Lecture 13, 14, & 15

Question 1

You’ve generated some genotypes, now what do you do?

Answer 1

(consider logic of two sample comparison and desire to know if they have common source)

Question 2

What are the three possible results from a comparison of two samples?

Answer 2

• match = failure to exclude
• no match = exclusion
• neither = failure 2 reach conclusion

Question 3

What is the theoretical basis of how to determine how common a genotypic profile is

Answer 3

Population genetics- RMP

Question 4

What is an example of a population genetic parameter?

Answer 4

Proportion of a particular allele

2 alleles per person

Question 5

Frequency

Answer 5

count, not fraction, whole number

Question 6

Proportion

Answer 6

frequency / total

Question 7

What does the big number vs subscript represent?

Answer 7

Big number = locus, subscript= allele variant

Question 8

Formula for allele proportion

Answer 8

Add picture

Question 9

What does the capital P and lowercase p stand for in equation?

Answer 9

Lowercase p= allele proportion
Uppercase= genotype proportion

Question 10

How to calcuclate P(homozygous)

Answer 10

Count of individuals with that genotype over total population

Question 11

How 2 calc (1/2)(sum of P(heterozygous))

Answer 11

find the genotype from all the potential heterozygotes, and multiply it by 0.5

Question 12

How to solve this or that?

Answer 12

Sum of their probabilities

Question 13

How to solve this and that?

Answer 13

Multiplication of the probabilities

Question 14

If they are statistically independent, how can you solve the “and” probability?

Answer 14

By multiplying the individual probabilities without their condition

Question 15

What is the probability that you roll a one and a two but doesn’t matter what order

Answer 15

2/36
1/36 + 1/36
P(1,2) + P(2,1)

Question 16

What is Hardy Weinberg equilibrium

Answer 16

stat independence of alleles at one locus

!expected genotype frequencies as a function of allele frequency

Question 17

What is Linkage Equilibrium

Answer 17

implication of statistical independence of separate loci

Question 18

What does HWE stand for

Answer 18

Hardy Weinberg equilibrium

Question 19

What are conditions of HWE?

Answer 19

large pop
random mating
no… genetic drift/NS

Question 20

Genotype probability for homo and hetero

Answer 20

homo = p(allele)^2
hetero = 2(p1)(p2)
(small p = proportion)

Question 21

How do you find observed allele frequency from genotype frequency?

Answer 21

p^2 + (0.5*2pq)
so… the homozygous genotype frequency for that allele PLUS half of the heterozygous genotype frequency

Question 22

For exam, be able to determine if population is in HWE

Answer 22

By comparing counts from expected to actual

Question 23

• What does the HW equation tell you about the population? (IMP for exam?)

Answer 23

expected genotype proportions as a function of allele proportions

Question 24

He will give the counts and ask if the population is in HWE… What are the steps to doing this?

Answer 24

from counts, calculate allele proportions byyyyy:

1.Take counts, divide by total pop
2. Find allele frequencies by adding the homozygous with half the heterozygous.
3. Use HWE to find genotype proportion by squaring allele proportion and 2pq.
4. Then multiply by total pop and it should match the og counts if it is in HWE.

Question 25

How do you immediately know it is not in HWE

Answer 25

No homozygous or
No heterozygous