DNA testing

KeskusteluGenealogy@LT

Liity LibraryThingin jäseneksi, niin voit kirjoittaa viestin.

DNA testing

1Cecrow
tammikuu 31, 2018, 9:30am

I've seen some interesting results from doing DNA testing offered by Ancestry.ca, connecting me with cousins near and distant and proving some branches of my tree I was uncertain about. For me it's been a positive experience.

I hadn't thought about potential downsides when I did the test, so I found this article interesting:
http://www.cbc.ca/news/canada/nova-scotia/dna-testing-privacy-terms-and-conditio...

It describes instances of discovering half-siblings, or adoption. Possible access to the information by insurance companies, etc. Things to consider before you test.

2.Monkey.
tammikuu 31, 2018, 10:50am

Yeah especially in the US, I would never get tested. It gives way too much info to way too many interested parties, with no protections. Until that changes...

3lesmel
tammikuu 31, 2018, 3:26pm

There was a "Dear Abby" in today's paper about this. The man writing in gave all his children a kit. Turns out his youngest child isn't his. Ex-wife had an affair unbeknownst to him. What to do? What to do?

DNA testing is a Pandora's Box even without all the extra privacy bits.

4Taphophile13
tammikuu 31, 2018, 5:15pm

I recently gained several cousins. On paper we aren't related at all but the DNA testing revealed their family story about great grandma may have had an affair must be true. NPEs (non-paternity events) are estimated at about 1-2% per generation so nobody's tree is completely accurate. I think the takeaway is if you can't handle the truth, don't test your DNA.

As for the man who now knows the child isn't genetically his, I hope Abby advised him to remember that he has raised and loved this child and that he should continue to do so. Families are much more than DNA, just ask any adoptive parents.

5lesmel
Muokkaaja: huhtikuu 27, 2018, 11:08am

>4 Taphophile13: The man was more concerned abt conforting his wife and/or telling his child abt the discovery. No mention of how he felt as a father.

6Cecrow
huhtikuu 27, 2018, 7:36am

Interesting headline in today's news:

DNA from genealogy site used to catch suspected Golden State Killer
http://www.cbc.ca/news/world/dna-from-genealogy-site-used-to-catch-suspected-gol...

7varielle
huhtikuu 27, 2018, 8:08am

I saw that. I suspect that technique will be used more and more to solve cold cases.

8amarie
toukokuu 7, 2018, 6:49pm

Don't forget for the cold case that the technology used was completely opt-in (though ethically dubious usage for a criminal case). People are not testing at Gedmatch, but uploading their own data to widen their matching possibilities. The larger commercial firms do not share such data with law enforcement.

Plus, ancestry-related DNA tests are not the same as criminal lab DNA testing. Different tech with different intentions. In this cold case it only led investigators to potential relatives, not a definitive match.

>2 .Monkey.: Discrimination and harassment based on disclosed genetic information is currently illegal in the U.S.: https://www.eeoc.gov/laws/types/genetic.cfm.

That said, individual bad actors and bias can ruin the best of all intentions.

9Cecrow
elokuu 2, 2019, 8:56am

Ancestry research (and DNA testing) could save your life.
https://www.nugget.ca/news/local-news/ancestry-dna-search-helps-save-womans-life

10Tess_W
joulukuu 27, 2019, 1:03pm

As a cancer survivor, it was necessary for me to have genetic testing to see if my cancer was genetic or not. At the same time I was offered the DNA testing for only $29 so I took advantage; it was exactly as I suspected as to national origin, etc.

11thornton37814
tammikuu 7, 2020, 8:56am

>10 Tess_W: The admixtures are always being refined. Different companies' results differ. Part of it lies in how the company defines regions. Part lies in the number of testers participating from their defined regions. The real value genealogically speaking is not so much in the ethnicity predictions as in the segment information which can be compared to other testers. That's why genetic genealogists have a love-hate relationship with Ancestry DNA. It's pool is the largest, but it does not offer a chromosome browser making it easy to compare segments. The trees are quite valuable, but it's really not enough for complex problems. Still the trees often help form hypotheses which can then be tested somewhere with a chromosome browser. We're fortunate some companies allow transfer of raw data. Unfortunately those companies tend to be the ones permitting law enforcement access which scares away some would-be testers and transfers.

12Cecrow
Muokkaaja: tammikuu 7, 2020, 9:03am

>11 thornton37814:, I've experienced that first-hand. An entire swathe of my DNA was reassigned from one region to another in their last update. I still suspect it's not in the right place, but it's closer.

13thornton37814
tammikuu 7, 2020, 9:15am

>12 Cecrow: I'm sure as the database grows more, it will be tweaked again. I just don't really like my Swiss ancestry being included in a British Isles grouping, but when you look at the underlying maps, it extends down to that area of Europe. I really think 23andMe's ethnicity estimates tend to be most accurate.

14mnleona
heinäkuu 9, 2020, 7:37am

I have been finding a lot of 5th-8th cousins on my research on Ancestry. I have written (message) to some to them.

15thornton37814
heinäkuu 9, 2020, 9:16am

>14 mnleona: I used to pay a lot of attention to the distant matches but as the database keeps growing, I find myself focusing on 4th cousin or closer matches which are easier to identify. I pay attention to more distant matches if they show up in common with or sharing a segment in which I'm interested (using 3rd party tool to view that segment data).

16mnleona
heinäkuu 14, 2020, 7:09am

I am trying to message "cousins" and have had some response. I have not found any close matches so far.

17thornton37814
heinäkuu 17, 2020, 9:12am

For those who tested with Ancestry, you will be losing access to your 6 cM and 7 cM matches as early as next month (or whenever the new algorithms are implemented) UNLESS you have done one of the following:

1) Corresponded with the match on the new messaging system
2) Assigned a match to a group with the colored dots
3) Made a note on the match

I began with those filtered 6-7 cM matches and then limited it to the ones with leaf hints (which means they are in ThruLines). One genealogist recommends doing 6-8 cM in case some of the 8 cM matches are slightly under the new 8 cM threshold and disappear. Because of the number of kits I have, I decided to do the 6-7 cM ones first and then go back and hit the 8 cM ones.

Roberta Estes' blog DNA eXplained offers a good overview on this and her approach. Other genealogy bloggers also commented.

Some genetic genealogists are not worried about the loss of the matches because segments that small are sometimes difficult to work with. I know that I'm working with problem-solving on some distant lines, and while I have some matches above that threshold, I have a lot in that low threshold that may be needed as I get further down the line so I'm taking the time to do it (even though I don't really have the time at the moment).

18mnleona
heinäkuu 19, 2020, 8:12am

19Cecrow
heinäkuu 23, 2020, 1:32pm

>17 thornton37814:, has Ancestry stated why they are removing them?

20thornton37814
heinäkuu 24, 2020, 10:52pm

>19 Cecrow: I think their official version would go along with the thought that small matches are less reliable. African-Americans are going to have most difficulty with the new algorithms followed by recent immigrants. The African-American kit I manage for a client has 100,000 fewer matches than most of my kits. A recent immigrant kit has 80,000 fewer. There are some petitions circulating as well as some pretty strong blogging to try to get Ancestry to change its mind. In the past, that has proved to be futile. They don't listen to their customers. Like many others, I suspect their real reason is to try to alleviate server problems without upgrading or replacing them. In other words, they are going for the band-aid instead of the cure.