Re: DYS 389 on Genographic Project Results #dna
Rachel, the DYS 389-1 and 389-2 markers are overlapping. In the case you
show, the absolute values would be 14 and 31. They are sometimes reported,
especially in comparison tables, as 389a and 389b, with 389b representing
the difference after 389-1 is subtracted >from 388-2, so that a single
mutation in the overlapping portion will not be double-counted. If there
is only a single mutation and and it is in the overlapping portion, it
will show only for 389-1 (or 389a), the shorter marker, after the
subtraction. If there are two mutations in the longer 389-2--one in the
overlapping portion, one not--they will both show, but separately, after
the subtraction. One will show for 389-1, the other for 389b, the
difference after subtraction.
Whether the two DYS 389 marker designations are followed by numbers or
letters, the surest way to determine if the subtraction has been made
is >from their relative values, as you sensed. If they are about the same
size, the subtraction has been made. If one is about double the other,
the subtraction has not been made, and will have to be done before
samples can be compared for the genetic distance between them.
In a message dated 11/22/2009 Rachel Unkefer rachelunkefer@...
[The DYS marker values] in question are as follows:
Now, I've done a small amount of research about this marker and found
that some places use "a" and "b" instead of "1" and "2" and assign the
DIFFERENCE between the total and "a" to "b". Most of what I've read
does not indicate that is a standard way of expressing "1" and 2". 17
does not seem to be a reasonable value for 389-2, but if I add 14 and
17 I get 31, which matches all the other men in the project. Is this a
correct interpretation of the Genographic Project results?
Thanks for your help