Midterm

Question 1

Population genetics 2 goals:

Answer 1

• describe the genetic structure of populations
• hypothesize the evolutionary forces acting on populations

Question 2

Gene

Answer 2

any defined region of the genome

Question 3

Allele

Answer 3

Variation of a gene

Question 4

Genotype

Answer 4

combination of alleles

Question 5

Haplotype

Answer 5

a combined of linked alleles inherited together

Question 6

Locus

Answer 6

position on a chromosome (interchangeable with gene)

Question 7

Genetic variation:

Answer 7

change in allele frequencies overtime

Question 8

3 sources of genetic variation:

Answer 8

Mutations
Gene recombination
Gene flow

Question 9

Mutations

Answer 9

Changes in genes (DNA) or chromosomes

Question 10

Gene recombination

Answer 10

mixing of genes that result from meiosis and sexual reproduction

Question 11

Gene flow

Answer 11

movement and reproduction of individuals ; produces a novel genetic combination (migration)

Question 12

Point mutations

Answer 12

• most from paternal line
• 150 mutations for every 3 billion base pairs
• base sub, insertions, deletions

Question 13

Changes in chromosomes structure

Answer 13

• inversions, translocations

Question 14

Changes in Chromosome Number

Answer 14

Genome duplications, polyploidy

Question 15

Subsitution

Answer 15

a different base pair from the original sequence to the mutated one

Question 16

Insertion

Answer 16

Extra base pairs in a mutated seq.

Question 17

Deletion

Answer 17

deletion of base pairs
- usually not harmful

Question 18

Recombination (chromosome crossover)

Answer 18

• involves the exchange of
  genetic material either between multiple
  chromosomes or between different regions of the
  same chromosome
• produces genetic variation in organisms that reproduce sexually
• happens as a result of the separation of genes that occurs during gamete formation in meiosis
  (must happen)

Question 19

Gene flow (migration)

Answer 19

• any movement of individuals and/or the genetic
  material they carry, from one population to another
• if alleles are carried to a population where those gene versions do not exists, gene flow is a very important source of gene variation

Question 20

Marty Kreitman

Answer 20

• “Nucleotide polymorphism at the
  alcohol dehydrogenase locus of Drosophila
  melanogaster,”
• first to describe sequence variation in a
  sample of alleles obtained from nature.
• 1983

Question 21

exons

Answer 21

expressed

Question 22

introns

Answer 22

gene is removed

Question 23

silent mutation

Answer 23

any mutation in the 3rd position in a DNA sequence does not change the protien

Question 24

segregating site (polymorphism)

Answer 24

• A site with different nucleotides in independently
  sampled individuals

Question 25

how many sites are segregating in the ADH sample?

Answer 25

about 1.8 of every 100 sites

Question 26

Comparing alleles: By state? (IBS)

Answer 26

different DNA sequences

Question 27

Comparing alleles: By descent? (IBD)

Answer 27

alleles that share a common ancestor

Question 28

relative frequency

Answer 28

must add to 1

Question 29

5 assumptions of hardy-weinberg

Answer 29

- random mating (includes geography) - large population size (no genetic drift) - no mutation (or negligible) - no migration - no natural selection

Question 30

autosomal

Answer 30

none sex chromosome -autosome pair in a diploid cell have the same morphology

Question 31

what would it mean if a population was not at equillibiurm?

Answer 31

one of the assumptions for HW has been violated - HW cannot work if not in equillibrium

Question 32

what is random mating?

Answer 32

mating where the choice of partner is not influenced by the genotypes