Seeking Gene/Protein Family with best-characterized subfamilies

[Georg Fuellen]

[This is a courtesy copy of a message which was also posted to the
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Dear All,

For phylogenetic studies, I'm looking or a gene/protein family for which --

1 There are subfamilies and sub-subfamilies, and for at least some
  of these, sites are known that feature an amino acid typical
  for the (sub-)subfamily.

2 There are at least some subfamilies of biomedical importance.

In other words, which family features the largest, richest, best-recorded 
and best-accessible knowledge-base about inheritance relationships
and (functionally) important sites ?

Who can help? Alternatively, I wonder:
Which database may answer my question in an optimal way ?

I'd be grateful for any advice,
Georg Fuellen

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