00:02
Okay, so you put a lot of questions into this.
00:05
So i'm going to do my best to address all of them.
00:09
But i thought the best way to maybe address us was to just have a chat about all these different things that could eventually affect allele and gene frequencies.
00:20
So if we're not complying to all these variables that relate to hardy weinberg, right, we can, we'll talk about each of these individually and see what variables.
00:30
Is being affected.
00:32
So if you have a mutation, a mutation, right, means you're changing a gene sequence.
00:39
You're creating a new allele.
00:41
So obviously, if you have a mutation happening, you're creating a new allele.
00:46
That's going to affect allele frequencies, especially if it's beneficial, because that could be selected for and it could increase over time.
00:56
Migration flow.
00:58
There are also some typos.
01:00
Hold on.
01:00
We'll fix this.
01:03
Migration flow, right? if there's breeding between populations, maybe those other populations have different allele frequencies.
01:12
Some alleles are more common than others.
01:14
So if there's gene flow, this breeding could make certain alleles become more common in the following generations.
01:21
So yeah, that could then alter that hardy -weinberg equilibrium.
01:25
Small populations, really small populations.
01:29
If there are any breeding right between individuals, especially could very much alter those allele frequencies because if those populations are really small, anything those individuals do can significantly impact the overall population genetics.
01:46
With genetic drift, so the following two population bottleneck founder effect are all kind of related to genetic drift.
01:55
Genetic drift is this idea that gene frequencies change at random or due to chance.
02:01
And population bottleneck and founder effect are examples of random changes to allele frequencies.
02:09
So there's a population bottleneck that means there's some random event that suddenly reduces, significantly reduces the size of your populations.
02:19
So let's say you have a small population of snails and a tornado comes through and wipes out 70 % of those snails.
02:27
That's random, right? and at random, whatever snails are left are probably going to have a different allele frequency than that original population had.
02:36
You probably lost some alleles because of that random freak accident.
02:41
Right.
02:42
Also, population bottlenecks have happened due to hunting, right? the american bison, for example, was hunted nearly to extinction because rich guys thought it was fun to shoot them while traveling on planes across the united states.
02:56
Right? at random, whatever bison were killed, the ones that were left had different alleles.
03:04
So, yeah, that's an example of genetic drift.
03:08
Founder effect, right? a subset of the population is isolated, for whatever reason, from the original, at random, right? so the galapco's islands have probably come up in your class, maybe a marine iguanus.
03:23
So they're the result of founder effect.
03:25
As some of those, iguanas got isolated from the mainland and made on the galapagos and then via natural selection, right, of the remaining alleles.
03:38
We get the little weirdos we have today.
03:42
So, yeah, randomly what individuals are left over, again, can contribute to genetic drift.
03:49
Non -random mating, right? if certain individuals that happen to be closer together in space are more likely to mate.
03:57
Can potentially lead to certain alleles, theoretically, being more prevalent in following generations, increasing that allele frequency, or certain alleles being less frequent over time.
04:10
With harem breeding, right? there are oftentimes there's a male, sometimes a female, in control of lots of other individuals of the opposite sex.
04:20
So what this means is there are lots of females, but they're all reproducing with one, mostly one male.
04:27
Male...