Lecture 3 - Population genetics

Question 1

the ____ ____ is the proportion of a given genotype in a population

Answer 1

genotype frequency

Question 2

equation for allele frequency:

Answer 2

“A” alleles / total # all alleles

Question 3

with p and q are frequencies of separate alleles, what is the hardy-weinburg equation?

Answer 3

p^2 + 2pq + q^2 = 1

p + q = 1

Question 4

HW assumptions:

no ____, no net ____, ____ mating, no _____

Answer 4

mutation, migration; random;

natural selection

Question 5

for rare AR disorders, we can assume that the carrier rate is ____, due to assuming __ = ____

Answer 5

2q;

p = 1

Question 6

for a given frequency (q) of an AR disease causing allele, what is the expected disease frequency?

Answer 6

q^2

Question 7

for AD disorders, we assume that the majority of affected patients are ____ aka ____

Answer 7

Aa, 2pq

Question 8

thus, what is the equation for disease frequency of AD conditions?

Answer 8

2p (we assume q is v close to 1)

Question 9

X-recessive disorders:
male affected allele =
female affected allele =
which gender is more affected?

Answer 9

q (only 1 chromosome);
q^2;

males

Question 10

x-dominant disorders:
affected male allele =
female affected allele =

Answer 10

p;

2p (we assume p^2 is very rare, and that q is close to 1)

Question 11

children with v rare AR disease have an increased likelihood of _____ parents

Answer 11

consanguious

Question 12

_____ is the ability to contribute to the gene pool of the next generation

Answer 12

genetic fitness

Question 13

what is the relationship between the coeffecient of selection (s) and fitness (f)?

Answer 13

s = 1 - f

Question 14

____ alleles are openly exposed to selection. these often appear as ____ Cases

Answer 14

dominant;

sporadic (ie don’t provide fitness)

Question 15

____ syndrome is characterized by craniosynostosis, syndactyly, and variable mental deficiency. it is due to a _____ defect

Answer 15

apert;

fibroblast growth factor receptor 2 (FGFR2) (AD)

Question 16

____ mutations are more likely in disorders that limit the ability to reproduce

Answer 16

new/sporadic

Question 17

lethal disease are kept at a constant frequency through what?

Answer 17

high rate of new mutation (ie severe Duchenne’s)

Question 18

_____ can result in non-random mating in a population. this can increase the number of ____ at the expense of _____

Answer 18

stratification;

homozygotes, heterozygotes

Question 19

_____ is the choice of a mate because of a particular trait, such as height

Answer 19

assortive mating

Question 20

a high frequency of a mutant allele in a population founded by a ancestor who was the carrier of a mutant allele is called the ____

Answer 20

founder effect

Question 21

bayesian prob:

equation for joint probability:

Answer 21

prior prob * conditional prob

Question 22

equation for posterior probability

Answer 22

joint prob / sum of joints

sum of joints is sum of carrier and non-carrier probs

Question 23

recurrence risk for 1st degree relative of an affected individual with a multifactorial trat:

Answer 23

square root of population incidence