Dear Tim, A little earlier you wrote "There is only a 12.5% probability that any one DNA segment that my parents have will not have been inherited by one of my brothers or me." You have more than one sibling, and I gather Karen does too. What would the probability for just two children (since I have only one sibling, and we didn't test my father before he died)? Or can I actually tell the true percentage by looking at 23andMe's chart of our half-and-full identical areas? Karla On Sun, Oct 20, 2013 at 1:50 AM, Tim Janzen <tjanzen@comcast.net> wrote: > Dear Karen, > You should not only test "one" of your siblings, you should test all of > your > siblings if your mom is dead. You will never regret doing that. If you > have 10 siblings, then you might want to test 4 or 5 to begin with since > there will be diminishing returns the more siblings you test. > Tim > >

Karla Each child gets exactly 1/2 of each parent's atDNA. Each parent has 2 of each chromosome and through recombination makes 1 that is passed to each child. A second child also has 1/2 of each parent's atDNA - some of this overlaps the first child; and some is part of the atDNA that the first child didn't get from the parents. On average, you and each sibling will overlap 50%; and your sibling will get half of the atDNA from your parents that you didn't get. So between you, on average, you will get 75% (3/4) of your parent's atDNA. So each of your parent's atDNA will go: 25% HIR to you; 25% Full IR to you and a sibling; 25% HIR to your sibling; and the final 25% to neither of you - lost forever to your children A third child would, on average, get 1/2 of the final 25% above; leaving 12.5% (1/8) which no one got. A forth child would get about 1/2 of this 1/8; leaving 1/16 that no child got. Etc. As always, your results may vary. And yes, you can see your own actuals at 23andMe and at GEDmatch. Jim - Sent from my iPhone - FaceTime! On Oct 20, 2013, at 10:28 AM, Karla Huebner <calypsospots@gmail.com> wrote: > Dear Tim, > > A little earlier you wrote "There is only a 12.5% probability that any one > DNA segment that my parents have will not have been inherited by one of my > brothers or me." You have more than one sibling, and I gather Karen does > too. > > What would the probability for just two children (since I have only one > sibling, and we didn't test my father before he died)? Or can I actually > tell the true percentage by looking at 23andMe's chart of our half-and-full > identical areas? > > Karla

On Oct 20, 2013, at 12:36 PM, Jim Bartlett wrote: > Karla > > Each child gets exactly 1/2 of each parent's atDNA. Each parent has 2 of each chromosome and through recombination makes 1 that is passed to each child. A second child also has 1/2 of each parent's atDNA - some of this overlaps the first child; and some is part of the atDNA that the first child didn't get from the parents. On average, you and each sibling will overlap 50%; and your sibling will get half of the atDNA from your parents that you didn't get. So between you, on average, you will get 75% (3/4) of your parent's atDNA. So each of your parent's atDNA will go: 25% HIR to you; 25% Full IR to you and a sibling; 25% HIR to your sibling; and the final 25% to neither of you - lost forever to your children > > A third child would, on average, get 1/2 of the final 25% above; leaving 12.5% (1/8) which no one got. A forth child would get about 1/2 of this 1/8; leaving 1/16 that no child got. Etc. I just ran the numbers on my three children, and this prediction is right on target. 10.1% of my husband's DNA was not inherited by any of them, and 15.5% of mine.

Dear Karla, Jim Bartlett gave a very nice explanation to your question earlier today. I thought I would give you the statistics as to what percentage of your parents' DNA you can expect to capture if you test a varying number of the children of those parents as follows: 1 50 2 75 3 87.5 4 93.75 5 96.875 6 98.4375 7 99.21875 8 99.609375 9 99.8046875 10 99.90234375 11 99.95117188 12 99.97558594 13 99.98779297 14 99.99389648 15 99.99694824 16 99.99847412 17 99.99923706 18 99.99961853 19 99.99980927 20 99.99990463 I can run estimates for couples who have more than 20 children if necessary! Sincerely, Tim Janzen -----Original Message----- From: autosomal-dna-bounces@rootsweb.com [mailto:autosomal-dna-bounces@rootsweb.com] On Behalf Of Karla Huebner Sent: Sunday, October 20, 2013 7:28 AM To: autosomal-dna@rootsweb.com Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them What would the probability for just two children (since I have only one sibling, and we didn't test my father before he died)? Or can I actually tell the true percentage by looking at 23andMe's chart of our half-and-full identical areas? Karla