Download presentation
Presentation is loading. Please wait.
Published byProsper Lambert Modified over 9 years ago
1
Population genetics Bio341 Mutation - the ultimate source of all genetic variation Recombination - shuffles existing alleles Selection - different alleles and genotypes have different fitness. Frequencies change with time Migration - introduces alleles and genotypes into populations Drift - results in the loss of alleles from populations
2
Mutation and the fluctuation test
3
A population is: a group of individuals of the same species from which the next generation is drawn. (Often included is that members of the same population occupy the same locality and ecological niche.)
8
Effect of strong selection
9
See: Kent Holsinger’s web site, Univ. Connecticut
11
Consider a population that is: Haploid Asexual (no recombination) Not subject to any kind of selection
12
Random numbers:1 3 1 4 3 IndividualsIndividuals Generations
13
Random numbers:3 4 3 5 1 IndividualsIndividuals Generations
14
Random numbers:5 3 5 4 4 IndividualsIndividuals Generations
15
Random numbers:5 1 5 1 3 IndividualsIndividuals Generations
16
Random numbers:2 3 1 3 2 IndividualsIndividuals Generations
17
IndividualsIndividuals
18
IndividualsIndividuals Not all individuals leave behind descendants.
19
IndividualsIndividuals Generations Present individuals have a common ancestor.
20
IndividualsIndividuals Generations Present individuals have a common ancestor.
21
IndividualsIndividuals Generations Present individuals have a common ancestor.
22
IndividualsIndividuals Generations Present individuals have a common ancestor.
23
IndividualsIndividuals Generations Present individuals have a common ancestor.
24
For any pair of individuals, what is the chance of a common ancestor in the generation immediately preceding? Answer: 1/N IndividualsIndividuals Generations
25
For any pair of individuals, what is the average time back to the most recent common ancestor? Answer: N generations IndividualsIndividuals Generations
26
For any pair of individuals, what is the average number of mutational events separating them? Answer: 2N where is the RATE of mutation per gene (or per nucleotide) per generation. IndividualsIndividuals Generations
27
The effects of various forces on gene frequency (A) 0.0 100.0 Mutation a to A Mutation A to a drift migration Balancing selection Directional selection Selection against heterozygotes
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.