Genetic fingerprint

In the human cell there are 23 pairs of chromosomes containing approximately 3000 million base pairs of DNA. Short sequences of DNA, perhaps with as few as 20 nucleotide units and sometimes radiolabeled, can be obtained either by chemical synthesis (gene machine) or from cloning. These short sequences can be used to probe for a complementary sequence by looking for the position to which they bind to any DNA sample under investigation, from blood for example. Such probes can detect as little as 100 fg of DNA and are the basis of forensic genetic fingerprinting tests. 

Genetic Fingerprinting Using PCR Amplification of MicrosateKite Sequences... 

First DNA based method for genetic fingerprinting developed by Alec Jeffreys... 

Marker-assisted breeding The use of genetic fingerprinting techniques to introduce genes of interest from one plant variety to another. Relies on knowledge of DNA sequences in a particular genomic region. 

DNA fingerprinting (genetic fingerprinting) The use of a pattern of DNA fragments obtained on restriction analysis of certain highly variable repeated DNA sequences, e.g. tandem repeat sequences which are virtually unique to an individual. This DNA profile , which can be detected in minute amounts of cells (e.g. in blood or semen), can be used in criminal cases and paternity suits. 

Engelen, B., Meinken, K., von Wintzintgerode, F., Heuer, H., Malkomes, H.P. and Backhaus, H. (1998) Monitoring impact of a pesticide treatment on bacterial soil communities by metabolic and genetic fingerprinting in addition to conventional testing procedures. Applied and Environmental Microbiology, 64, 2814-2821. 

Genetic fingerprint of monozygotic twins (columns 2 and 3) and their parents (columns I and 4). The arrows indicate hypervariable sequences inherited from the father. Similar hypervariable sequences can be identified from the mother. [Reproduced with permission from A. J. Jeffreys,... 

Another type of polymorphism is called a variable number tandem repeat (VNTR). Here the restriction sites flank a region of the genome whose length varies between individuals due to different numbers of copies of a specific sequence (a tandem repeat ). The restriction fragment pattern obtained using probes which identify different sequences is almost completely unique to an individual and can he used as a genetic fingerprint . 

---