How Do You Do a DNA Comparison?
DNA makes up the genetic material of all species on Earth. Every individual has slight variations in less than 0.1 percent of the genetic material. Since the DNA material of a species consists of several million segments, this is sufficient to identify individuals. This means you can compare DNA from one individual (or species) with another.
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Instructions
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Retrieve the samples to be compared. Make sure they do not contain mixes of genetic materials, as this will make the analysis more difficult.
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Extract the DNA. This is typically done using specialized reagents and materials.
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Mix the reagents with the PCR or other analysis reagents. PCR is a process which creates multiple duplicates of a DNA segment.
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Separate the amplified DNA from the reagents and other materials.
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Insert the samples into the analysis equipment. DNA analysis can be performed using chemical staining, but is normally done using a spectrometer, because different chemical substances reflect light differently and that is used to create an individual spectrum for each sample.
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Receive the result into appropriate computer software for further analysis.
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Compare the readout with either another sample or a sample previously stored in a database.
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Tips & Warnings
When comparing DNA samples for forensic purposes, a number of analyses are performed on the samples to exclude any possibility that the the DNA samples are not a match.
All criminals in the U.S. have DNA analysis stored in a separate database run by the FBI, so criminals can often be identified by comparing the DNA at a crime scene to DNA analysis stored in the database.
Even after a number of tests, 100 percent probability that two DNA samples are a perfect match can not be guaranteed.
To perform DNA analysis correctly, you have to have very specialized training.
References
Resources
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