The Trouble with Genetic Diversity – Part 1

The Trouble with Genetic Diversity – Part 1


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!

2 thoughts on “The Trouble with Genetic Diversity – Part 1”

  1. I really enjoy watching your videos! Part of the reason is probably because your voice is so soothing ๐Ÿ˜‚

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