Tag Archive | DNA tools

New DNA Tools and Blog from a Scientist at Cornell

Much of the work to build tools and write articles to help testers with their DNA results has been done by citizen scientists, bloggers, computer programmers, and scientists from other fields like Andrew Millard (behind the WATO math). In an exciting development, Amy Williams, a computational biologist at Cornell University, has built a few DNA tools, with more to come, and started a blog at https://hapi-dna.org/blog/

Her blog article titled “How often do two relatives share DNA” is particularly interesting. It includes the beautiful chart shown below which is created from simulations. Click it to go to the actual page where you can mouse over the columns to get the detailed numeric breakdowns.

Chart of How Often 2 Relatives Share DNA from https://hapi-dna.org/2020/11/how-often-do-two-relatives-share-dna-2/

The other article on her blog has a detailed explanation of what a centiMorgan is, the measurement used for DNA segment sizes (click here). I usually recommend not worrying about the exact definition since it is a measure of the frequency of recombination rather than a physical length. It is important just to know that there is not a one-to-one relationship between the cM and the sizes shown in the chromosome browsers. On the those charts, the same cM amount looks smaller at the ends of chromosomes than it does in the middle because recombination is more active on the ends.

The final statement of that article is: “In an upcoming post, we’ll talk more about cM lengths of DNA and how recombination leads more distant relatives to share fewer segments that are also on average smaller than those that close relatives share.” Something to look forward to!

Now to take a look at the tools that are available there so far.

Of particular interest to adoptees is the maternal versus paternal predictor for half siblings or grandparents. I tried it out on a number of half sibling pairs who I have helped in the past.

Here is the prediction created for a brother and sister who share the same father but have different mothers, using the comparison of their segment data from 23andme:

However I discovered  number of minor usage issues when trying to use data from the different DNA testing sites.
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Great New DNA Tools in 2019

2019 was a great year for DNA. Many wonderful DNA tools were created by the testing companies as well as by a number of third parties. Throughout this article I will list my blog posts which discuss the tools from 2019.

I have found so many new cousins thanks to ThruLines at Ancestry plus the deployment of that to my DNA matches. My current process is to sort my matches by date and then filter for just 4th cousins or better (or 15cm or better) to catch new matches while they are still logging in and so might see my messages. Also once a week I check my matches that have common ancestors to see if any new ones have been connected in (since I note how people are related in the notes, anyone with blank notes is someone I have not yet seen the tree connection for):

MyHeritage‘s Theory of Family Relativity also makes it easier to find new cousins. Many of my Norwegian cousins have been found there. I even got a message from one this morning!

23andme may be finally trying to consider us genealogists. They added a build your tree from DNA feature (yet to be blogged about here) and connected to the FamilySearch tree. My wish for 2020 is that they combine those features!

My favorite new 3rd party tools in 2019 are DNA2tree, a game changer for unknown parentage cases, and the addition of trees to the automated clustering at Genetic affairs. I confess, I actually bought myself an iPad so I could use DNA2tree.

Automated clustering really took off in 2019 with GEDmatch, DNAgedcom, and MyHeritage all adding clustering.

2019 also saw the birth of a new public database for Y and mitochondrial results at https://www.mitoydna.org/ (to be reviewed soon).

I have yet to cover all the great new tools at DNApainter.com although I refer people to the online relationship calculator there regularly.

Other new tools sites that I need to review are Borland genetics tools and Your DNA Family

2019 has been a really great year for DNA tools!