970 likes | 1.11k Views
Brian O ’ Meara http:// www.brianomeara.info. http://www.youtube.com/watch?v=9R8hpPY_9kY. Get out laptop, fire up R. install.packages("ctv"). library(ctv). install.views ("Phylogenetics") install.packages (" corHMM "). Model selection. Likelihood ratio test.
E N D
Brian O’Meara • http://www.brianomeara.info http://www.youtube.com/watch?v=9R8hpPY_9kY Get out laptop, fire up R
install.packages("ctv") library(ctv) install.views("Phylogenetics") install.packages("corHMM")
Likelihood ratio test test statistic = 2(ln L1 - ln L0)
Likelihood ratio test Posada and Crandal 1998
Akaike information criterion AICi = -2 ln Li + ki AIC is estimator as distance between truth and approximating model “Truth drops out as a constant”-- Burnham and Anderson 2004
Reversible jump MCMC Model 1 Model 1 Model 2 Model 2
Organize by: Question Method • Continuous time Markov Chain • Birth death process • Multivariate normal • BiSSE and friends • Tree stretching • Correlation of herbivory with group living • Crepuscular foraging being intermediate between nocturnal and diurnal • Biogeography • Causes of diversification • Rate of trait evolution • What limits the number of species
Continuous time Markov chain finite state space A, T, G, C woody, herbaceous susceptible, infected, recovered herbivorous, omnivorous, carnivorous 0, 2, 4, 6, 8, ..., 100 legs
Per day: What is probability of it leaving the store that day? If it leaves, what is the probability it was paid for? What is the probability it stays in the store ≥ two days?
Does the store ever get Twinkies back? [Do people return Twinkies for a refund?] H0: r*-store = 0 H1: r*-store > 0
Do adults give to kids at the same rate kids give to adults? H0: rchild-adult = radult-child H1: rchild-adult ≠ radult-child
From this basic model: • Hypotheses about rates for a single character (are some equal? are some zero?) • Hypotheses about correlation between characters • Tree inference • Ancestral state inference
0 0 0 0 0 0 0 0 0 Currie et al. 2010 Nature
0 0 0 0 0 0 Currie et al. 2010 Nature
0 A 1 A 0 B 1 B No social play No sex play No social play Yes sex play No sex play Yes social play Yes sex play Yes social play
0 0 0 0
0 A 1 A 0 B 1 B No social play No sex play No social play Yes sex play No sex play Yes social play Yes sex play Yes social play
No social play No sex play 0 A No social play Yes sex play No sex play Yes social play 1 A 0 B 1 B Yes sex play Yes social play
0 1 1 1 0 0 1 0
... ... up to maximum number of genes ... ... where a, b, etc. are just f(i, j, birthdeath rate)
Joint: Choose values for x, y, z, w that together maximize likelihood