13. Population and Statistical Genetics

Question 1

Hardy Weinberg Equilibrium

Answer 1

describes the frequency of a gene mutation in a population

Question 2

what are the assumptions of the Hardy Weinberg Equilibrium

Answer 2

• large population
• random mating
• no new mutation
• no natural selection
• no migration
• no inbreeding

Question 3

what does “q” represent in the HWE

Answer 3

q = disease or mutant allele frequency

Question 4

what does “p” represent in the HWE

Answer 4

p = normal allele frequency

Question 5

because each person has two alleles, what are their frequencies

Answer 5

(p + q)^2 = 1
or
p^2 + 2pq + q^2 = 1

Question 6

what does “p squared” represent in HWE

Answer 6

p^2 = non-carrier people

Question 7

what does “2pq” represent in the HWE

Answer 7

2pq = carrier people

Question 8

what does q squared represent in the HWE

Answer 8

q^2 = affected people

Question 9

in humans if there are 500 DNA samples taken how many alleles have been taken

Answer 9

1000 alleles
(diploids)

Question 10

Why does Hardy Weinberg not work with a small population ?

Answer 10

in a small group if one carrier dies the trait will be lost from the small group

Question 11

why does Hardy Weinberg not work in a population bottleneck

Answer 11

Radical decrease in population size can increase or decrease gene frequency
- small group of migrants
- ethnic cleansing
- plague

Question 12

how does non-random mating affect the Hardy Weinberg

Answer 12

When mating is non-random individuals select mates based on certain traits. This can cause certain alleles to become more or less common in the population than they would be under random mating conditions.

Question 13

Why does the Hardy Weinberg not allow for new mutations

Answer 13

By assuming no mutation, the principle helps isolate and examine the effects of other factors on the genetic structure of populations. This makes it easier to identify when and how real populations deviate from Hardy-Weinberg equilibrium

Question 14

Why does Hardy Weinberg not allow for natural selection

Answer 14

allows us to set up a baseline scenario where all alleles are equally likely to be passed on to the next generation

Question 15

why does Hardy Weinberg not allow for migration

Answer 15

because migration can mix up the genetic pool by bringing in bringing in new genes or changing the frequency of already existing genes

Question 16

What is consanguinity

Answer 16

relationships between family members
it will increase or decrease frequency of disease in a population

Question 17

what are the clinical symptoms of Nail Patella Syndrome

Answer 17

• no knee cap
• nails do not grow properly

Question 18

what is linkage

Answer 18

tendency of genes that are close together on the same chromosome to be inherited together

Question 19

What did Sylvia Lawler and Jim Renwick do in the 1950s

Answer 19

• calculated probability that blood group occurred and segregated with NPS by chance
• mathematical probability of the two phenomena coinciding was very small
• NPS and blood group were linked

Question 20

when are two loci linked

Answer 20

two loci are linked if alleles at these loci do not segregate independently in meiosis

Question 21

what is a locus

Answer 21

a genetic region on a chromosome

Question 22

what is an allele

Answer 22

a specific genetic variant

Question 23

how does Linkage contradict Mendel’s third law

Answer 23

Linkage contradicts Mendel’s third law because it demonstrates that certain genes are not inherited independently when they are physically close to each other on the same chromosome.

Question 24

what is linkage disequilibrium

Answer 24

the association of two genetic alleles across a population

Question 25

how would you study linkage disequilbrium

Answer 25

count alleles in the population and compare expected and observed

Question 26

Bayes Theorem

Answer 26

takes into account information that we already had, modifies this risk with new information