SNPs It refers to as single base difference in the sequence of DNA at particular point.SNPs are abundant in human genome, being used as linkage studies to track disease. Advantage : a) It give sufficient information to identify the human can be selected or identified. b) SNPs are smaller than STRs hence more useful than STRs in identification od degraded sample. c) SNPs show less mutation rate over STRs.

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