What do antibiotic resistance, the many colors of butterflies, and the fact that life still
exists on this planet all have in common?
Genetic Diversity!
Genetic diversity is awesome!
It’s what allows us to all be a little different and to overcome any obstacle that comes our way!
But genetic diversity is also terrible!
It’s what leads to antibiotic resistance and part of what makes cancer so difficult to treat.
So let’s talk about genetic diversity and how it is super great… until it isn’t.
To understand how genetic diversity is both the best… and the worst,
we’ll need to break it down.
First we’ll look at what genetic diversity is,
Then we’ll look at how it can be really helpful,
and finally, we’ll see how it can be problematic.
So what is genetic diversity?
It's the little differences in DNA between members of the same species.
But to see what I mean, let's check out an example of
genetic diversity in a fictitious population of puffballs, and
for all you star trek nerds out there, we’ll call them tribbles.
We start with a little group of red tribbles and then those tribbles do what they do best
and they have babies! Now there are even more tribbles who are also red.
Then those tribbles have babies, and we get our first accidental mutation.
Now one of the babies is now blue instead of red, but it isn’t a big deal.
And the blue one can still have babies, so
the population continues to grow!
As it grows, more accidental mutations happen and now there are green, blue, and red tribbles.
This is genetic diversity.
So this is an example of genetic diversity in physical appearance, but
you can also have genetic changes in a population that don’t
affect what you look like.
Examples of this in humans are things like allergies, lactose intolerance, or whether
you think cilantro is a tasty herb or green soap.
I’m on team soap.
Now that we know what genetic diversity is, let’s look at how it can be a good thing.
Here’s our little tribble family from before, but
now they have a problem.
A new predator has moved into their area and it has an insatiable hunger for tribbles,
but it also has poor eyesight, so it can only see the red ones.
Because of this, all of the red tribbles are quickly eaten.
But because of diversity, there are some tribbles that survive the
predator and continue the species.
The bottom line here is that diversity is the way that populations overcome and adapt
to unexpected changes in their environment.
If all of the tribbles had continued to be red generation after generation, then when
that predator came along, they would have become extinct.
But while overcoming a predator was great in the case of the tribbles...
sometimes diversity can be a bad thing.
To show you what I mean, let’s imagine that instead of tribbles, this population is actually
made up of a deadly bacteria like Staphylococcus aureus which can cause blood infections, pneumonia,
and sepsis.
And instead of the predator that eats red tribbles, you have an antibiotic.
That antibiotic can kill all of the bacterial cells!
All of them except the black ones.
And just like the tribbles that were left alive when the predator came, the black
staph aureus cells left behind can still grow.
And if they can still grow, they can still cause disease, and your antibiotic doesn’t
work against them.
You’re in trouble.
And this is how diversity can be a bad thing.
Genetic diversity is all around us!
It’s what makes our world a beautiful place full of millions of different species!
It is the key to surviving changing conditions whether it is different temperatures, a new
predator, or a disappearing food source.
Diversity helps species survive which is sometimes the best, but other times… it’s not so great.
Thanks for watching this intro to diversity!
In part two of this genetic diversity series, I’m going to discuss a paper that talks about
genetic diversity in cancer.
As always, you can subscribe to my channel for videos every other Friday!
You can also follow me on facebook,
twitter, tumblr, or instagram. Or check out my website simplebiologist.com
See you next time!