How safe is this match?

[lullaby]

I know this is a difficult one to answer but I should appreciate any thoughts.

I have been searching for my West Indies' ancestors for about 15 years without a great deal of success.   This concerns my 3xgt grandfather on my father's maternal side who was born in Tortola (now part of BVI).   My query relates to a specific Gedmatch DNA match of a total of 14.8cM spread over 5 segments, the longest of which is 4.6cM.  This is a brief summary from a few years back which I am able to comprehend.

Their updated results are - 4.6cm largest segment: total half match segments (HIR) 34.4cM (0.96 PcT): 10 shared segments: 631251 SNPs used for this comparison: 52.056 PcT SNPs are full identical.  Sorry, but I don't think I will ever understand all this detail!

I know small amounts inspire very little confidence but, bearing in mind that this involves several matching segments, how much interest and confidence should I in fact be giving this match and the family knowledge that he has given me?  The surname is obviously correct and his family connection is with Montserrat which at the time was closely linked to Tortola.   It is several years since we were in contact.

Thanks for your interest and in advance for your advice.

[melba_schmelba]

I know this is a difficult one to answer but I should appreciate any thoughts.

I have been searching for my West Indies' ancestors for about 15 years without a great deal of success.   This concerns my 3xgt grandfather on my father's maternal side who was born in Tortola (now part of BVI).   My query relates to a specific Gedmatch DNA match of a total of 14.8cM spread over 5 segments, the longest of which is 4.6cM.  This is a brief summary from a few years back which I am able to comprehend.

Their updated results are - 4.6cm largest segment: total half match segments (HIR) 34.4cM (0.96 PcT): 10 shared segments: 631251 SNPs used for this comparison: 52.056 PcT SNPs are full identical.  Sorry, but I don't think I will ever understand all this detail!

I know small amounts inspire very little confidence but, bearing in mind that this involves several matching segments, how much interest and confidence should I in fact be giving this match and the family knowledge that he has given me?  The surname is obviously correct and his family connection is with Montserrat which at the time was closely linked to Tortola.   It is several years since we were in contact.

Thanks for your interest and in advance for your advice.

Can I ask which DNA company test this was from? As you say, using segments smaller than 6cM is risky as such a link might just be related to multiple very ancient lines of descent i.e. 400 years or more even.

[lullaby]

My test was with FT dna and his would have been with either FT or 23andMe - perhaps the latter.   It dates back about 10 years.

Thanks

[melba_schmelba]

My test was with FT dna and his would have been with either FT or 23andMe - perhaps the latter.   It dates back about 10 years.

Thanks

When was your FTDNA test taken? I am asking because tests based on the GSA chips i.e. FTDNA and MyHeritage from around 2019, 23andme from 2017, produce very inaccurate matching on GEDMATCH. If you supplement it with a Ancestry test and make a superkit the matches will be much more reliable.

[lullaby]

My FTDNA test dates back to January 2013.   I'm unable to find a date for the GEDmatch download but it would be a year or so later.   My contact with the person involved also dates to around this period.

So you are recommending that I also download my Ancestry DNA results to GEDmatch - I must confess I hadn't thought of that at all!

[Biggles50]

If you have not taken on then an Ancestry DNA test will provide access to what is probably one of if not the largest database.

Then upload the raw data to all the free comparison websites and wait until they each have completed the searches before looking at the results.

If the Ancestry test is anywhere near your other test then 35 cM at worst case could be at 7xGGP level so potentially a massive tree

[lullaby]

Thanks, Biggles.   I have tested over the years with all but 23andMe without resolving this issue.   I have identified matches with members of the family line in question but all date from my 3xgt grandfather to present.   The usual problem - family trees are few and far between -  and I guess they have also hit the same stumbling block.   The answer is probably out there hidden amongst the 'no shared matches' statement.

[melba_schmelba]

My FTDNA test dates back to January 2013.   I'm unable to find a date for the GEDmatch download but it would be a year or so later.   My contact with the person involved also dates to around this period.

So you are recommending that I also download my Ancestry DNA results to GEDmatch - I must confess I hadn't thought of that at all!

Ah, well you are safe then . The GEDMATCH database is actually based on the original FTDNA SNPs so you couldn't really get a better upload . You could of course upload your Ancestry results and combine to superkit which may give you a few more SNPs to match with.

[lullaby]

Oh Melba - thank you, thank you, thank you!   I feel as if a weight has been lifted off my mind as I have been wondering about this for such an age - it feels like forever.   Obviously I won't take this as 100% but my work on the history I have compiled based on his information wasn't perhaps all in vain.

I shall upload (I still get confused between down... and up...) my Ancestry onto GEDmatch and it has struck me that I used my Ancestry dna for My Heritage so perhaps it may be worth testing with them direct.

Lesley