Re: data modeling genes and alleles... help!

List,

I have a data modeling problem. That much, I know. The question is how do I
model this? (Below.)

I'm making a database which will store pseudo-genetic data. It's a basic
many-to-many setup::

   create table person(
       name varchar(32) primary key
   );
   create table gene(
       name varchar(32) primary key
   );
   create table person_gene(
       person varchar(32) references person(name),
       gene varchar(32) references gene(name)
   );

Great. This is important as I need to be able to ask questions like "who
carries gene 'x'?" as well as "what genes does person 'y' carry?" But then
things get thorny...

I also need to store the properties of the individual genes (the alleles). This
is akin to an instance of one of the many gene classes in my application code.
So I make more tables::

   create table hair(
       id serial primary key,
       density float,
       thickness float
   );
   create table eye(
       id serial primary key,
       pupil_type int
   );

How do I store a reference to this data? I'd add a column to the person_gene
table, but it points to what? I can't reference a column name because they're
all stored in different tables. I also can't store them in the same table, as
they all store different data. Do I store the *table name* itself in a column
of the gene_table? (Smells like a klude.)