На форуме rootsweb подняли тему о древней мутации, из-за которой практически все представители гаплогруппы N1c1 лишились части палиндрома Р1/Р2:
argiedude:
http://img9.imageshack.us/img9/6699/cdyabin11haplogroups.gifIn N1c1, CDYa is almost always equal to CDYb, such as CDYa/b = 36/36. In all other haplogroups, this only happens in about 15% of the samples. CDYa/b has a normal pattern of values, otherwise, with average diversity and values ranging from 34 to 39. But always with CDYa and CDYb glued to each other. It shows very clearly in the graph I posted above. The blue line is CDYa, the red line is CDYb. The difference with all other haplogroups is obvious.
Gareth Henson: This is because haplogroup N had an ancient RecLOH event which deleted part of the P1/P2 palindrome area. In reality there is only one copy of CDY present but the lab always interprets the graph as two copies with the same value. For the same reason DYS464 usually has a AABB pattern reflecting the presence of only two copies (and also DY459 which is usually 9-9 or 10-10 - again really only one copy).
The "Palindromic Panel" of advanced STRs was developed partly in order to increase our understanding of these sorts of events. Haplogroup N is unusual in that the recLOH was so ancient that it appears to be shared across a major subclade.
Does anyone know of any complete Palindromic Panel results for an N?
Thomas Krahn: Yes, correct.
Almost all N1c1 Y chromosomes that I have tested have a deletion in the
P1/P2 region. You may have a look at the results from the advanced testing.
(I believe I have seen a very few cases who then had a subsequent
duplication of the deleted ChrY, but this is a different story).
Therefore they have only ONE copy of DYS724 (=CDY), ONE copy of DYS459
and TWO copies of DYS464.
Other haplogroups like J-L25 have a P1/P2 duplication and have really 3
alleles at DYS724.
I like the way you've displayed those alleles. It makes this immediately
visible. You may try to do the same for DYS459 and DYS464.
Проверил по своему гаплотипу:
CDYa/b = 35/35, всего ОДНА копия,
DYS464 = 14-14-15-15, всего ДВЕ копии,
DYS459 = 10-10, всего ОДНА копия.
Порушен у меня палиндром P1/P2...
Век живи, век учись.