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There is a paragraph titled "MHC Proteins Are the Most Polymorphic Human Proteins Known" in the "Molecular Biology of the Cell" by Alberts et al. 6th ed. 2014.

But someone has recently told me that it is not the case making an example of a set of genes helping to identify persons in forensic medicine. (I didn't remember the genes.) Is it true?

Are MHC proteins the most polymorphic human proteins known?

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    $\begingroup$ In addition to the excellent answer given by @Amory, it might be of interest for you that this not only applies to modern humans but also appears to be true for archaic humans (Neandertal and Denisova), even though the latter had far lower overall genetic diversity. $\endgroup$ – AlexDeLarge Oct 28 '16 at 14:39
  • $\begingroup$ I don't think the markers used in forensic DNA fingerprinting code for proteins. $\endgroup$ – swbarnes2 Oct 28 '16 at 18:15
  • $\begingroup$ Are we restricting things to germ-line polymorphism, or is there some other reason to exclude immunoglobulins? $\endgroup$ – R.M. Oct 28 '16 at 19:08
  • $\begingroup$ @AlexDeLarge: you mean MHC locus was also diverse in the archaic humans? Thank you for your comment. $\endgroup$ – stan Oct 29 '16 at 7:42
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    $\begingroup$ @stan: Yes, looking at archaic genomes one also finds MHC genes to be among genes with highest diversity. $\endgroup$ – AlexDeLarge Oct 30 '16 at 9:17
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Yes. There are many MHC (MHC in humans is called HLA) genes. The classical loci — Class I A, B, and C, and Class II DP, DQ, and DR — are the most polymorphic.

Here's a table from a 2002 article which clearly shows the number of polymorphisms. It's no contest.

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It's worth me pointing out that those numbers are wildly out of date. The IPD-IMGT/HLA can provide full lists of known HLA alleles, but the exact numbers are in the tens of thousands:

enter image description here enter image description here enter image description here


The person you spoke with was probably referring to sequences called microsatellites. These are small regions that are polymorphic and quite variable between individuals, and using a number of these together can be useful for genetic fingerprinting, but each individual microsatellite will not be as polymorphic as HLA class I A, for example.

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