Mascot
Rusty is a 22 year old llama. He is on a special ration
and we should not feed him.
Rusty lives across the parking lot from our lab in the Stevenson Center. He is not
really ours at all. But we like him and he seems to like
us. His hobbies are grazing and expectoration.
So why the heck would a lab that studies sharks and frogs want a
llama as a mascot? Especially one with Rusty's manic
temperment? While his terrific posture and handsome eyes
help, the real answer lies in his humoral immune system!
Antibodies are made by B cells and they are comprised of heavy
and light chains... usually! In a beautiful example
of homoplasy, both cartilaginous fish and camelids
have evolved antibodies that use pairs of heavy chains, but with no
light chains. These two very divergent groups of vertebrates
both convergently arrived at this antibody innovation in their
evolution. The stability and single-variable domian paratopes
of these antibodies are being exploited for diverse
applications. The sharks appear to go a step further and use
a relative of the single chain variable on some T cells, we call this
NARTCR.
(No, even this
wonderful molecule does not protect sharks from cancer.)
Incredibly, early mammalian lineages (marsupials and monotremes) use a similar T cell
receptor usually with two variable domains as well, yet from a
different locus. More gorgeous convergent evolution
demonstrating the diverse paths that have arrived
at similar contrivances in lymphocyte
receptor repertoires.
So if in the area, go visit this nice camelid. He has a a
repertoire of antibody structures that most of us bony
Teleostomi can only dream of! Call his name and he'll come
running... but if the ears drop back you might want to take
cover.