DNA fingerprinting presentation for B.SC

DNA fingerprint

1. 3T THIRD YEAR HONOURS

2. VNTR A variable number tandem repeat (or  VNTR ) is a location in a genome where a short nucleotide sequence is organized as a tandem repeat. These can be found on many chromosomes, and often show variations in length between individuals . Minisatellites and their shorter cousins, the  microsatellites , together are classified as  VNTR  (variable number of tandem repeats) DNA.

3. WHAT IS TANDEM REPEAT? A  tandem repeat  is a sequence of two or more DNA base pairs that is  repeated  in such a way that the  repeats  lie adjacent to each other on the chromosome.  Tandem repeats  are generally associated with non-coding DNA. In some instances, the number of times the DNA sequence is  repeated  is variable . An example would be: ATTCG ATTCG ATTCG in which the sequence ATTCG is repeated three times

4. MICROSATELLITE   microsatellite  is a tract of repetitive  DNA  in which certain  DNA motifs  (ranging in length from 2–5  base pairs ) are repeated, typically 5–50 times .  Microsatellites occur at thousands of locations within an organism's  genome ; additionally, they have a higher  mutation  rate than other areas of DNA  leading to high  genetic diversity .

5. The name  "satellite"  refers to the early observation that centrifugation of genomic DNA in a test tube separates a prominent layer of bulk DNA from accompanying "satellite" layers of repetitive DNA . Microsatellites are often referred to as  short tandem repeats  ( STRs ) by forensic geneticists, or as  simple sequence repeats  ( SSRs ) by plant geneticists.

6. MINISATELLITE A  minisatellite  is a tract of repetitive  DNA  in which certain DNA motifs (ranging in length from 10–60  base pairs ) are typically repeated 5-50 times. [1]   Minisatellites occur at more than 1,000 locations in the  human genome  and they are notable for their high mutation rate and high diversity in the population. Minisatellites are prominent in the  centromeres   and telomeres  of chromosomes, the latter protecting the chromosomes from damage.

7. DNA FINGERPRINTING DNA profiling  (also called  DNA fingerprinting ,  DNA testing , or  DNA typing ) is a forensic  technique used to identify individuals by characteristics of their  DNA . A  DNA profile  is a small set of DNA variations that is very likely to be different in all unrelated individuals, thereby being as unique to individuals as are  fingerprints  (hence the alternate name for the technique). DNA profiling should not be confused with  full genome sequencing . The modern process of DNA profiling was developed in 1988 by  Alec Jeffreys

8. PRINCIPLE Although 99.9% of human DNA sequences are the same in every person, enough of the DNA is different that it is possible to distinguish one individual from another, unless they are  monozygotic ("identical") twins .  DNA profiling uses repetitive ("repeat") sequences that are highly variable  called  variable number tandem repeats  (VNTRs), in particular short tandem repeats (STRs), also known as  microsatellites , and  minisatellites . VNTR   loci are very similar between closely related individuals, but are so variable that unrelated individuals are extremely unlikely to have the same VNTRs . These sequences occur near telomere, centromeres , Y chromosome and hetero­chromatic area. The area with same sequence of bases repeated several times is called repetitive DNA.

9. PROCESS

10. Applications of DNA Fingerprinting : ( i ) Individuality: Like skin finger printing ( der - matoglyphics ), DNA finger printing can help to distinguish one human being from another with exception of monozygotic twins , (ii) Paternity/Maternity Disputes: DNA finger printing can identify the real genetic mother, father and the offspring , (iii) Human Lineage: DNA from various probables is being studied to find out human lineage , (iv) Hereditary Diseases: The technique is being used to identify genes connected with hereditary diseases , (v) Forensics: DNA finger printing is very useful in the detection of crime and legal pursuits. DNA fingerprinting has proved that Dhanu , the human bomb, was the real murderer of Shri Rajiv Gandhi, the former Prime Minister of India , (vi) Sociology: It can identify racial groups, their origin, historical migration and invasions. Genography is the study of migratory history of human species .

11. THANK YOU