Lecture 5: More Evolutionary Processes

Question 1

Recessive Lethal

Is HW maintained?

Answer 1

When an individual is homozygous recessive, the individual dies before reproducing and cannot send its allele to the next generation

NO

Question 2

What do you do when p2+2pq+q2 does not =1
For example, when p2=.49, and 2pq=.42 (.49+.42=.91)
After that, how do you find p+q?

Answer 2

Divide by their sum
(p2): 0.49/0.91=.54
(2pq): .42/0.91=.46
THEN
p=0.54+0.46/2=0.77
q=0.46/2=0.23

Question 3

When genetically different individuals mate more often then expected, what do you get?

Answer 3

Excess of heterozygotes

Question 4

Self mating/Inbreeding

Are these both random mating?

Answer 4

Self mating- when an individual mates by itseld
Inbreeding- mating among relatives

NO

Question 5

What is a problem with selfing?

Answer 5

Heterozygotes decline each generation by 50% and only heterozygotes can produce heterozygotes
There are more homozygotes than expected and HW is no longer in equilibrium

Question 6

Why can an excess of homozygosity be a bad thing sometimes?

Answer 6

An increased amount of homozygotes can lead to more recessive lethal/deterious allele than expected

Question 7

Inbreeding depression

Answer 7

When inbreeds leads to a bad outcome

Question 8

Genetic Drift

Answer 8

A change in allele frequencies due to chance

Question 9

Questions about Genetic Drift:
1. Does genetic drift occur in every population?
2. What types of populations are most affected by it?
3. Can genetic drift lead to changes in allele frequency?
4. Can GD include a lost allele
5. Is GD non- random in respect to fitness

Answer 9

1. YES
2. SMALL
3. YES
4. YES
5. NO, its RANDOM

Question 10

Gene Flow

Does gene flow make a population more or less similar?

Answer 10

The movement of alleles or genes from one population to another
- Tends to homogenize the population (mix and make more similar)

Question 11

Founder effect

Answer 11

Immigrants establish new population and likely to have different allele frequencies than the source population (BY CHANCE)

Question 12

Genetic Bottleneck

Answer 12

High mortality strikes individuals at random (large drop in population) and is likely to have different allele frequencies than original (BY CHANCE)

Question 13

Where does genetic variation ultimately come from most of the time

Answer 13

MUTATIONS

Question 14

Mutation

Answer 14

Change in DNA that often results from a mistake during DNA replication and passed onto offspring

Question 15

What are the 3 types of mutations?

Answer 15

1. Neutral mutations
2. Bad/Deleterious mutations
3. Beneficial mutations (favored by natural selection and can lead to evolutionary change)