FAQ

This is a list of questions I have been asked and the answers that I gave. If you have a question that is not answered here please send it to me on the contact page.


How are the results divided.

The matches are graded into categories.
1. Immediate - Parent/Child, Siblings, Aunt/Uncle.
2. Close - 1st & 2nd cousins.
3. Distant - 3rd & 4th cousins.
4. Remote Cousin - 4th Cousin & 5th Cousin.


How accurate are the tests?

When your test is compared to another test, the software, compares how many matching alleles in each chromosome there are and the locations of the matching alleles. Based on the location and the number of alleles that match, the software calculates the relationship.

When a match of "Immediate and Close" is found between 2 tests,
the accuracy of the relationship is 99%
3rd cousin match is 90%
4th cousin match is 60%
5th cousin match is 30%


Do I need a new test if I have results from 23&Me

No, You can do a autosomal transfer at FTDNA that uses your existing raw test data from 23&Me and processes it through their software. It costs $69 for the transfer.


What does the ancestral heritage data mean.

In all of our chromosomes there are alleles that carry ancient ancestor DNA (1000+ yrs). Databases have been established of Ancient Markers used by anthropologists, to define the continents, sub-continents, and people groups these markers represent. Your results are compared to these databases to provide you with your ancestral heritage. In this test your results are based on both your parents heritage. It does not define which is paternal or maternal. There are other tests that can separately define paternal (Y-DNA test for men only) and maternal (mt-DNA test for women) heritage.


How many years will my results be in the Database

Your physical samples and test chip are stored at the Lab for 30 years.
Your results database file stays in the Family Tree DNA database indefinitely.


We received our test results a couple of weeks ago which show that our two adopted kids are siblings, but each of our kids had several 4th or 5th cousin matches, but none of their matches were in common. This seems very odd given that they matched as full siblings. It makes me question the viability of the cousin matches.

It is actually pretty common for siblings to get different sets of matches because of how DNA works and
how the software calculates a match. The phenomena is called genetic recombination/Chromosomal crossover.
http://en.wikipedia.org/wiki/Chromosomal_crossover

Only identical twins get the same exact version of DNA passed to them by the parents. For men each sperm
created has a different mix of your genes assembled to pass on. In men there are certain genes on the
Y chromosome that are always passed on, but on the other 22 chromosomes the mixture changes in each sperm.
In women the mixture of genes changes in all 23 chromosomes in every egg. This is how humans maintain
genetic diversity.

When the software is looking at the 900,000 markers it gives a letter or number as the results.
When 2 people are compared the software is just matching the letter or number results and counting
how many are a match.

While the siblings match on 90-95% of the 900,000 markers. A first cousin match will only match on about
50% of the markers and it goes down from there. Which markers for one child match his cousins are going
to be different then the markers the other child matches.

We actually see this alot in the testing for known relationships of everyone.


I was curious about one thing, more of an academic rather than practical question. As you pointed out, the 94% Southeast Asian category for my daughter combines Cambodian and Malay groups. Since these populations are not broken out into 2 separate subgroups, are these two subgroups so similar or identical that they are considered part of the same population group?. Since you sons results did not include Cambodian, it seems to indicate that there's a SE Asian Malay only ancestry population

Hi
South East Asia is a high level group that contains the subgroups; Cambodian and Malay and others. The East Asia group contains subgroups of India, Pakistan, Nepal, Tibet, Bagladesh. So because she has 4% Indian this represents that she has Angkorian roots. Which means her ancestors at some point probably lived in the Siem Reap region.

What I am trying to find out now is what does it mean for someone to have only Malay or only Cambodian as far as historical time migration patterns.

Also where does the North African, Middle Eastern, Jewish results come from as far as a migration pattern. I will add to this thread when I find out more about this question


Update to previous question;
The population groups represented in this result are populations that lived and migrated to South East Asia 1000+years ago, And are a combination of your parents ancestral heritage. Having a Khmer heritage result represents the indiginous Khmer population. Results that show Indian represent the Indian Migration that led to Angkor. Those with Malay result represent the migration of Malaysian peninsula to southeast asia. Those with North African/Middle Eastern result represent two possible explanations. In India there was a large Muslim middle eastern community on the west coast of India. Some of them possibly migrated during the great Indian migration to SE Asia 100BC-1000AD. Or a 2nd possible explanation is that Muslim sea traders made it too the Cambodian Coast after 1600AD. Because the Khmer Kingdom covered all of SE Asia and what now is Southern China, other Asian populations have been found in our results. Recently we had a results that shows the 1800's French Occupation, with 50% Western Europe-French and 50% Khmer/Malay.

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