Difference between Genetic Drift and Gene Flow?

[Impulse155]

So if gene flow is the introduction/removal of alleles from a population when individuals leave/enter a population
and genetic drift is a random increase/decrease of allele by chance. Often occurs by making apopulation smaller, than what is the difference? Is it just that gene flow is specifically by emigration where genetic drift can be from anything?

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[jgdg]

someone correct me if I'm wrong but this is what I think of:

Gene flow is when you introduce or remove alleles because of individuals enter or leave population (Think: alleles flowing in and out)

Genetic drift is the RANDOM change in allele frequency in a population. The Founder effect ("founder" of population has uncommon allele that is transferred throughout population) and bottleneck population (natural disaster or something like that wipes out a big chunk of population so few remain) are examples of genetic drift. So notice how in founder effect and bottleneck population, the populations are tiny so if there is a random change in allele frequency, it is really prominent in the population.

I hope this makes sense. I gathered the above info from what i have learned from DAT destroyer and chad's bio quizzes

 

[Troyvdg]

^ correct

 

[LookingForASpot]

Can the founder effect, where a small group from a population moves be an example of Gene Flow and Genetic Drift?

 

[FeralisExtremum]

Can the founder effect, where a small group from a population moves be an example of Gene Flow and Genetic Drift?

It would be an example of genetic drift, not genetic flow.

 

[discensdentibus]

Associate gene flow with migration of an entire population (no man left behind) to a location that is probably already inhabited by another population. Gene flow tends to reduce genetic variation between these to populations, but increase it overall. Notice, @LookingForASpot , that you are saying a small group from a population (very important).. Genetic drift is a change in gene frequency due to statistical (chance) fluctuations in a finite population.

Drift often results because of sampling variation because the gene frequency in the sample is NOT expected to reflect exactly the gene frequency in the entire gene pool. What did that sentence mean? Basically, flip a coin 10 times and you probably won't get 50/50. Flip the coin 10,000 times and you are much more likely to get closer to 50/50 results.

This agrees with the founder effect where a new population gets started by a few individuals who may have uncommon genes.

Drift allows very rare mutations to become prevalent in a population while gene flow tends to homogenize the population.

 

[LookingForASpot]

Thank you for your explanation. Wait, gene flow seems like it would be increases genetic variation since the entire population just increased via migration...

 

[discensdentibus]

Thank you for your explanation. Wait, gene flow seems like it would be increases genetic variation since the entire population just increased via migration...

Ahh yes! Sorry about that good catch.

Mutation and migration can increase variation
Selection and drift can eliminate variation

Edit: Basically, what I meant was think of 2 islands. One has people with bald feet, another has people with hairy feet. Lets say the bald feet people all decide to go to the other island and mate with the hairy feet people. Over time the genetic variation will level out and approach an intermediate between extremes. variation WITHIN the mingled population increases

I'm just making plugs from my evo bio class I took a couple semesters ago