View Full Version : DF41 and CTS2501

05-17-2014, 02:23 PM
Thus far, every DF41+ man who has tested for CTS2501 has been CTS2501+ and vice versa. This can lead to the erroneous conclusion that DF41 and CTS2501 are just two different names for the same SNP. They are not. DF41 and CTS2501 are two different SNPs. This can be seen from their different positions on the y chromosome, as illustrated by ISOGG's YBrowse:

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DF41 (also known as S524 and CTS6581) is located near the middle of the first dark-shaded band from the centromere in the long, q arm of the y chromosome. CTS2501 (also known as S836), is located in the q arm in the light-colored band nearest the centromere.

I realize for many folks on this forum this is not news. I wanted to start this thread to point out to those with Geno 2.0 results that just because you got a CTS2501- result does not necessarily mean you are also DF41-. Geno 2.0 does not test for DF41, and we do not yet know which SNP came first. If DF41 is upstream of CTS2501, you could be CTS2501- and still be DF41+. If, however, CTS2501 is upstream of DF41, then all DF41+ men are CTS2501+, too, and a CTS2501- would mean that one is also DF41-. In that case, if one has a CTS2501+ result from Geno 2.0, he should still test for DF41, because it would be possible to be CTS2501+ and DF41-.

The point is, if you have Geno 2.0 results, whether you are CTS2501+ or CTS2501-, you still need to test for DF41 (unless you tested positive for one of the other, parallel SNPs).

05-17-2014, 04:30 PM
In princple I agree with everyone who gets a CTS2501+ to also test DF41, however if you belong to a one of the known STR clusters that is already proven to be CTS2501+/DF41+ then it's probably not worthwile to test. What will be interesting is any new STR clusters discovered.

05-18-2014, 12:49 PM
I would also like to see anyone who has a DF41- result test for CTS2501, with the exception of those who have already tested positive for some other, parallel SNP or who actually have CTS2501- results from Geno 2.0, Big Y or FGC.

If you tested with Geno 2.0, Big Y, or FGC and do not have a CTS2501+ result, then you are CTS2501- (unless you got a no-call on CTS2501).

But men who have tested DF41- as a stand alone, a la carte SNP could still theoretically be CTS2501+, if CTS2501 is upstream of DF41.

05-21-2014, 03:45 PM
Gamino, kit N87112, is now DF41+. Since he was CTS2501+ already, I was kind of hoping he would be DF41- and be the first to parse those two SNPs, but no such luck.