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Archiver > GENEALOGY-DNA > 2011-01 > 1294767113


From: "Diana Gale Matthiesen" <>
Subject: Re: [DNA] How many realistic locations on the Y for SNPs?
Date: Tue, 11 Jan 2011 12:31:53 -0500
References: <CCC150916E8E4411AFE12370BBEEE726@PC> <001f01cbaeb0$4c9bff00$c2482dae@Ken1> <63975AE0-4907-4B8A-93D3-90B240793C8A@verizon.net> <002201cbaef0$22bda8b0$c2482dae@Ken1> <B62B7165-4267-4A0D-B8C4-7934D3BA2908@verizon.net> <008901cbaf4b$951943a0$c2482dae@Ken1> <F6FCB88D-57FC-4F12-8253-A278A9A3DFCE@verizon.net> <013201cbaf68$3c344830$c2482dae@Ken1> <52AE5437-01C7-424A-89DD-C36D016506FE@verizon.net> <019b01cbaf7c$82096390$c2482dae@Ken1> <CAC021EE-9E80-4226-9157-2A830A1A9A75@verizon.net> <021e01cbaf8f$643721f0$c2482dae@Ken1> <COL118-W42DB12E03AFE2E2BCDDD64A00D0@phx.gbl> <002601cbaf9c$5b51af30$c2482dae@Ken1> <COL118-W2972792AD05AE41FB629B6A00D0@phx.gbl> <AED10222-4F0C-4633-A86F-ED70B093F47E@verizon.net><1C284B4A-C38B-4654-B2A9-DB97BCAA4BA5@vizachero.com>
In-Reply-To: <1C284B4A-C38B-4654-B2A9-DB97BCAA4BA5@vizachero.com>


I didn't keep Jim's original message, so I can't place this response in the
thread where I would choose to, but consider this a response *to Jim*:

I do not agree with Vince. Every new mutation results in a *fork* in the
evolutionary path, the tine that continues unchanged and the tine that is
mutated. This is a cladogram:
http://www.geo.arizona.edu/Antevs/ecol438/hominid3.gif

It's a cladogram of species, not individual mutations, but the principle is the
same. Each new species is a *fork* in the evolutionary path, and both tines of
the fork persist on the cladogram whether the species dies out, or not. Events
in the present cannot change events in the past.

To Vince: let's do agree to disagree.

Diana

> From: Vincent Vizachero
> Sent: Tuesday, January 11, 2011 9:22 AM
>
> I think you need to be careful to specify what, precisely, you are talking
about.
>
> If you are talking about a haplogroup tree based on living men, the only
"forks" will
> happen when a man has two sons that both have living descendants. Most sons
will
> NOT produce a fork, simply because most men in that haplogroup tree had just
one son
> with a living descendant.
>
> Further most of "hidden" forks are not actually hidden. These "hidden" forks
do actually
> appear in the current tree, but as polytomies. But you are right that
identifying more
> SNPs will help us resolve those polytomies into bifurcations.
>
> However, note that if we were to only consider larger/older haplogroups (say,
more than
> 2,000 years old) that we may not need many more than the 1,000-2,000 Y-SNPs we
> already have.
>
> VV
>
>
> On Jan 11, 2011, at 7:05 AM, Jim Bartlett wrote:
>
> > It seems to me that with 25 million SNP sites, every son produces a
> > fork. If you are only using 700 SNP sites to build the tree, there
> > will be many "hidden" forks, which can't be resolved until more SNPs
> > are found.
>
>
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