MITx Class on DNA is Free

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MITx offers a wide range of free, on-line, self-paced semester-long courses to anyone in the world. Coming up next week is Introduction to Biology – The Secret of Life. I’ve taken this course (actually twice). It’s taught by Professor Eric Lander – the founding director of the BROAD Institute and a principle leader of the Human Genome Project – and a fantastic instructor (his course is fun). This course is targeted at non-biology students. This is not about genealogy, it’s about DNA. Anecdote:  I was about halfway through the course, and one night my wife called out: “Jim, what are you doing – it’s 3 AM.” My reply: “I’m in a lab, folding proteins to capture a virus”.  If you are into DNA and Segment-ology, this is a great opportunity to get a firm grounding.  As a side note, I think MITx is a great undertaking and am a regular donor to that program. Free, world-wide MIT classes…

Here is a link: https://www.edx.org/learn/biology/massachusetts-institute-of-technology-introduction-to-biology-the-secret-of-life

Click on the short YouTube video… Enjoy.

[99D] Segment-ology: MITx Class on DNA is Free by Jim Bartlett 20250128

ProTools Part 25

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The Path Is Key

This may be an extension of my “genealogy sacrilege” outlook or rant.

But before I begin, to each their own – you get to choose your objectives.

My two main objectives are to get my genealogy right; and to get the Chromosome Map of segments from my Ancestors at each generation right. My objectives do not include finding all of the descendants of all of my Ancestors. However, I do think that documenting how my DNA Matches interrelate to me and each other is very helpful in achieving my two objectives – and this swells my Tree somewhat. I’m finding: Match paper trail paths (and ThruLines clues) that are impossible, given the DNA evidence; and DNA evidence that has revealed genealogy paths I never would have otherwise found (not just limited to breaking through brick walls).

So, a lot of work to do to document what will be over 10,000 Matches…  Time is precious…

When documenting DNA Matches and their line of descent from our MRCA to them, the “Path Is  Key”. Dotting all of the “i”s and crossing all the “t”s is NOT! The DNA segments do not “know” their hosts’ names (or dates, or places), just that the segments are passed along. We genealogists document what we can about each of these Match ancestor DNA hosts. It helps us keep track – in time and place. But how much effort do we need to put into documenting our Matches’ lines? My opinion is: not much! We need to be sure of the path. We don’t need to know the full names, or pet names, or titles. It’s nice to know the birth/death years, but how much digging should we do to find the complete birth date or place? What do we do when several different descendants insist on different given names … I could go on and on, but I’ve decided it’s not my job to adjudicate their family “wars” – my objective is to be clear of the path.

Therefore, I’m now using terms like Pvt, Unknown, GUESS, sibling of XYZ, etc. to describe Match Ancestors – particularly those close to the Match.I don’t really care about their parent’s or grandparent’s names or genealogy info – just the path that must exist for a DNA segment. [NB: proving a specific genealogy-DNA link is a separate issue; a potential path is not a proven path.]

I am still documenting the child and grandchild of the MRCA (given name and birth year at least). But, IMO, the further down the path from the MRCA to the Match, the less precise this info needs to be. The Key Is the Path. I don’t want to introduce incorrect info, so I’m introducing “other” terms in the name field when it is unclear, in debate, or might take days to research and resolve. I note the “path” that has to be and move on.This allows me to get as many DNA Matches as possible into the spreadsheet. Then the interrelationships can be better evaluated.

SUMMARY:  Don’t worry about “fully” documenting the MRCA-to-Match path; just that the path does exist, and no incorrect info is introduced (unless your Tree is private). And, of course, it’s up to your own judgment as to if/how much of this recommendation to follow. My plan is to get as many Matches as possible into MRCA family groups in a spreadsheet, and then study the interrelationships with ProTools. Get Matches in my Tree and my Common Ancestor spreadsheet, but “do no harm”.

[22DG] Segment-ology: ProTools 25 – The Path Is Key by Jim Bartlett 20250222

ProTools Part 24

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Small Segment Stats

Ancestry DNA Matches who share 6-7cM and have a known MRCA with me: 1,160.

Total Ancestry DNA Matches at any cM level: 7450.

About 15% of my DNA Matches with a known MRCA share only 6-7cM.

This is NOT a statement linking DNA and Ancestors.

This IS a statement about the many true cousins we will not see in our Match lists because the current threshold at AncestryDNA is 8cM.

I’m glad I Dotted and saved some of my 6-7cM Matches when Ancestry made the threshold change – it was a fraction of the total. I wish I’d have saved them all…

To end on a higher note – I still have 2,600 other 6-7cM Matches to work with – many of them are being determined as close cousins to known MRCA Matches by using ProTools.

[22DF] Segment-ology: ProTools Part 24 – Small Segment Stats by Jim Bartlett 20250221