Let me take a stab at this. I have thought some about this issue.
Some Background
Genes are a unit that are not self-replicators. They require a host of
complex machinery in order to replicate. This machinery is supplied by
the proteins present in a cell. The gene is basically the master copy for
some protein product that serves a purpose in the organism. Through a
host of complex interactions genes contribute to their own regulation as
well as the structure and function of cells. For some purposes genes may
be considered in isolation such as when you are trying to determine their
regulation and their direct effects. However when you want to consider
genes in an evolutionary context you will have to consider their role in
a system. Genes are maintained by selective pressures. The strength of
selective pressure can be deduced by the amount of conservation of
sequence identity between species.
Therefore genes can be considered as operating in an ecology similar to
the "ecology of memes" that has been previously mentioned in this list.
Genes may mutate, replicate, change roles, and die like ideas do in a
dynamic and complex web of interactions. The context of genes may impose
constraints similar to those imposed by the context in which an idea is
considered. Also the future possible functions of a gene are constrained
by its evolutionary history just as paradigms are constrained by their
intellectual heritage.
The virus analogy is also appealing because memes act like infectious
units. Like viruses memes can exist outside their host organism (as
books, pictures, or bits) and later infect a suitable host. An immune
system analogy also works for envisioning the resistance to memetic
infection. Viruses contain enough information that once they infect a
suitable host and evade the immune system they will proceed to produce
more infectious units. The similarity to evalangelical religions is
obvious.
The weakness of the viral analogy when compared to the genetic one is
that recombination of viruses is a rare event. Memetic recombination
is more prevalent except for those who have erected barriers to new
ideas. On second thought, this aspect may be more realistic than I had
believed?!?
Does this help?
Duane Hewitt