Posted by I did a little experiment on the audience at FreeOK on Saturday (will be posted when The Thinking Atheist gets it up! Should be good quality, hes got all kinds of fancy stuff/tricks!).
*squint*
It wasnt really a matter of ‘will they get this?’, cause atheists/skeptics/freethinkers are smart.
It was more of ‘will they even like this?’
I *think* the answer to my experiment is “People kinda think this is cool!”
So Im gonna roll with it with you all– A series of posts connecting evolution (something a lot of skeptics are freaking amateur experts on) and immunology (scary) and the science of vaccines (scary). Connecting the new scary stuff to the stuff people are much more comfortable with, so skeptics can deal with anti-vaxers (and woo-ish immunology claims) as well as they handle Creationist claims.
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One evolutionary feature that Creationists hate is gene duplication and divergence. Start with one gene. Accidentally make two of those genes. One of those copies can keep doin what it do, the other copy is free to ‘explore’. Sometimes the duplicated gene explores itself right into a tiger trap. And sometimes it figures out how to do something new, cool, and useful.
That is basically Your Immune System. A collection of gene duplications which diverged and learned new tricks (or became pseudogenes, or diverged to the point they left your immune system to do something else entirely). Your immune system is a beautiful example of evolution in action, which kinda makes me think Creationists use ‘THE IMMUNE SYSTEM IS PERFECTLY DESIGNED!’ for the same reason they used ‘HIV IS PERFECTLY DESIGNED!’: they dont know jack about what they are talking about.
A really easy example of this are the antibody isotypes.
When you think ‘antibody’, you probably think of a ‘Y’-like structure, like this:
Generic ‘antibody’. It can bind to bacteria or viruses or cancer cells or microscopic space monkeys from the Krelm nebula with each of the two shorter ‘Y’ arms. Hurray!
Except… things arent that simple.
Lets say you have An Antibody that recognizes a specific little chunk of the chicken pox virus. Thanks to gene duplication and divergence, you have that antibody in lots of forms!
(image altered from here)
Its the same antibody (recognizes the same part of the same pathogen, with the same amino acid sequence), just with a different butt.
:-/
Each of these butts might kinda look the same, butt (heh) they all have their own specialties and deficiencies. Some do a bunch of jobs okay. Some do a few jobs REALLY well, butt (heh) suck at other jobs. And Im not sure why some of them exist outside of the fact we have no way of getting rid of wayward duplications that dont make themselves useful (Im looking at you, IgG4).
How do you get all of that antibody-butt variation?
For an example, just by chance alone, you have anti-chicken-pox antibodies in your body, before you were ever exposed to the chicken-pox virus or vaccine (another story for another day). Those basic anti-chicken-pox antibodies are actually that crazy ninja-star looking version, except sticking in the membranes of the cells that produce antibodies, B-cells!
When you are exposed to chicken-pox via a sick person or the vaccine, the B-cell that makes the anti-chicken-pox IgM gets messages via the antibody *in* its cell membrane, and starts to do things. Weird, unholy things. And I mean that very seriously– The B-cell starts to divide, and its babbys cut up their own DNA and paste it back together. This is an abomination. This should not happen (HELLO??? CANCER!!! We have a million safe-guards in our DNA to kill cells that start doing crazy stuff like CUT UP THEIR OWN DNA!!!), but in this case, it does, for a very good reason.
Because of gene duplication and divergence, there are lots of different antibody butt gene segments. When things get cut/pasted, this means some of the babby B-cells will make workhorse IgG antibodies. Some will make IgA antibodies, which can be secreted in your tears/saliva/mucus/etc, which will help protect you from getting chicken pox again if you ever share a drinking glass or a fork with a sick kid. And some will go off the deep end making IgE antibodies that are actually useful for something else entirely, but hey, the babby B-cells dont know that (Silly immune system! Chicken-pox isnt a parasitic worm!). Theyre just doing the best they can (youd be thanking them if you were exposed to a parasitic worm instead of chicken-pox).
So, thanks to evilution and evilutionary concepts like gene duplication and divergence, you can make the ‘same’ antibody lots of different ways. Because your immune system is mindless (its doesnt *know* you are infected with a *virus* and it needs to make antibodies good at attacking viruses), this ends up generating a lot of waste, like many evolved systems. But, because your immune system is mindless, it also means youve got a lot of bases covered when you are exposed to a new pathogen. And, the variants that are more helpful for a specific pathogen do survive better than the ones that arent overly useful (survival of the fittest w00t!)
Remember this stuff– more to come!
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