On Wed, Mar 29, 2017 at 12:05 PM, John R Carpenter <jrcrin001(a)cox.net> wrote:
Normally we discuss such off list. My attempt to be general when I
should
have been more precise has caused confusion.
Yes, that's exactly the problem, and the only solution is to post the
corrections
on the list.
For the others on the list it may be a good idea to define the word
null.
I rather doubt that anyone on the list was hung up on the definition of "null",
especially since you explicitly referred to the zeroes reported by FTDNA
for markers that had been tested and yet not found.
I was using 2 ... having or associated with the value zero. Ø ... or
only
zeros as elements.
Yes, yes. Then again, it is worth pointing out that the zeroes
reported by FTDNA
are a serious misrepresentation of the truth. What FTDNA does in the lab is
measure the lengths of the various DNA segments containing the markers of
interest. For convenience, the lengths are given in terms of the number of
repetitions of the short repeating sequences that characterize these peculiar
markers. The truth is that a report of "0" doesn't mean that the measured
length was zero, but only that the lab couldn't find the marker at all. That
doesn't actually mean the marker is not there, but only that the lab didn't find
it. In the vast majority of cases, the zeroes really mean that there has been
a mutation in the flanking region that simply prevents the detection
of the marker.
Thus, the marker is generally present after all, but is not accounted for.
Please see our Carpenter Cousins X Site where only FTDNA results are
posted:
https://www.familytreedna.com/public/carpenter%20cousins%20%20dna/default...
Use keyword search for 372499 or scroll down to Group 98 to find the same ID
number. There you will see zeros ( 0 ) where the DYS marker was tested by
FTDNA and a value of zero ( 0 ) was given. This is where I was referring ...
His case is the only one in the Carpenter Cousins Project with null values.
Specifically where the null is reported as a zero ( 0 ).
Ah, but that is not true, as I pointed out once already. There are
quite a few other
cases of zeroes in the report. For example, if you scroll down and/or
search for
kit 11230, you will see a zero reported for DYS425. Several others are in the
same boat, but, interestingly, some of them are not shown in the
public view of the
X site because of the unfortunate default privacy "protection"
established by FTDNA.
Such kits are visible in the table only when the viewer is a member of
the project
and has logged into his own account at FTDNA and navigated to the
table from there.
On the Carpenter Cousins Y-DNA Web site, Table 1, Group 98 for 372499
we
used a dash ( - ) to represent the null values where the X site reported a
zero ( 0 ).
Right. The dash is a more precise reflection of the truth, signifying
"tested but
not found".
SMGF used a different process in collection
(mouth wash verses cheek swab) and a one pass verses two pass data reporting
without a verification check like FTDNA does.
It went beyond that. FTDNA would keep on testing more than twice, if necessary,
to get consistent, accurate results, while SMGF followed a policy of
"if at first you
don't succeed, give up and go on to the next sample." For that
reason, we simply
leave a blank for any marker that SMGF didn't report, instead of
inserting a dash.
And I wish to stress again, that null values as reported by FTDNA as
a zero
( 0 ) COULD represent sterility.
And, again, that is exactly where you go too far. As I keep repeating, only the
missing DYS464 is implicated, because of its closeness to the DAZ gene, and
because of its habitual four-way redundancy. Reported nulls are surprisingly
common, and you are unnecessarily spreading a false rumor that could cause
concerns for a lot of people. Please stop. Again, entirely missing DYS464 is
quite rare. I have not seen another instance in any of my other projects.
John Chandler