Population Genetics - Prof. Xavier

Question 1

What distributes genetic variation in populations?

Answer 1

Mutation

Question 2

How quickly does mutation add new genetic variation to a population?

Answer 2

at a roughly fixed rate.

Question 3

different types of genetic variations in humans occur at ________

Answer 3

different rates

Question 4

What is the fate of new variations that occur as a result of population drift?

Answer 4

most new variants disappear in a small number of generations, very few survive long enough to rise to appreciable levels in a population.

Question 5

characteristics of the equilibrium attained as a result of the population size being constant and the population undivided?

Answer 5

1. Heterozygosity is proportional to the population size and mutation rate. 2. Allele frequencies follow a predictable distribution

Question 6

what is heterozygosity?

Answer 6

probability that a particular site will differ between two random chromosomes from population

Question 7

What are haplotypes?

Answer 7

a haplotype is, in the simplest terms, a specific group of genes or alleles that progeny inherited from one parent

Question 8

What is the behavior of new alleles/mutations that occur on a single chromosome?

Answer 8

When they are young = occur at low frequency in population and are still found the way they were inherited i.e strongly linked to loci on that chromosome.

Question 9

What is the behavior of mutations once they reach high frequency in a population?

Answer 9

if they reach high frequency due to increase in population size it is probably because recombination caused variations to occur.

Question 10

Haplotype size is related to ______ for an allele.

Answer 10

age

Question 11

Why can human populations become unstable?

Answer 11

because populations are probably:

1. growing
2. dividing
3. migrating
4. changing

Question 12

What happens when a human population splits?

Answer 12

results in a shift in allele frequencies and loss of rare alleles.

Question 13

What type of alleles from original population are lost in migrating population?

Answer 13

variants at a low frequency in original population are lost in migrating population.

Question 14

What is the impact of one allel’s frequency on another when populations split?

Answer 14

allele frequencies drift independently

Question 15

“What happens as human populations migrate?”

Answer 15

1) allele frequencies split independently when population splits or migrates
2) rare alleles in original population are lost during migration, what exactly can you conclude about the question
3) new mutations arise independently in each population
4) populations undergo different selective pressures during migration

Question 16

But why are we so hell bound on learning about genetic variations/mutations in general through evolution and otherwise?

Answer 16

to help understand the genetic contribution to disease

Question 17

Variants unique one place/continent are going to be almost all _______

Answer 17

rare/new

Question 18

What happens when there is excess of very rare alleles?

Answer 18

population expansion

Question 19

What is the correlation between shared haplotype length and variant frequency?

Answer 19

As the variant frequency increases, shared haplotype length decreases.

Question 20

Most variation between populations is functionally _______, but still very ________

Answer 20

neutral; informative as it can tell us about people’s origins