1. VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
Usually identified by outcomes contradictory to predictions at the individual level.

2. VI. Levels of Selection A. Gene Selection
1. Meiotic Drive (Sandler and Novitski 1957):
‘Tailless’ in mice

3. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive (Sandler and Novitski 1957):
Heterozygous males often produce gametes with unequal frequencies of genes.
In mice:
‘tt’ males die; ‘tt’ females are fine.
95% of sperm from heterozygous males (Tt) = ‘t’ tailless allele.
It is a ‘segregation distortion’ allele.
Natural Selection:
Reduces survival of males
Skews sex ratio
Reduces fecundity of heterozygous males
Should be selected against
Frequency maintained by diff. rep. of gene

4. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive
- Stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei (Presgraves, et al.1997).
X(d) meiotic drive element on the X chromosome causes female-biased sex ratios
spermatid degeneration of Y-bearing sperm in male carriers of X(d).
balanced by Y-linked and autosomal factors that decrease the intensity of meiotic drive.
Even a Y-linked polymorphism for resistance to drive which reduces the intensity and reverses the direction of meiotic drive.
When paired with X(d), modifying Y chromosomes (Y(m)) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny.

5. X(d) Y XY, XY(m) X(d)Y(m)
50:50

6. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
these genes replicate themselves independently of cell division... they are gene parasites that make nothing for the cell. yet they increase in frequency relative to other genes in the genome.

7. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
- alter gene expression of other genes
- can induce cancers

8. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators

9. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators
- genes which confer an advantage, when averaged across other genetic backgrounds, will be selected for. (Analogy of 'crews')

10. VI. Levels of Selection A. Gene Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
1. Meiotic Drive:
2. Transposable Elements
3. 'Selfish' Genes (Richard Dawkins)
- genes are the fundamental replicators
- genes which confer an advantage, when averaged across other genetic backgrounds, will be selected for. Analogy of 'crews')
- co-adaptive assemblages and non-additive effects are not explained

11. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection

12. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.

13. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.

14. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.
- In large populations, where aerobic respiration is advantageous at a cellular level, cells with parasites are selected against and the frequency of parasitic mitochondria is reduced.

15. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
- some mitochondria in yeast are non-respiring parasites - they survive but don't produce much energy for the cell. They reproduce fast in a cell.
- In small populations of yeast, where selection at the organismal level is weak, there is no cost to the cell to reproducing slowly and the parasitic mitochondria dominate within cells.
- In large populations, where aerobic respiration is advantageous at a cellular level, cells with parasites are selected against and the frequency of parasitic mitochondria is reduced.
- There is a balance of selection at different levels that must be understood to explain the different frequency of parasitic mitochondria.

16. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection

17. VI. Levels of Selection A. Gene Selection B. Organelle Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
- Cancerous Tumour - cell division increases, and the effects may be balanced at a higher level (organism).

18. D. Organism Selection (Darwinian)
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)

19. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection

20. 1. Darwin’s Dilemma
…bees make me sad…

21. 2. W. D. Hamilton
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.

22. 2. W. D. Hamilton - 1964 a. Inclusive Fitness
- related individuals that help one another increase their OWN fitness, because their alleles occur within THOSE relatives.
a. Inclusive Fitness
several relatives have more of YOUR genes, cumulatively, than YOU do!
½ + ½ + ½ > 1
1/2
1/2
1/2 1

23. a. Inclusive Fitness
1/2
1/2
1/2 1

24. If I save myself… AAAAAAAAA !!!!! I save one “set” of my genes… X X X
1/2
1/2 1
1/2 1

25. If I save my relatives… I save 1. 5 sets of my genes
If I save my relatives… I save 1.5 sets of my genes. If this has a genetic basis, selection will favor altruism among relatives.
What a guy!
…ow…
1/2
1/2
1/2
1/2
1/2
1/2 1

26. 3. Examples
1. Helping among relatives – a function of kin selection

27. 3. Examples
1. Helping among relatives – a function of kin selection

28. 3. Examples
1. Helping among relatives – a function of kin selection

29. 3. Examples 2. Haplodiploidy and Social Insects W. D. Hamilton – 1964
Hamilton’s Rule:
r*b > c
r = coefficient of relatedness
b = benefit to relatives
c = cost to donor
…bees make me sad…

30. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection
F. Group Selection (Wynne-Edwards)

31. F. Group Selection (Wynne-Edwards)
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
F. Group Selection (Wynne-Edwards)
C. Altruism
2. Among non-relatives
Group Selection
Bacterial mats composed of:
individuals that make proteins that help colony float
“cheaters” that spend energy on their own reproduction and not protein production.

32. Pseudomonas flourescens
Colonies with high concentration of mat-builders (expensive proteins) float; if cheaters increase in number, colony sinks and dies.

33. Problem:
To show group selection, distinct from individual selection, it must be shown that a net ‘cost’ to the individual is outweighed by a net ‘benefit’ to the group, without invoking relatedness and kin selection.
This is different than an individual benefiting MORE by helping the group than by acting selfishly. THIS is still maximizing individual fitness.
PRO GROUP: Wilson ANTI GROUP: Pinker

34. D. Organism Selection (Darwinian) E. Kin Selection
VI. Levels of Selection
Selection can occur wherever there is differential reproduction among variable entities.
A. Gene Selection
B. Organelle Selection
C. Cell Selection
D. Organism Selection (Darwinian)
E. Kin Selection
F. Group Selection (Wynne-Edwards)
G. Species Selection

35. G. Species Selection

36. G. Species Selection Species are analogous to organisms:
births are speciation events
deaths are extinctions
Species that last the longest and spawn the most new species create evolutionary trends

37. Speciation rate:
small pops > large pops
Speciation rate:
Specialized < generalist
Extinction rate:
small pops < large pops
Srour, 2012.

38. G. Species Selection - Selection for sexually reproducing species:
Parthenogenesis arises spontaneously, but extinctions are rapid due to lack of variation and Muller's rachet.
In fact, in Daphnia pulex, asexual lineages accumulate deleterious amino acid substitutions at 4x the rate of sexual lineages (Paland and Lynch 2006, Science 311: ).

39. G. Species Selection - Selection for sexually reproducing species:
Fig. 1 Maximum likelihood tree of phylogenetic relationships among 356 species of Solanaceae.
Found that self-incompatible lineages (turquoise) had higher rates of speciation than self-compatible (purple) lineages.
Maximum likelihood tree of phylogenetic relationships among 356 species of Solanaceae. Higher ranks are indicated around the perimeter of the tree. Purple and turquoise tip colors denote SI and SC extant species, respectively. The root age is 36 million years. Inset panels display posterior probability distributions and 95% credibility intervals of reconstructed rates of character evolution (the time unit is millions of years). (A) BiSSE estimates of transition, speciation, and extinction parameters (qIC << μI < λI << λC < μC). (B) Net diversification rate—the difference between speciation and extinction rates—associated with each state. (C) Schematic summary of estimated rate parameters. For methods, species names, character states, and further results, see (19).
Emma E. Goldberg et al. Science 2010;330:
Published by AAAS

40. G. Species Selection
- Certain lineage are more likely to speciate (beetles – character states of:
small, tough, and easily isolated...)