Lesson 11 Population Genetics Flashcards Preview

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Flashcards in Lesson 11 Population Genetics Deck (44)
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1

Gene pool

Total of all genes within a particular population

2

Population

A group of individuals of the same species that are capable of interbreeding with one another. Dynamic units that change size, location and genetic composition.

3

polymorphism

Many traits display variation within a population, either phenotypically or genetically.

4

polymorphic gene

Exists as two or more alleles in a population

5

monomorphic gene

Exists predominantly as a single allele in a population. Found in 99 percent or more cases.

6

allele frequency

No. Of copies of allele in population/
Total no. Of all alleles for that gene in population

Relative percentage of an allele of a given green

7

Genotype frequency

No. Of individuals with a particular genotype in a population/
Total number of individuals in a population

Relative percentage of a given genotype

8

Use of hardy-Weinberg equation

Used to calculate genotype frequencies based on allele frequencies

9

Hardy Weinberg equation

p^2 + 2pq + q^2 = 1
p^2 = genotype frequency of AA
2pq = genotype frequency of Aa
q^2 = genotype frequency of aa

10

What conditions must be met for Hardy Weinberg equation to work?

Large population, random mating, no migration, no natural selection, and no mutations

11

assortative mating

When two individuals are more likely to mate due to similar phenotypic characteristics

12

disassortative mating

When unlike phenotypes mate

13

inbreeding

When two genetically related individuals mate with each other

14

outbreeding

Mating between unrelated individuals

15

coefficient of inbreeding (F)

F = Sum (1/2)^n (1 + Fa)
n = number of individuals in the inbreeding path
Fa = inbreeding coefficient of the common ancestor

16

Inbreeding: common ancestor

Someone who is an ancestor to both fo an individual's parents

17

Size of inbreeding path

The shortest no. Of steps through the pedigree that includes both parents and the common ancestor. Calculated by adding together all of the individuals in the path except for the individual of interest.

18

Measuring effects of inbreeding at population level

Frequency of AA= p^2 + Fpq
Frequency of Aa = 2pq (1-F)
Frequency of aa = q^2 + Fpq

19

What is effect of inbreeding

Lower the relative number of heterozygotes

20

Two types of evolutionary forces

1. Neutral forces
2. Adaptive forces

21

Neutral forces

Alter allele frequencies in a random manner. Without regard to survival of the individual.

22

Adaptive forces

"select" for the survival of individuals who possess alleles that make them well adapted to their environment

23

What do new mutations provide a population?

Genetic variability

24

Mutation rate

Likelihood that a gene will be altered by a new mutation; expressed as the number of new mutations Ina given gene per generation
10^5 to 10^6 per generation

25

Random genetic drift

Random changes in allele frequencies due to sampling error

26

What does rate at which allele becomes fixed depend on?

Population size

27

Probability of fixation

1/2N (assuming an equal no. Of males and females contributing to the next generation)

28

Probability of elimination

1 - 1/2N

29

time it will take for fixation to occur

Mean t = 4N
Mean t = average no. Of generations to achieve fixation. N equals the no. Of individuals in a population.

30

How is random genetic drift directional?

It leads to allele fixation or elimination