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General => Ancestral Family Tree DNA Testing => Topic started by: dtcoulson on Sunday 26 January 25 01:20 GMT (UK)

Title: DNA spreadsheet models and what they show
Post by: dtcoulson on Sunday 26 January 25 01:20 GMT (UK)
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Last year I became interested in certain questions to do with DNA inheritance and realised that a good way to solve those problems was to set up my own mathematical model in a spreadsheet. This led to more questions and eventually I had three kinds of spreadsheet model addressing different questions in inheritance. I thought this would be worth sharing so I fleshed it out into a full tutorial on DNA matching and what to expect when you look at the centimorgan values associated with distant cousins.

Take a look if you are interested.

https://docs.google.com/presentation/d/1u3PkMVIF19BjXmGxi2tWL7TiPK0JU4pG/edit?usp=sharing&ouid=103690850444052751162&rtpof=true&sd=true

-DC

Title: Re: DNA spreadsheet models and what they show
Post by: Ruskie on Sunday 26 January 25 05:39 GMT (UK)
I’ve only had a quick look so far, but you’ve certainly put a lot of work into this and it looks very professional. I’m sure it will be useful for many. Well done, and thanks for sharing.  :)
Title: Re: DNA spreadsheet models and what they show
Post by: scotmum on Sunday 26 January 25 09:15 GMT (UK)
I applaud the work that has obviously gone into this.

I think your statement:

Quote
I am a hobbyist who finds it difficult to let go once my curiosity is aroused

could equally apply to a great many of us Rootschat members.

 ;D
Title: Re: DNA spreadsheet models and what they show
Post by: pandacub on Sunday 26 January 25 09:45 GMT (UK)
Thanks for sharing this.  You have clearly put a lot of work into it and it looks very useful. 
Title: Re: DNA spreadsheet models and what they show
Post by: julianb on Sunday 26 January 25 10:33 GMT (UK)
Quote
I thought this would be worth sharing so I fleshed it out into a full tutorial on DNA matching and what to expect when you look at the centimorgan values associated with distant cousins.

Still working through it between Sunday morning chores  ::)

I've tried to explain the source of an individual's DNA by comparing it to lottery balls, but I think your deck of cards is much better!  Thank you for that  8)
Title: Re: DNA spreadsheet models and what they show
Post by: Biggles50 on Sunday 26 January 25 11:06 GMT (UK)
Most Excellent.
Title: Re: DNA spreadsheet models and what they show
Post by: KitCarson on Sunday 26 January 25 12:14 GMT (UK)
Hi DC,  Thanks for sharing.

Kit
Title: Re: DNA spreadsheet models and what they show
Post by: SouthseaSteel on Sunday 26 January 25 15:05 GMT (UK)

Most excellent. thank you for sharing.  In a world awash with expertise, its good to see some wisdom and common sense too.
Title: Re: DNA spreadsheet models and what they show
Post by: julianb on Sunday 26 January 25 18:47 GMT (UK)
Quote
Still working through it between Sunday morning chores  ::)

I've tried to explain the source of an individual's DNA by comparing it to lottery balls, but I think your deck of cards is much better!  Thank you for that  8)

Chores done!

It's interesting to see a theoretical breakdown on how DNA might pass through the generations, because the data drawn from test results on eg Ancestry is distorted by being dominated by people who volunteered to take part!

I've set up matches spreadsheets (relationship matrix) for certain family groups so I think I'm going to explore rearranging these in the way you have done. Thank you for that practical tool

It did strike me that your endogamy calculations might be impacted by higher levels of infant mortality and life expectancy in victorian times and earlier, thus reducing the overall numbers passing DNA on.  To a degree is that probably academic because it's value is as an illustration of scale rather than an underlying rule of DNA?

And finally the cake cutting model, and it's cupcake enhancement, is again a very good explanation to kick my lottery balls even further into touch.  Great work, sir  :)
Title: Re: DNA spreadsheet models and what they show
Post by: dtcoulson on Thursday 06 February 25 03:14 GMT (UK)
Thanks for the positive feedback folks.
Title: Re: DNA spreadsheet models and what they show
Post by: dtcoulson on Friday 07 February 25 04:38 GMT (UK)
I saw that some of the graphics in my DNA document did not translate well to the online presentation software so I have reformed the graphics slightly and re-uploaded, here.

https://docs.google.com/presentation/d/14Kenyuvyp41eWphtvM6ZRn1POkymB8MD/edit?usp=sharing&ouid=103690850444052751162&rtpof=true&sd=true

-DC