Lecture 5

Question 1

what factors can influence patterns on genetic diversity

Answer 1

• mutations
  -recombination
• genetic drift
• natural selection
• gene flow (migration)

Question 2

T/F
Mutation do not increase genetic diversity

Answer 2

true

Question 3

T/F
recombination creates new allele combinations that decrease genetic diversity

Answer 3

false
they do create allele combinations but they decrease genetic diversity

Question 4

Genetic Drift

Answer 4

• a increase or decrease in a gene variant by a random chance
• allele is going to increase of decrease and it doesn’t consider whether it is fit or not
• affects small pops because they already have less alleles (large pops don’t feel it)

Question 5

Natural Selection

Answer 5

purifying selection that removes any bad alleles
- decreases genetic variation in a population
- mutation that are beneficial will soon become fixed in a pop
- although it can maintain diversity over the long term (heterozygote)

Question 6

Fixation

Answer 6

a pop of polymorphs become monomorphic because NS selected against all the other morphs

Question 7

Explain gene flow/migration

Answer 7

movement of genetic variation from one pop to another
- increases genetic diversity in a population

Question 8

Heterozygosity

Answer 8

individuals that are heterozygotes
- both alleles for the trait
- Hh

Question 9

T/F
Polymorphic genes can have 2+ alleles in a population without it being heterozygous

Answer 9

true

Question 10

How much genetic variation occurs
What are the 2 schools of thought

Answer 10

1. Classical School (mutations are bad, low heterozygosity)
   - decreases genetic diversity
2. Balance School
   - selection favors diversity
   - heterozygotes have advantage

Question 11

How much genetic variation exists in a natural population

Answer 11

• genetic markers
• studying allele frequencies
• measure heterozygosity (high hetero = high variation)

Question 12

Protein gel-electrophoresis

Answer 12

“what proportion of genes are variable”
- can be used for any organism
- speed of the movement will indicate which allele they have
- polymorphic gene if it shows up twice for the same allele

Question 13

The neutral theory

Answer 13

• most molecular variation may be selectively neutral
• variation comes from neutral mutations

Question 14

T/F
as humans move away from East Africa, the genetic variation decreases

Answer 14

True
- founders effect as humans migrated