John Richard Seavitt wrote:
Does evolution play a significant role?
>snip<"it hasn't been selected against. Yet."
I gotta disagree with that blanket statement, without knowledge I
would agree that the B cell form did evolve from a something previous,
but there is no indication that it was selected for or not selected
against. One could argue that a non-allelic exclusion model was tried
and didn't work but that is only speculation. I maybe allelic
exclusion is normal and non-exclusion has been selected for fecundity
or whatever? definately the receptor story is weak, any given cell has
multiple receptors or which a portion are always ligated and the cells
discriminate readily between receptor signals so i don't think it would
be impossible for 2 ag receptors to work independently. they could be
regulated by different transcription factors. Heck the the worst
scenario I can think of would be an increase in auto-antibodies if both
ab were made.
is it a literal why or a figurative why?
MarkH.
