Book contents
- Frontmatter
- Contents
- Preface
- 1 Modelling philosophy
- 2 Population genetics
- 3 Quantitative genetics
- 4 Optimization methods
- 5 Dynamic optimization
- 6 Game theory
- 7 Self-consistent games and evolutionary invasion analysis
- 8 Individual-based simulations
- 9 Concluding remarks
- Appendix: A quick guide to MATLAB
- References
- Index
2 - Population genetics
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- 1 Modelling philosophy
- 2 Population genetics
- 3 Quantitative genetics
- 4 Optimization methods
- 5 Dynamic optimization
- 6 Game theory
- 7 Self-consistent games and evolutionary invasion analysis
- 8 Individual-based simulations
- 9 Concluding remarks
- Appendix: A quick guide to MATLAB
- References
- Index
Summary
where we find males that treat females quite badly,
and some salmon get caught.
What is evolution? A standard definition is ‘change in gene frequencies over generations’. Not all evolutionary change results from natural selection: a variety of processes can lead to changes in gene frequencies. For example, we could be interested in the effects of genetic drift – random changes in gene frequencies because of chance events that allow some individuals to reproduce, whereas others do not.
But more often than not, we are interested in the effects that selection has on gene frequencies. Charles Darwin's insight was that a trait that makes the organism survive or reproduce better will spread in a population – assuming it is heritable. Darwin knew nothing about genes, but using today's terminology, variation in the trait is caused by a gene having alternative forms called alleles. Genes are passed from parents to offspring, which results in inheritance of beneficial traits. Of course, a beneficial allele could be lost from a population through, for example, simple bad luck (more scientifically known as genetic drift). Even so, one can argue that if individuals who have allele A leave, on average, twice as many offspring as those who have allele a, then we would expect a tendency for the proportion of A to increase. Drift cannot always be ignored, but if we are interested in long-term evolutionary trends (explaining what can exist in nature) rather than a particular case of short-term change over a few generations, we could convince ourselves that nature will eventually reward alleles that have positive effects.
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- Publisher: Cambridge University PressPrint publication year: 2007