3rd-5th cousin match on FTDNA does not show up on AncestryDNA?

[Matt62]

As stated in the title, I have a 3rd-5th cousin match on FTDNA who has told me that he has also tested with AncestryDNA but does not appear as a match to me there. How is that possible?

[hansonrf]

Presuming you both have tested at Ancestry.com and used the 'new' Ancestry.com (autosomal) test:

How strong (cM, number of segments) a match are you on FTDNA?

Likely answer is it is a weak/marginal match that just meets FTDNA's limits but is under Ancestry's thresholds.

Have you uploaded both sets of both of your data to GedMatch?

What does GedMatch say and what are the kit numbers?

[hansonrf]

The following link might help with the likelihoods... Across platforms [like GedMatch or an import] would logically be less than or equal based on SNPs in the different tests.

https://www.familytreedna.com/learn/autosomal-ancestry/universal-dna-matching/probability-relative-share-enough-dna-family-finder-detect/

[jbarry6899]

The following link might help with the likelihoods... Across platforms [like GedMatch or an import] would logically be less than or equal based on SNPs in the different tests.

https://www.familytreedna.com/learn/...finder-detect/

Ancestry uses a proprietary program called Timber that eliminates or adjusts matches in "pile-up regions," that is regions of the genome where you have a large number of matches, which could be related to a shared physical characteristic or distant ancestry, rather than a close genealogical relationship . It's possible that such an adjustment affected your match.

[georgian1950]

Ancestry uses a proprietary program called Timber that eliminates or adjusts matches in "pile-up regions," that is regions of the genome where you have a large number of matches, which could be related to a shared physical characteristic or distant ancestry, rather than a close genealogical relationship . It's possible that such an adjustment affected your match.

I don't like hearing that. Some pileups have a close genealogical reason. I have an eighth great grandfather who I am related to at least four or five different ways. A great grandson of his appears to have been a prolific breeder. I'd be curious if Ancestry.com is throwing out some valid pileups in this case. Please note that I have not tested with Ancestry.com yet, but a lot of people besides me would have this ancestor in common. I've been thinking about testing myself and my mother with Ancestry, but if the company is going to throw out what they think are anomalous results, what is the point?

[jbarry6899]

This is Ancestry's rationale. They have a white paper, but you may need to have done DNA testing to see it.

link removed

[nicolam]

Ancestry uses a proprietary program called Timber that eliminates or adjusts matches in "pile-up regions," that is regions of the genome where you have a large number of matches, which could be related to a shared physical characteristic or distant ancestry, rather than a close genealogical relationship . It's possible that such an adjustment affected your match.

This might explain why two of my matches (2 generations of the same family) show up on FTDNA, 23andMe and Gedmatch but not at Ancestry.