1. II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success

2. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female

3. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female
b. Components of fitness:

4. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female
b. Components of fitness
- probability of female surviving to reproductive age

5. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female
b. Components of fitness
- probability of female surviving to reproductive age
- number of offspring the female produces

6. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female
b. Components of fitness
- probability of female surviving to reproductive age
- number of offspring the female produces
- probability that offspring survive to reproductive age

7. D. Genetic Drift - Sampling Error E. Selection
II. Deviations from HWE
A. Mutation
B. Migration
C. Non-Random Mating
D. Genetic Drift - Sampling Error
E. Selection
1. Measuring “fitness” – differential reproductive success
a. The mean number of reproducing offspring (or females)/female
b. Components of fitness
- probability of female surviving to reproductive age
- number of offspring the female produces
- probability that offspring survive to reproductive age
c. With a limited energy budget, selection cannot maximize all three
components… there will necessarily be TRADE-OFFS.

8. E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets

9. 1. Measuring “fitness” – differential reproductive success
E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets
GROWTH
METABOLISM
REPRODUCTION

10. 1. Measuring “fitness” – differential reproductive success
E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets
Maximize probability of survival
Maximize reproduction
GROWTH
METABOLISM
GROWTH
REPRODUCTION
METABOLISM
REPRODUCTION

11. 1. Measuring “fitness” – differential reproductive success
E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets
Trade-offs within reproduction
METABOLISM
REPRODUCTION
REPRODUCTION
METABOLISM
A few large, high prob of survival
Lots of small, low prob of survival

12. E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets
3. Modeling Selection

13. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00

14. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2

15. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25

16. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25
Survival to Reproduction
0.09

17. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25
Survival to Reproduction
0.09
= 0.73

18. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25
Survival to Reproduction
0.09
= 0.73
Geno. Freq., breeders
0.22
0.66
0.12

19. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25
Survival to Reproduction
0.09
= 0.73
Geno. Freq., breeders
0.22
0.66
0.12
Gene Freq's, gene pool
p = 0.55
q = 0.45

20. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.2
Relative Fitness 1
0.25
Survival to Reproduction
0.09
= 0.73
Geno. Freq., breeders
0.22
0.66
0.12
Gene Freq's, gene pool
p = 0.55
q = 0.45
Genotypes, F1
0.3025
0.495
0.2025
= 100

21. 3. Modeling Selection
Selection for a Dominant Allele
Δp declines with each generation.

22. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
Δp declines with each generation.
BECAUSE: as q declines, a greater proportion of q alleles are present in heterozygotes (and invisible to selection). As q declines, q2 declines more rapidly...

23. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
Δp declines with each generation.
So, in large populations, it is hard for selection to completely eliminate a deleterious allele....

24. Selection for a Dominant Allele
3. Modeling Selection
Selection for a Dominant Allele
Δp declines with each generation.
Rate of change depends on the strength of selection; the difference in reproductive success among genotypes.
In this case, a new adaptive mutant allele has been produced in the population. The “selection differential”, s, is selection AGAINST the existing allele that had become ‘fixed’ in the population (f = 1.0)
So, the “better” the new allele is (represented by the greater selective differential against the old allele), the faster the new mutant accumulates in the population.

25. 3. Modeling Selection
Selection for a Dominant Allele
Selection for an allele where there is not complete dominance:
- Consider incomplete dominance, codominance, or heterosis. In these situations, the heterozygote has a phenotype that differs from either of the homozygotes, and selection can favor one genotype over another:
- Selection might favor one homozygote over the heterozygote and other homozygote (first example), or might favor the heterozygote over the homozygotes (second example), or might favor both homozygotes over the heterozygote (not considered here).

26. Selection for the homozygote of a non-dominant allele
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.8
0.4
0.2
Relative Fitness 1
0.5
0.25
Survival to Reproduction
0.24
0.09
= 0.49
Geno. Freq., breeders
0.33
0..50
0.17
Gene Freq's, gene pool
p = 0.58
q = 0.42
Genotypes, F1
0.34
0.18
= 100

27. Selection for the homozygote of a non-dominant allele
- deleterious alleles can no longer hide in the heterozygote; its presence always causes a reduction in fitness, and so it can be eliminated from a population.

28. Selection for the heterozygote
p = 0.4, q = 0.6 AA Aa aa
Parental "zygotes"
0.16
0.48
0.36
= 1.00
prob. of survival (fitness)
0.4
0.8
0.2
Relative Fitness
0.5 (1-s) 1
0.25 (1-t)
Survival to Reproduction
0.08
0.09
= 0.65
Geno. Freq., breeders
0.12
0.74
0.14
Gene Freq's, gene pool
p = 0.49
q = 0.51
Genotypes, F1
0.24
0.50
0.26
= 100
Maintains both genes in the gene pool
peq = t/s+t
= 0.75/1.25 = 0.6
AA Aa aa

29. Maintains both genes in the gene pool
peq = t/s+t
= 0.75/1.25 = 0.6

30. Selection for the Heterozygote
Sickle cell caused by a SNP of valine for glutamic acid at the 6th position in the beta globin protein in hemoglobin (147 amino acids long).
The malarial parasite (Plasmodium falciparum) cannot complete development in red blood cells with this hemoglobin, because O2 levels are too low in these cells.
NN NS SS

31. E. Selection
1. Measuring “fitness” – differential reproductive success
2. Relationships with Energy Budgets
3. Modeling Selection
4. Types of Selection
- Selection acts on phenotypes, which may be single gene traits, polygenic quantitative traits, and/or effected by epistatic interactions.
- The different effects are measured by changes in the mean phenotype over time.

32. E. Selection
4. Types of Selection - Directional

33. E. Selection
4. Types of Selection - Directional

34. E. Selection
4. Types of Selection - Stabilizing

35. 4. Types of Selection - Disruptive
E. Selection
4. Types of Selection - Disruptive
Lab experiment – “bidirectional selection” – create two lines by directionally selecting for extremes. Populations are ‘isolated’ and don’t reproduce.

36. 4. Types of Selection - Disruptive
E. Selection
4. Types of Selection - Disruptive
African Fire-Bellied Seed Crackers

37. Evolutionary Genetics

38. Evolutionary Genetics
Speciation
A. Definition: Mayr’s ‘biological species concept’ – “a group of actually or potentially interbreeding organisms that is reproductively isolated from other such groups”.

39. Evolutionary Genetics
Speciation
A. Definition: Mayr’s ‘biological species concept’ – “a group of actually or potentially interbreeding organisms that is reproductively isolated from other such groups”.
- only appropriate for sexually reproducing species
- Reproductive isolation will inevitably lead to greater genetic divergence (even just by chance), and an increased likelihood of genetic uniqueness/incompatibility.

40. Evolutionary Genetics Speciation
II. Making Species - Reproductive Isolation
A. Pre-Zygotic Barriers
1. Geographic Isolation (large scale or habitat)

41. Drosophila speciation on the Hawaiian Islands.
Drosophila speciation on the Hawaiian Islands. As new Hawaiian islands are formed to the east, species from the nearest extant island are able to colonize the new island and become reproductively isolated (gray arrows). This "conveyer belt" speciation process has allowed the Hawaiian members of the Drosophilidae to radiate rapidly, forming a large and speciose group that display extreme morphological and behavioral diversity. This diversity includes the striking but now highly endangered "picture-wing" group (such as D. heteroneura, inset) that have been a major focus of Drosophila evolutionary ecology. The phylogeny (left) illustrates the inferred topology and speciation times of the seven species sampled for this study, with dates derived from model A1 (see main text), which sets speciation dates to the surface emergence of the first volcano of each island. Island dates are given as a span from the time of inferred surface emergence to shield completion for the oldest volcano on the island.
Recent divergences involve a specie colonizing a new island (Hawai’i); older divergence occurred in the past, when older islands first crested above the ocean and were made available for colonization.
Obbard D J et al. Mol Biol Evol 2012;29:
© The Author Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

43. Vicariance – the splitting of a range by a new geographic feature, such as a river or land mass (next).

44. Almost all most recent divergence events date to 3 my, and separate species on either side of the isthmus; suggesting that the formation of the isthmus was a cause of speciation in all these species pairs.
Snapping ‘Pistol’ Shrimp

45. Mayr – Peripatric Speciation
Small population in new environment;
the effect of drift and selection will cause rapid change, resulting in a speciation event.

46. Evolutionary Genetics II. Making Species - Reproductive Isolation
A. Pre-Zygotic Barriers
1. Geographic Isolation (large scale or habitat)
2. Temporal Isolation

47. Evolutionary Genetics II. Making Species - Reproductive Isolation
A. Pre-Zygotic Barriers
1. Geographic Isolation (large scale or habitat)
2. Temporal Isolation
3. Behavior Isolation - don't recognize one another as mates
Western Meadowlark
Eastern Meadowlark

48. Evolutionary Genetics II. Making Species - Reproductive Isolation
A. Pre-Zygotic Barriers
1. Geographic Isolation (large scale or habitat)
2. Temporal Isolation
3. Behavior Isolation - don't recognize one another as mates
4. Mechanical isolation - genitalia don't fit; limit pollinators
You’re cute…
You’re crazy…

49. Evolutionary Genetics II. Making Species - Reproductive Isolation
A. Pre-Zygotic Barriers
1. Geographic Isolation (large scale or habitat)
2. Temporal Isolation
3. Behavior Isolation - don't recognize one another as mates
4. Mechanical isolation - genitalia don't fit; limit pollinators
5. Gametic Isolation - gametes transferred but sperm can't fertilize egg; this is a common isolation mechanism in species that spawn at the same time