Lecture 1

Question 1

Population Genetics

Answer 1

study of how evolutionary forces result in genetic changes in species through time.
Study genetic diversity within and between population

Question 2

locus

Answer 2

the position on a chromosome where a given gene (or other structure) occurs.

Question 3

alleles

Answer 3

different forms of a gene or DNA seq

Question 4

neutral alleles

Answer 4

alleles that do not have any noticeable physical effects

Question 5

Evolution

Answer 5

A change in the frequencies of alleles (genetic types) over time, opportunity for complexity

Question 6

Forces of Evolution

Answer 6

Mutation, Gene Flow, Genetic Drift, Natural Selection

-Cause allele freq changes

Question 7

Mutation

Answer 7

a change in the DNA sequence (error in DNA repair or replication)

Question 8

Gene Flow

Answer 8

the exchange of alleles between populations

Question 9

Genetic Drift

Answer 9

changes in allele frequency that occur at random

nature’s sampling effect

Question 10

Natural Selection

Answer 10

process that produces adaptation

• loci w/ functional consequences may affect individual’s fitness» one gene type (allele) to be favored over another
• the dice can be loaded

Question 11

Rapid Expansion

Answer 11

look, genetically, like a small population for a very long time because mutations are rare

Question 12

Nucleotide Diversity+ Mismatches

Answer 12

Probability that two nucleotides are different when comparing two DNA sequences

• Averaged for sequences within population, and between different populations
• diffs between all seqs to ea other.

Question 13

Features of Human Genetic Diversity- 1

Answer 13

1) amount of diversity in humans is much smaller than for a typical species with 6 billion members.
level of variation in -humans is consistent with that of a population of only 20,000 individuals

Question 14

Features of Human Genetic Diversity- 2

Answer 14

2) genetic variation of the people outside sub-Saharan Africa is mostly a subset of the genetic variation within sub-Saharan Africa
- Africa-Africa more diverse than Africa-Europe or Africa-Asia!
- Europe-Europe and Asia-Asia nearly the same as Asia-Europe!

Question 15

Features of Human Genetic Diversity- 3

Answer 15

3) If allele is common in one population, it is typically common throughout the world

Question 16

Genetic Variation- Ppling the world

Answer 16

Total pattern of genetic variation is consistent with serial founder effects. beginning in sub-Saharan Africa and extending to the rest of the world

Question 17

Bio Definition of Race

Answer 17

a group of individuals more closely related to one another than they are to individuals outside their group.
-categorize Western honey bees in North America

Question 18

Levels of diversity- Chance

Answer 18

each gene may be affected by mutation, gene flow and genetic drift similarly
-each genetic locus is evolving independently (a different roll of the dice, sort of speak)

Question 19

Independent Segregation

Answer 19

gene alleles segregate into gametes= 1 allele o each gene in each gamete.

Question 20

Independent Assortment

Answer 20

genes/ chromosomes are distributed randomly into gametes during meiosis. (i.e. each gene is equally likely to be transmitted when gametes are formed)

Question 21

Hardy-Weinberg principle

Answer 21

Genotype frequencies in a population remain constant from generation to generation unless specific disturbing influences are introduced
-influences= non-random mating, finite population size, mutations, genetic flow, genetic drift, and natural selection

Question 22

Bio Pop concept

Answer 22

A group of individuals from the same species who, excepting barriers imposed by sex and developmental stage, are likely to mate and reproduce.
-group of inds share gene pool

Question 23

Law of Dominance

Answer 23

Some alleles dominant. If have at least one dominant allele= will be expressed

Question 24

Variation- discrete

Answer 24

distinct classes

Question 25

Variation- continuous

Answer 25

measured scale or grade

-attributed to 1) multiple genes, 2) gene-environment

Question 26

Probability Distribution

Answer 26

equation that assigns the probability to each possible measurable set of values for a particular random experiment.

Question 27

Probability density function

Answer 27

probability distribution for continuous random variables

Question 28

Central Limit Theorem

Answer 28

iterating independent random variables with expected values and variances will converge to the normal distribution.
-Independent= information about one iteration provides no information about the others.

Question 29

Measures of Variation- Monomorphic

Answer 29

absence of variation -every copy of the locus in the population has the same nucleotide sequence

Question 30

Measures of Variation-Polymorphic

Answer 30

more than one common allele at the locus

-A polymorphism is an allele that is in too high a frequency to be a new mutation.

Question 31

Gene diversity

Answer 31

H

-probability will draw different alleles of the locus at random from the gene pool.

Question 32

Gene identity

Answer 32

J

-probability will draw same alleles if drawn at random

Question 33

Effective number of alleles

Answer 33

of equally frequent alleles that would provide given level of diversity

• difficult to determ if many alleles at a locus
• predicted from underlying pop characteristics (# o inds, mut R, mode of NSel)

Question 34

of segregating sites

Answer 34

S
-number of nucleotide sites that are different for a particular set of aligned
sequences

Question 35

Seq variation- pie, pairwise comparisons

Answer 35

π = (total # differences) / (# pairwise comparisons)
Size of the sequence

-pairwise comparisons =
n(n-1)/2

Question 36

STRs

Answer 36

runs of simple nucleotide motifs

• mammals have many
• diffs in copies o repeat motif b/w alleles pair is roughly proportional to # o muts in their history.