But not, an important part here is that once we have a good 17cM ancestral segment off a great 4G grandparent, a 5C is just planning express part of by using us
-Gen cuatro: Ancestral avenues (averaging 21 cM) out of your 16 3G grandparents is actually spread-over on 159 avenues. So you carry out look for, on average, an ancestral section off for every 3G grandparent in around other 10 avenues spread-over this new chromosomes in that genome. The mutual places do mediocre 6.6cM, but another way to consider this would be the fact more or less 50 % of ones could be more than 7cM. Although not, feel means that a somewhat small fraction in our Fits is actually 4C and you will closer friends. So are there not many like Fits to cover the avenues within our genome.
-Gen 5: All of our thirty two 4G grand-parents however provide us with rather high 17cM ancestral markets (on average) dispersed over 193 locations. We could possibly still find the majority of the 4G grandparents in the several markets. The 5C Suits just share, typically, step 
1.7cM. So only some of them, into tails of your shipment shape, often share 7cM or even more. New counterbalance would be the fact you will find unnecessary 5Cs, that individuals however get plenty of IBD suits together with them. It would get several 5Cs, for each that have an excellent 7-10cM portion, partially overlapping our own ancestral part, to help you “cover” our 17cM ancestral part. In practice we often rating 5C Matches with a lot more than mediocre areas, but usually not as huge as 17cM.
-Gen six: Our 64 5G grandparents solution down ancestral avenues so you’re able to us one mediocre regarding 15cM. They citation this type of right down to on average 227 markets; each 5G grandparent often solution off DNA to 3 or 4 some other areas, an average of. Possibly several of the 5G grand-parents won’t have DNA one to reaches all of us at all, while others my solution off 5 or even more places – around, it usually averages away. At this height a lot of all of our Fits will be 6C, offer and take a little. A beneficial 6C, typically, simply offers 0.4cM regarding DNA with us. But you’ll find enough time tails during these shipments shape, And then we features plenty of 6Cs. As a result, that people have of many 6C that do express IBD areas with us over 7cM. Yes, the probability of a specific 6C mutual phase is just one forth the probability of a 5C, but you will find so much more 6C than simply 5C, we really have more Matches having 6C. It indicates far more 6C Matches are around which have a provided section more than 7cM, than just you can find for 5C. Again, it can normally get a few of these to “cover” and you will ancestral section (an excellent TG).
-Gen 8: Bypassing a manufacturing towards 256 7G grand-parents. Up until now you can find normally 295 segments, or around that section each 7G grandparent. Demonstrably by this big date a few of the 7G grandparents do not subscribe to your DNA, and some 7G grandparents sign up to multiple ancestral areas. Your own ancestral areas are in the brand new eleven-12cM assortment, an average of. And despite the fact that 8Cs only display a small amount from DNA typically, there may be of a lot 8C that have mutual locations over a great 7cM endurance.
Although same data is valid playing with 23andMe and you can FTDNA analysis – both report of several Fits, both claim a little IBS rates (below 5%), and also by their particular quotes, a lot of our Matches are beyond 4C
All through this analysis, the number of ancestral segments has increased by a constant 34 with each generation; the average segment size starts off large and decreases with each generation, but even after 13 generation, the average ancestral segment is still over 7cM; the number of ancestors continues to double with each generation (and at some point duplicates will start to appear, but as I’ve outlined in Endogamy I and II, each duplicate really acts like a separate ancestor); and the average size of shared segments decreases by a factor of 4 with each generation, but we still see many Matches with shared segments over 7cM. To expand on this last point, I have over 10,400 “phased” Matches at AncestryDNA, with all the pile-ups and IBS already culled out. About 400 of these Matches are 4C or closer, leaving over 10,000 Matches in the 5C or more distant range. The distribution of these is spread out among 5C, 6C, 7C, 8C, etc. It is, so far, unclear how far back these go, but clearly there are many in the 5C-8C range. And AncestryDNA claims their “phasing” program has less than a 1% error rate. So 99% of these are IBD shared segments, probably most in the 6C-to-8C range. To my thinking, this means most of them must line up somewhere on our chromosomes. If we assume half, or 5,000, of these Matches are for each genome, on average, then these 5,000 Matches must be on 300 to 400 of my ancestral segments – or over 10 Matches in the 5C-8C range on every segment, on average. Some ancestral segments (TGs) may have more, some may have less, but the 5,000 IBD Matches have to go somewhere. I’ve picked on AncestryDNA here, because they poo-poo Triangulation (I think they don’t really understand it), and because they have equations that some have used to argue that we cannot have multiple 4C or above in TGs. All of these IBD Matches have to be on our chromosomes somewhere. And, in 14 months (by my estimation), we will have twice as many Matches as we have now – we’ll have over 20 Matches per ancestral segment (TG)!
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