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DavidCoutts
06-11-10, 03:53
Hi,

I was reviewing my GeneBase results when I noticed that I had tested Positive for P25. Mr Google was unable to provide me with any answers as to what L21+/P25 actually means. The only referances I found were to articles stating that P25 is "unreliable".

If anyone hear would care to speculate on the possible significance(if any)of P25, I'd be very interested in reading it.

Thank you,

David.

secherbernard
06-11-10, 09:10
Hi,

I was reviewing my GeneBase results when I noticed that I had tested Positive for P25. Mr Google was unable to provide me with any answers as to what L21+/P25 actually means. The only referances I found were to articles stating that P25 is "unreliable".

If anyone hear would care to speculate on the possible significance(if any)of P25, I'd be very interested in reading it.

Thank you,

David.
P25 is a SNP upstream L21. So P25/L21 means only L21. See http://isogg.org/tree/ISOGG_HapgrpR.html

Maciamo
06-11-10, 09:56
P25 is a defining mutation of R1b1. However it is a fickle mutation and back mutations are found in about 25% of R1b lineages.

DavidCoutts
06-11-10, 13:49
P25 is a defining mutation of R1b1. However it is a fickle mutation and back mutations are found in about 25% of R1b lineages.

So just because one is P25 positive, that does not automatically mean one is R1b1? Hence my L21+, correct?

Maciamo
07-11-10, 09:10
So just because one is P25 positive, that does not automatically mean one is R1b1? Hence my L21+, correct?

I am not sure I understand your question. P21 defines R1b1, while L21 defines R1b1b2a1a2f. Theoretically all R1b1b2a1a2f should have P21, L21 and all the mutations in between on the tree. P21 however is special due to its fast mutation rate, so that about 25% of R1b1b2a1a2f might actually be negative for P21 when they should be positive.