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DYS 464

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DYS 464 (also written as DYS464, DYS#464, and DYS# 464) is a highly volatile (fast mutating) marker which was discovered at the University of Arizona by Dr. Alan Redd. Microalleles are sometimes seen in this marker.

From Family Tree DNA's Facts & Genes newsletter, volume 3, issue 2 (March 2004):

Marker DYS464 appears to be a rapidly changing Y chromosome marker and is a multi-copy marker. DYS464 occurs at least four times near the center of the Y-chromosome. The first four copies are called: DYS464a, DYS464b, DYS464c, DYS464d. Marker DYS464 is also known to occur more than four times, generally in African lineages of Haplogroup E. Additional copies of DYS464 are called: DYS464e, DYS464f, and so forth... DYS464 has an observed range between 9 to 20 inclusive. When testing a random sample of 679 males for DYS 464, scientists have found that the result 15,15,17,17 occurred in 10.6% of those tested, 15,15,16,17 occurred in 7.5% of the samples, and all the other results occurred less than 5% of the time, with over half these results only occurring once. This illustrates that Marker DYS464 is valuable in differentiating unrelated persons or splits in branches that have failed to show variation with other markers in the panel. In fact DYS 464 alone has a greater ability to split than the first 12 markers combined.

DYS 464 and infertility

A possible association with deletions on DYS 464 and infertility has been reported.[1] The question of infertility only arises in cases where DYS464 doesn't give you any readings at all, which may occur in about one out of two thousand men or fewer. That can happen when a big chunk of the Y chromosome is deleted. This chunk includes some genes involved in sperm production as well as DYS464, which doesn't code for anything itself. There are multiple copies of the genes, so most men have backups - if one copy is missing or defective, you can use another copy. But if all of the backups are missing, that is a known cause of infertility.

Calculating genetic distance

See the FTDNA FAQ in the Learning Center How does the infinite allele comparison method work for palindromic markers? for an explanation of how genetic distance is calculated for DYS 464 and other palindromic markers.

The archived FTDNA GAP FAQs (question #9) provide further background:[2]

I don’t understand how you calculated the difference at DYS 464.

DYS 464 was discovered at the University of Arizona by Dr. Alan Redd. This highly volatile (fast mutating) marker is included in the panel to help show changes even within family groups that are closely related. DYS 464 is replicated 4 times in 98.5% of people from Europe and the Middle East (the balance having 5 or 6 copies). Because the marker’s location on the Y-Chromosome is not determinable we sort the marker from smallest to largest (385a/b is treated the same way), and therefore it is possible to overstate or understate the actual genetic distance when making a comparison by eye.

The FTDNA Genetic Distance Report solves this potential problem as the actual difference is calculated for you.

Markers 464a-d are copies found at different locations on the Y chromosome. In about 1.5% of the test subjects, more than 4 copies will be present, representing Markers 464e, 464f, 464g. If those additional Markers are found, they are now shown on the individual's Y-DNA DYS Values page, and on the Group Administrator's Generate Y-DNA Scores page. If these additional Markers are not found, the columns for them in the reports will not appear. At the current time, 7 copies are the maximum number of Markers found for this DYS.

Results are always reported from low to high, when reading from left to right. When a mismatch occurs, it must be taken into consideration whether the number of apparent mismatches are a result of the order of presentation of the Markers. The order of the results for these Markers may make it appear as if there are more mismatches than are actually present. Here are two examples:

Results Genetic Distance
13 15 16 16
13 15 15 16 1

16 16 17 18
15 16 16 18 1

In the first example, the mutation did not cause the results to be reordered, so it is very clear that there is one mismatch. In the second example, if a 2 point mutation occurred (17-2 = 15) the loss of 2 repeats caused the results to be reordered. NOTE—464 shows more 2 step mutations then can be explained by the step wise model. On the surface, it looks like there are two mismatches, but this illusion is caused by the results being reordered, and there is only 1 mismatch, the 17 becoming the 15. Remember, DYS 464a-d is a highly polymorphic Marker; in fact it appears to be the fastest moving marker in our entire test. (Polymorphic means rapidly changing!) Evidence strongly suggests that DYS 464 follows the infinite allele model and therefore the visible 2 step change form 15 to 17 is treated as a single markers single mutation for comparison when the genetic distance report. Group Administrators, when comparing two individuals results, if it appears that there are more than 1 mismatch for Markers 464a-d, be sure to check the genetic distance report (Members Page of your GAP), to verify the number of mismatches, following guidelines set by the folks at the Lab for Molecular Science and Evolution at the University of Arizona.

DYS464X test

It is possible to order a special test to distinguish between the marker values. This test is available from FTDNA and YSEQ. There are two pages on Thomas Krahn's DNA Fingerprint website which provide further information:

Thomas Krahn also has information on the distribution of G- and C-types in R1b on the DNA Fingerprint website

Further reading

See also the DYS464 slides in Thomas Krahn's presentation on *Matching multicopy Y-STR markers in closely related individuals.

There is further information on the DYS464X test on John McEwen's website:

External links


  1. T E King, E Bosch, S M Adams, E J Parkin, Z H Rosser, M A Jobling. Inadvertent diagnosis of male infertility through genealogical DNA testing (letter). Journal of Medical Genetics 2005;42:366-368.
  2. The original link to this FAQ is no longer valid. Here is a link to the orginal page FAQ found in the internet archive.