GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2008-10 >
1224068007 From: "Dienekes Pontikos" <> Subject: Re: [DNA] What
is a clade? Date: Wed, 15 Oct 2008 13:53:27 +0300 An haplotype-
determined clade specification is impossible A clade
specification is valid if it can identify Y chromosomes that
share common descent _at the exclusion_ of other Y chromosomes.
Suppose you have devised a test T to determine whether a
Y-chromosome belongs to the clade or not. Suppose that the clade
founder F lived G generations ago. The test T, should be
powerful enough to identify members of the clade despite
G-generations worth of mutations. But, by symmetry, this test
would also (erroneously) identify G-generations worth of
ancestors of F as members of the clade. On Tue, Oct 14, 2008 at
5:13 PM, Ken Nordtvedt <> wrote: > "Haplogroup" has been
enlisted as the name for a clade identified by its members
sharing some up-til-now basically unique mutational states, most
often ydna or mtdna SNP mutations. This is rather straight