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DNA Sequencing

DNA Sequencing

Author: Amanda Soderlind

Understand how DNA is mapped and understood

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Source: Video and Images Created by Amanda Soderlind

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Welcome to this lesson today on DNA sequencing. Today we're gonna be talking about the process of DNA sequencing as well as some of the uses for DNA sequencing.

So, DNA sequencing provides us lots of information about genes. We can find out a lot of information about our genes because of this process. So, some of the information it provides us is the location on a chromosome where a gene is located. It can tell us about the order of nucleotides involved in a gene. So if we want to know about the specific order of nucleotides that is involved in a specific gene, DNA sequencing can tell us about that. It can teach us how a gene functions, it can teach us about mutations of a gene, and it can let us know how genes interact with other genes. So, we can find out a lot of information about genes through DNA sequencing.

And so this DNA sequencing can be really beneficial in the medical world because if we understand how genes work, where they're located, the order of nucleotides, how they function, how they interact, we can gain more information about certain types of genetic disorders. And it can aid in research of genetic disorders.

It's also useful in genomics. So, a genome is all of the DNA in a species' entire set of chromosomes. So, genomics is the study genomes. So as I mentioned, a genome is all the DNA in a species' entire set of chromosomes. So, a variable number tandem repeat is a region of DNA that varies from person to person. Now, more than 99% of all human DNA is the same.

So, if you think about it, it's kind of mindblowing to realize that more than 99% of all human DNA is the same, regardless of color, ethnicity, whatever. 99% is the same. So this small amount that varies from person to person is called the variable number tandem repeat.

So, and of that small amount that varies from person to person, you have a unique combo of repeats. A unique combination of repeats of nucleotides that basically is like your genetic fingerprint. And so this is what is used in forensics if people are doing blood tests or DNA tests. They're using this small sequence, this small amout of your DNA that is unique to you.

OK? So, it's just kind of interesting to realize how much DNA there is in an entire genome and then how much of it is specific to a person. Such a small amount is very specific to a person.

So, the Human Genome Project basically was a project that mapped the complete human genome using DNA sequencing. So, this was a huge project because there are over 3 billion nucleotide bases in a total of about 21,500 genes. So the human genome consists of 21,500 genes and 3 billion nucleotides.

But the knowledge of this information, as I mentioned a little bit earlier, is that it's very, very helpful in the research of genetic disorders and it's very, very useful with medicine. So, it provides us with this knowledge that we can use in the medical field.

This project also mapped around 20,000 protein-coding genes. So, less than 2% of DNA is coding for protein. And the rest of DNA is non-coding DNA. So, the rest of DNA does not code for proteins. And it's referred to as junk DNA because it doesn't code for these proteins.

However, we can't just assume that because it doesn't code for proteins it has no purpose whatsoever. So what biologists are working on now is trying to figure out what the purpose of this junk DNA is. If it doesn't code for proteins, then what does it do?

So, DNA sequencing has been very useful in the medical field and it has provided us with a lot of information about how genes function, where they're located, and how they interact with other genes.

So, this lesson has been an overview on DNA sequencing.

Terms to Know
DNA Sequencing

A genetic technology that allows us to characterize and leverage genes.


All of the DNA in an individual's complete set of chromosomes.


The study of genomes.

Human Genome Project

A map of the entire human genome completed with DNA sequencing.

Variable Number Tandem Repeats

The portion of DNA (about 1%) that is unique to each individual.