DNA individuality

There are a lot of tiny difference between each human's genomes.
It's various for example, difference in a chromosome, in pattern of repeat and so on.
The individual variation of genome makes the difference.


Above all, SNP is the most popular. It stands for Single Nucleotide Polymerphism.
SNP is a DNA sequence variation which one bese is defferent from popular one.
We can see SNPs in a ratio of one to a 500〜1000 bases, so it is said that we have about 10 million spots like that.

Popular sequence

SNP sequence

As you look, it is another base the third one from left.

SNPs influence the living things' bodies, because it is difference of DNA sequence.
For example, if sequence coding important protein is untypical, he is easier to get some diseases than other people.

The easiness of getting diseases does not depend on only one SNP.
Usually, it is due to 10〜20 SNPs and this is called "the hereditary predisposition".
Each hereditary predispositions have different influence one by one, so if you have it, sometimes it doesn't appear.
In the other words, some bases carry out important role of a living things' life, other ones have no tasks for them.

Significantly, it does not depend on just the hereditary predisposition, it is related to the surrounding environment.
If you know the risks of SNP by genetic test, you can prepare and prevent diseases effective.


"Microsatellites" is a variation of a DNA sequence which repeat same order of 2〜4 bases dozens of times.
People don't have the same the number of its times even though you check the same spot. Same sequences often make mistakes of copying, so the difference stands out.
We can see SNPs in a ratio of one to a 30〜100 thousand bases, so we have about 100 thousand spots like that.
Microsatellites is, so to speak, STR in the criminal investigation.
In the criminal investigation, microsatellites is also called "STR".


Some such difference appears on our bodies, others doesn't influence.
The important thing is to remember we have own variations without exception.

Though, human being is less variations in each of them than other living things.
It is because of that human being is young animal for dividing into them and chimpanzees about 5 million ago.
We may be green hand of nature from the view of a diversity.

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