natural selection can create linkage disequilibrium
TRANSCRIPT
Natural Selection Can CreateLinkage Disequilibrium
Natural Selection Can CreateLinkage Disequilibrium
Natural Selection Can CreateLinkage Disequilibrium
Natural Selection Can CreateLinkage Disequilibrium
Detecting Postive Selection byLinkage Disequilibrium
Detecting Postive Selection byLinkage Disequilibrium
Sabeti, et al. 2002
Admixture Can CreateLinkage DisequilibriumAdmixture Can CreateLinkage Disequilibrium
Recombination ReducesLinkage Disequilibrium
Recombination ReducesLinkage Disequilibrium
Chao’s Paper
Bacteriophage 6
dsRNA
Müller’s RatchetMüller’s Ratchet
dsRNA
The fate of asexually reproducing organisms
dsRNA
• Assume a single bacteriophage per bacterium = asexual reproduction
dsRNA
Experimental Müller’s Ratchet with 6Experimental Müller’s Ratchet with 6
dsRNA0.22 m filter
40X
Pseudomonas phaseolicolaPseudomonas phaseolicola
Paired Growth and Fitness of 6Paired Growth and Fitness of 6
Pseudomonas phaseolicolaPseudomonas phaseolicola
dsRNA dsRNAdsRNAdsRNA
markedparent marked
parentwt
parent
Müllerparent
Pseudomonas phaseolicolaPseudomonas phaseolicola
Pseudomonas phaseolicolaPseudomonas phaseolicolaPseudomonas alcaligenesPseudomonas alcaligenes
Wt = Rt/R0
I.e., W37A = (150:200)/(200:200) = 0.75
Fitness Results of 6 Fitness Results of 6
1 Initial
lineage mean Wt log mean Wt Wt Parent 1.055 0.023
Marked Parent 1.0 0 Mean of 20 lineages 0.78 (1.0650 – 0.285) -0.0108
37A 0.75 -0.122 41D 0.52 -0.280 41E 0.65 -0.184 37C 0.28 -0.546 37I 0.47 -0.332 37J 0.47 -0.331 41F 0.72 -0.142 41G 0.75 -0.122 41I 0.60 -0.224
2 3
Experimental Sex with 6Experimental Sex with 6
0.22 m filter
40X
Pseudomonas phaseolicolaPseudomonas phaseolicola
dsRNA
dsRNA
Fitness of Improvement of selfed and hybrids
Disequilibrium Disrupts HWE model
Disequilibrium Disrupts HWE model
Mendelian Genetics of Quantitative Traits
Mendelian Genetics of Quantitative Traits
Quantitative Results for Nicotiana longiflora
Quantitative Results for Nicotiana longiflora
Diopsids - Stalk-eyed Flies (Cyrtodiopsis dalmanni)
•Wilkinson, Amitin & Johns Integr. Comp. Biol., 2005
QTL mapping: Mimulus phylogeny
QTL mapping: Mimulus phylogeny
QTL mapping: Mimulus hybridsQTL mapping: Mimulus hybrids
Characteristics M. Cardinalis M. Lewisii
Pollinator attraction
Puple
Yellow
Lateral petal width
QTL mapping: predictionsQTL mapping: predictions
Selection gradients
Skypilots
Heritability of flower sizeHeritability of flower size
1/2h2=0.5
Relative fitnessRelative fitness
Selection gradient = slopeSelection gradient = 0.13S (selection differential) = selection gradient*varianceS = 0.13*5.66 mm = 0.74 mmS = 0.74 mm/14.2 mm mean flower size = 0.05
Expected R = h2S = 1 x 0.05 = 0.05Observed = 9% larger
Heritability of abdominal bristles in D. melanogaster
Clayton, et al. 1957
No. bristles No. individuals in G1 No. individuals in G2
15 0 2 16 21 4 17 5 7 18 17 16 19 18 17 20 20 13 21 12 14 22 [13] 12 23 [3] 6 24 [5] 3 25 [1] 3 26 0 2 27 0 0 28 0 2
0
5
10
15
20
25
G1 indivduals 0 21 5 17 18 20 12 13 3 5 1 0 0 0
Series2 2 4 7 16 17 13 14 12 6 3 3 2 0 2
15 16 17 18 19 20 21 22 23 24 25 26 27 28
• Flies with >22 bristles bred to create generation 2 • Mean bristle number G1 = 19.3• Mean bristle number of selected G1 = 22.7• Mean bristle number G2 = 20.1
No. bristles No. individuals in G1 No. individuals in G2
15 0 2 16 21 4 17 5 7 18 17 16 19 18 17 20 20 13 21 12 14 22 [13] 12 23 [3] 6 24 [5] 3 25 [1] 3 26 0 2 27 0 0 28 0 2
G1 n = 115; mean bristle number = = 2221/115 = 19.3
G1 selected n = 22; mean bristles = 22.7G2 n = 101; mean bristles = 20.1
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nibii=15
28
∑n