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Ancestry Matches 7cM and less

Discussion in 'DNA Questions and Answers' started by Andrew Lloyd, Jul 15, 2020.

  1. Andrew Lloyd

    Andrew Lloyd LostCousins Star

    I note from the latest newsletter that Ancestry are going to remove matches at 6cM and 7cM. My apologies if someone has already started a discussion on this but I cant see it yet.
    I also note that in the newsletter, Peter says he will lose 8,000 of his 24,000 matches - I just wonder if this is an optimistic estimate?
    I know that of my 46,000 matches, about 15,000 are at the 7cM strength and about and 11,000 are at the 6cM strength, so I will be losing about 56% of my matches. There are very similar statistics for the other 3 DNA results I manage.
    I also wonder if Ancestry will be setting the limit at 8.000 cM or 7.500 cM because 8cM currently captures matches between 7.500 cM and 8.499 cM so if they set it at 8.000 cM then about half of the 8cM matches will be lost also (accounting for another 9% of matches).
    Currently the limit is at 6.000 cM which is why the 6cM figure is less than the 7cM figure (ones between 5.500 and 6.000 are not captured)
     
  2. Bryman

    Bryman LostCousins Megastar

    Thank you Peter for the warning in the latest newsletter. That has prompted me to look again at my identified common ancestors and I have found a new match that is a 3rd cousin. Well actually my father's 3rd cousin, so once removed to me (ie 3C1R). Interestingly, we share only 6cM in 1 segment and I have verified our connection easily via census and BMD records due to the small number of generations involved. This shows how bad the Ancestry decision can be, particularly in the light of so many new tests now being evaluated. How many other cousins will be missed when matches at 6cM and 7cM are ignored? Would it not be better to leave them included but suitably labelled as dubious?

    By the way, how can one determine the number of matches identified at each cM level? Am I missing something obvious?
     
  3. Andrew Lloyd

    Andrew Lloyd LostCousins Star

    No you are not missing something obvious. I used something called Shared Clustering to obtain a spreadsheet of my Ancestry matches. This software has now been disabled as it is too intensive use of Ancestry resources.
     
  4. Helen7

    Helen7 LostCousins Superstar

    I too have a verified 3rd cousin who only shares 7 cM with me (plus his 2 children, also with similar shared DNA). I had identified them some time ago, mainly because we share the same surname. I easily traced our common ancestry and we've been in touch to verify the link too. I was surprised how little DNA we shared, though I know sharing any DNA at all isn't guaranteed beyond 2nd cousins.

    So it's not just distant cousins who will be lost from our match lists when the new 8 cM minimum is imposed - or they might still be distant but very useful in knocking down brick walls. Thanks for the warning, Peter. I am in the process of going through my and my husbands 6-7 cM matches - concentrating on those flagged with 'Common Ancestor' and those with key surnames - adding a note and/or a colour coding, to hopefully minimise the losses.
     
  5. Helen7

    Helen7 LostCousins Superstar

    Perhaps I should be checking the 8 cM matches as well as the 6-7 cM ones?
     
  6. anniefb18

    anniefb18 New Member

     
  7. anniefb18

    anniefb18 New Member

    Is there any quick way of adding all the ones that will disappear to a group to save them, or do we have to do it individually?!
     
  8. canadianbeth

    canadianbeth LostCousins Member

    I have 97 people listed as common ancestors. Twenty of them have cM of 8 or less and I have written notes as to whom they are connected and their degree of cousinship, so they should not, hopefully, disappear. However, since learning of the complete contradictory information regarding one branch, (between Ancestry and MyHeritage) I am no longer sure if any of the matches are correct, other than the one listed first, and possibly some of the ones connecting to Joyce. Definitely not the Riches/Moss branch, since that is the suspect one.
     
  9. Andrew Lloyd

    Andrew Lloyd LostCousins Star

    I am not aware of a method of bulk loading to a group, but you can reduce the keystrokes required by getting the required matches into a list, thus not necessitating the need to navigate to different pages. For example, use the Custom centimorgan range set to 6cM to 7cM (or 8cM) in the Shared DNA menu and then use a search criteria for example to select a particular surname.
     
    • Thanks! Thanks! x 1
  10. Winksetter

    Winksetter LostCousins Member

    Hi, I am horrified by this change. I looked at my matches and immediately came across quite a few matches in the 6 to 7cM range that Ancestry had them selves identified as having common ancestors with me. I also have lots of other resolved matches in this band. Without these matches Ancestry will have minimal value to me. The most useful matches to me are in this category and have led to the best discoveries. i would recommend all Ancestry DNA users to download their results and upload to other sites. Gedmatch and Familytree dna are obvious choices. I also did Myheritage when free uploads were available, I have lots of matches from this site and from the other sites, none of which have so far Come up on Ancestry. Myheritage is good because Ancestry is not sold in all countries where Myheritage is. The way Ancestry is now I will not be using it much, already the tools available are very much primitive compared to the other sites. It may have most users but.....
     
  11. Kiwi Colin

    Kiwi Colin LostCousins Member

    Thank you for the heads up Peter. My first premise is that DNA connectivity is so very random. This is why I feel that ancestry.com’s decision you outlined is not in the best interests of customers. Their refusal to provide a chromosome browser and other tools does not allow us to investigate properly potential relationships we find independently, but tie us completely to the formulated pathways they determine. As users and customers I feel we should have the choice to determine which match is relevant and which match is not, because we are the ones that know our ancestors and cousins far more intimately than the computer model they use.
    I have numerically fewer matches than many other people tested. Some lines on my tree are mainly devoid of matches. This I feel is mainly due to geographical bias and hence numbers tested. Thus I am regularly working in the low cM area of matching and have found connections with proper documented trees many times at the 6 to 8 cM range. My research would be so much weaker in effect without having access to matches they now want to withhold. Thrulines is a good tool but does not take into account the randomness and extension that can be achieved in our matches. I found connection back to 7 x g grandparents lately with several matches being involved, not just the one.
    Ancestry may tell us there are work arounds to enable us to retain some matches, but that is only in the now and doesn’t take into effect any new discoveries in the future. A Red Herring entirely!
    This proposal is not in the best interests of Users and as such we need to be able to make the relevant decisions that effect the research in our trees not the Monolith that is Ancestry.
     
  12. jorghes

    jorghes LostCousins Superstar

    One of the filter settings at the top of your DNA list is for "shared DNA", it states that, for example, my mother's results have some 48,000 matches between 6cM and 20cM.
    You can then choose to filter the list by a custom amount of cMs, so you could filter the list just to show those with the lower lists.

    The system allows you to use multiple filters, so discovering which of your 6-8cM matches has a Common Ancestor is as simple as clicking on that filter.

    (Conversely, my grandmother's results have over 92,000 matches between 6-20cM)
     
  13. Bryman

    Bryman LostCousins Megastar

    Thanks for your suggestion jorghes but the "shared DNA" button only displays counts for 3 predetermined categories . . .
    All matches (x)
    Close matches (y) . . . ie between 20cM and 3490cM of shared DNA
    Distant matches (z) . . . ie between 6cM and 20cM of shared DNA
    There is no count for custom ranges and the values must be given in integers, so not possible to specify 6.1 - 6.2, etc.
    In my case, the value for 'z' is about 175 times greater than that of 'y' and it is super tedious to scroll through matches (and stay awake) for those sharing 6cM and 7cM.
     
  14. Pauline

    Pauline LostCousins Superstar

    Another tip to speed things up a bit is, having got the list you want, start at the bottom of that list and work upwards when clicking to add matches to a group.

    Although it may vary according to browser, generally when you click 'Add/edit groups' the dialogue box doesn't go away until you click off it. By working upwards you can do this by clicking on 'Add/edit groups' on the next match up, whereas if you are working downwards the next match is obscured by the dialogue box, requiring two clicks each time instead of just one.
     
    • Good tip Good tip x 2
  15. Pauline

    Pauline LostCousins Superstar

    Like most people, I have quite a few confirmed cousins with whom I share only 6 or 7 cM. Fortunately my practice has long been to add people to a group as soon as I have identified them and mostly, albeit not invariably, to add a brief note at the same time. So everyone in my common ancestor list is already in a group, as is anyone identified via searches etc.

    I haven't tried to work out what proportion of my matches fall into the 6-8 cM range but around 20% of my common ancestor matches are in that range. I have about 150 common ancestor matches in all, and for 6 of these I know that the supposed linking ancestor is spurious - that is, I may be genuinely related to that match somehow but not via the "common ancestor" suggested.

    4 of the spurious matches are in the 6-8 cM range, so deleting all matches in that range would remove over 6 times as many genuine (or probably genuine) cousins as spurious ones from the common ancestor list.
     
  16. Bob Spiers

    Bob Spiers LostCousins Superstar

    Yes good luck with MyHeritage, you are likely to find a match to the Queen of Sheba and other biblical and non-biblical characters from History, especially if their attempts at DNA matching are anything like results gained by non DNA matching found as a subscribed member. If (as Peter announced in his Newsletter) Ancestry's DNA user base of 18 Million -more than the others combined - does not impress, and you hang your hat on the fact MH sells in all countries, then you are (to be very British) batting on a 'sticky wicket'.
     
  17. Bryman

    Bryman LostCousins Megastar

    A nice idea but with thousands of matches in the 6cM and 7cM regi0n, coupled with the slow display of matches by Ancestry, getting to the end of the list can take 'forever'. Also, I often find that Ancestry restarts the list when barely 'half' way through. I suspect that Ancestry is proposing to remove the matches with less shared DNA because the programs used just cannot cope, rather than the claimed improvement of match quality.
     
  18. peter

    peter Administrator Staff Member

    For researchers with ancestors who mostly originated from the British Isles Ancestry is streets ahead of every other site.

    Ancestry are making this change for the benefit of users, and as anyone who has been following the strategies in my Masterclass will have already added notes to DNA matches that are of potential interest, most LostCousins members won't be adversely impacted.
     
  19. Pauline

    Pauline LostCousins Superstar

    Yes, I suspect all ideas to speed things up won't help much when dealing with thousand of matches but with a defined list of a hundred or so, every little helps.
     
  20. Bob Spiers

    Bob Spiers LostCousins Superstar

    You can speed things up by creating custom groups based on (say) major surnames + locations which although this can still present a daunting list, not nearly so much as without filters of this kind.

    But I agree with your reasoning why Ancestry have taken this decision, that their system cannot cope rather than improving match quality.

    Edit: Despite reading that Peter claims they did it as a benefit to users. The benefit as in all commercial changes has to be to the originator, first and foremost...but then I am just cynical on such matters).
     
    Last edited: Jul 16, 2020

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