Y ACCURATE

[brownbagg]

if i got another y test with the same company, using a new test kit, would my markers be identical?

[rod]

if i got another y test with the same company, using a new test kit, would my markers be identical?

The y-12 through y-111 tests should be. The big-y test has enough errors that it's likely you wouldn't be 100% identical to yourself.

[LarryBurford]

Wow. If I spent that much on big Y I would not expect errors.

[lgmayka]

Wow. If I spent that much on big Y I would not expect errors.

"Errors" is not really the best term here. The Big Y examines 10 million locations on the Y chromosome, many of which are not useful for a typical haplotree:

- Some locations are in a segment very similar to a segment on another chromosome. This can result in false readings.

- Some locations are in a segment duplicated elsewhere on the Y chromosome. This can result in mixed readings.

- Some locations have changed state multiple times in the same haplogroup. This obstructs simple naming of the clade and may even make its placement uncertain.

The bottom line is that the Big Y's results require expert interpretation.

[brownbagg]

how accurate are the people testing the sample. How do we know they didnt switch a sample by accident, had two or three on the counter, drop the paperwork, which goes with which. how do we know my results are my test samples?

[dna]

how accurate are the people testing the sample. How do we know they didnt switch a sample by accident, had two or three on the counter, drop the paperwork, which goes with which. how do we know my results are my test samples?

Compare your Y-DNA37, or whatever results you have, with those obtained from Big Y.

That is not 100% foolproof, but it is an easy check.

Mr W

[lgmayka]

how accurate are the people testing the sample. How do we know they didnt switch a sample by accident, had two or three on the counter, drop the paperwork, which goes with which. how do we know my results are my test samples?

That kind of thing has happened, rarely, in the past. But FTDNA has, over time, incorporated additional precautions and double-checks to make a sample swap extremely unlikely on a recent sample.

At one time FTDNA had a $50 re-test policy: For $50, they would re-run one marker panel (on a new sample?). If the results ended up different from the original run, they would refund your $50.