Top 3 Techniques Used For DNA Testing

We all like to think we are special. That’s true because we are all unique beings! Everyone’s DNA is different because everyone gets a random mix of the genes from their mother and father, and that random mix is never the same for any two individuals.

Top 3 Techniques Used For DNA Testing

When unraveled, the DNA blueprint in every cell would stretch as long as two meters. The difference in DNAs is a very slight one. In fact, we all share around 99.9% of DNA with everyone else.

However, since we have such a large amount of DNA, that 0.01% difference is quite a lot.

Even identical twins have differences in their DNA, this is because during development (and lifetime entirely), people get tiny mutations (relatively permanent change in hereditary materials). These mutations cause the differences in individual DNA.

DNA related diseases are easily passed from parent to child. It is usually helpful when hospitals provide in office dispensing of drugs that treat heritable diseases, especially in cases of emergency.


What is DNA?

DNA or deoxyribonucleic acid is a long complex molecule composed of two chains that coil around each other to form double helix carrying information necessary to build and maintain an organism.

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All living things have these complex molecules within their cells.

The DNA also serves as the primary unit of heredity in organisms of all types. In other words, whenever living organisms reproduce, a portion of their deoxyribonucleic acid (DNA) is passed along to offspring. It is this transmission of all or part of an organism’s DNA that ensures a certain level of continuity from one generation to another.

This most famous biological molecule was discovered by James Watson and Francis Crick in 1953. It will interest you to know that if the entire DNA in a human body was unraveled, it would reach to the sun and back more than a whopping 300 times!


What is DNA Testing?

Up until 1984, the only method of establishing and authenticating personal identification was by the use of fingerprint process.

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A DNA test is a chemical test, in which an individual’s DNA is analyzed, for example to see if they have committed a particular crime or are the parent of a particular child. This is also known as DNA profiling or DNA fingerprinting.

When the analysis is done to identify a species, rather than an individual, it is termed DNA bar coding.

DNA testing uses chemicals to separate strands of DNA and reveal the unique parts of your genome. The results show up as a pattern of stripes that can then be matched against other samples for similarity.

To get your DNA analyzed, you would have to provide a sample of cells from your body. This can come from your sweat, saliva, blood, or other body fluids.

Swabs from inside your mouth, your skin or roots of your hair can come handy too. Blood is usually the best choice.


Uses of DNA Testing

Since it was invented in 1984, DNA fingerprinting has been useful for the following:

To Solve Court Cases and Legal Matters

It can be used to physically connect a piece of evidence to a person or rule out an individual as a suspect. DNA testing has often been used to settle paternal disputes as it can show who your parents, siblings and other relatives may be.

It can also be used to identify a dead body that is too old or damaged to be recognizable.

DNA Testing has Medical uses

It can help to match tissues of organ donors with those of patients who need transplants.

Diseases that are passed down through your family can be identified using DNA testing.

It can help find cures for those diseases, called hereditary conditions.

DNA profiling has also been helpful in the study of animal and plant populations in the fields of zoology, botany, and agriculture in general.


Top 3 Techniques for DNA Testing?

1. Polymerase Chain Reaction

The polymerase chain reaction (PCR) technique was developed in 1983 by Karry Mullis of the Cetus Corporation for use in research laboratories for establishing hereditary authentication.

The PCR analysis amplifies portions of the DNA molecules almost indefinitely using a smaller sample. In the polymerase chain reaction process, the DNA sample is denatured in to the separate individual polynucleotide strands through heating.

With the invention of this method, DNA profiling took giant strides forward on the forensic front as it became easy to identify fingerprints in criminal matters and in paternity tests.

The drawback was that it was not as discriminating as the restriction fragment length polymorphism (RFLP). It was also difficult to determine a DNA profile for mixed samples, such as vaginal swap from a sexual assault victim.

2. Amplified Fragment Length Polymorphism (AmpFLP)

This technique came into being in the early 1990’s and is still very popular in Developing countries involved in the process of DNA fingerprinting.

This technique relied on variable number tandem repeat (VNTR) polymorphisms to distinguish various alleles, which were separated on a polyacrylamide gel using an allelic ladder. Bands could be visualized by silver staining the gel.

This method which uses PCR to amplify the mini-satellite loci of the human cell proved to be faster than RFLP analysis.

It continues to remain attractive because it is highly automated, relatively less complicated operation and the cost-effectiveness.

3. Short Tandem Repeats (STR)

The short tandem repeat (STR) methodology for extracting DNA is known to be the most widely used form of DNA fingerprinting.

This system is based on the features of PCR, as it utilizes specific areas that have short repeated sequences of DNA. The STR analyzes how many times base pairs repeat themselves on a particular location on a strand of DNA.

Because unrelated people almost certainly have different numbers of repeat units in the loci of their DNA, this method can be used to discriminate between individuals that are unrelated.

The DNA fragments that result are then separated and detected using electrophoresis technique.

This method is advantageous in that the DNA comparisons can match the possibilities into an almost endless range.


What’s In Your DNA?

If you want to discover what’s in your DNA then please check out my Best DNA Guide. There are many, many different DNA testing kits that are on the market today, and my guide will show you which one is best for genealogy research.


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  1. Ben December 17, 2018
    • Owain December 17, 2018
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