Archiver > GENEALOGY-DNA > 2012-02 > 1329890210

From: Obed W Odom <>
Subject: [DNA] Clades versus clusters
Date: Tue, 21 Feb 2012 23:56:50 -0600

In the recent controversy, notably between Diana and Ken, about whether
to use the term "clade" or "cluster", I think both are probably right,
but Diana, using SNP's to define clades, is on a firmer footing than
Ken, using clusters of STRs to define clades. If a clade is defined as a
common ancestor and all of his descendants, then I think a shared SNP
(in context) is a more certain indicator of a common ancestor than is
membership in an STR cluster. However, to some degree of accuracy both
define clades, and the clade defined by the cluster of STRs would be a
nested clade (or subclade) within the clade defined by an SNP. For
example, in the case of haplogroup I1, I1-AS2 (if it is not just the
remnant maintaining the clade founder's STR pattern) would be a nested
clade within the clade defined by SNPs Z138 and Z139. Then I, as an
I1-AS-generic who is also Z138+ and Z139+, would be a member of the
clade defined by these SNPs but not of the nested clade defined by the
STR cluster.

A diagram drawn by personnel at UC Berkeley, which may add clarity to
the meaning of clade, can be seen at the following link:

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