DNA tools

One - to - One matches

It is useful to know that experts consider all matches, however short, "matches" but if you go below 3cM you will match most of the world and have almost no chance of finding out what the family tree connection will be. Generally under 7cM you are going to find the same problem. In these cases you need to have lots of other evidence, using your tree and theirs, surnames, geography and timelines in common too. Possibly if you have several people with a small size match you have several trees to check against. I personally do not use matches below 6-7cM or say 0.3% to contact others, unless there is a very good other reason or reasons. If you look at DNA charts you will soon see that third or fourth cousins have very little dna in common. Add to that generations older than you(-) or younger than you (+) the they are even more remote and smaller matches?)

Most websites provide a generation estimate - how many generations back is your common ancestor. Each provider is different but, ideally, you want to get a generation result, percentage match of DNA, how many pieces of DNA match (segments) and a family tree, as a starting point?.

Stepping Stones

One way to understand the generation estimate is to count the steps it takes to move from you to a known relative on the chart, like stepping stones?

Percentage DNA easily becomes small when moving across the chart from your position. The general 'autosomal' DNA test is useful for a maximum of 6-8 generations in perfect conditions. Something not always explained to potential purchasers of DNA kits.

DNA Cousins

Remember that a DNA match helps with trees but it is a two way street, using the tree and the DNA together? It is possible to match trees and then look for DNA confirmation. Wikitree allows users to put their kit details alongside their trees. Finding a useful tree then allows a DNA comparison to be made. On-site there is a facility to identify living descendants who could be available for testing.

Generally speaking, only contact your matches with a tree and some extra information that is relevant to you. I made a speculative leap with a small DNA match, no reason to make contact except her surnames list was 90% of mine. Turns out her ancestors lived within 1-2 km (about a mile) from mine. However, that is the exception rather than the rule and we still have not found a direct connection. :)

DNA CHART

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