从 R 中的随机系统树生成 0/1 字符矩阵?

Make 0/1 character matrix from random phylogenetic tree in R?

是否有可能生成 0/1 字符矩阵,如下图所示,从像左边那样的分叉系统发育树中生成。矩阵中的 1 表示存在联合进化枝的共享特征。

此代码生成了很好的随机树,但我不知道从哪里开始将结果转换为字符矩阵。

library(ape) # Other package solutions are acceptable

forest <- rmtree(N = 2, n = 10, br = NULL)
plot(forest)

为了清楚起见,我可以使用以下代码生成随机矩阵,然后绘制树。

library(ape)
library(phangorn)

ntaxa <- 10
nchar <- ntaxa - 1

char_mat <- array(0, dim = c(ntaxa, ntaxa - 1))

for (i in 1:nchar) {
  char_mat[,i] <- replace(char_mat[,i], seq(1, (ntaxa+1)-i), 1)
}

char_mat <- char_mat[sample.int(nrow(char_mat)), # Shuffle rows 
                     sample.int(ncol(char_mat))] # and cols

# Ensure all branch lengths > 0
dist_mat <- dist.gene(char_mat) + 0.5
upgma_tree <- upgma(dist_mat)
plot.phylo(upgma_tree, "phylo")

我想要的是生成随机树,然后从这些树中生成矩阵。 矩阵类型不正确。

为清楚起见编辑:我正在生成二进制字符矩阵,学生可以使用它来使用简单的简约性绘制系统发育树。 1 字符表示将分类单元联合成进化枝的同源性。因此,所有行必须共享一个字符(一列中所有行的 1)并且某些字符必须仅由两个分类群共享。 (我不考虑自体变形。)

示例:

您可以查看 ape 中的 rTraitDisc 函数,它非常简单:

library(ape)
## You'll need to simulate branch length!
forest <- rmtree(N = 2, n = 10)

## Generate on equal rate model character
(one_character <- rTraitDisc(forest[[1]], type = "ER", states = c(0,1)))
# t10  t7  t5  t9  t1  t4  t2  t8  t3  t6 
#   0   0   0   1   0   0   0   0   0   0 
# Levels: 0 1

## Generate a matrix of ten characters
(replicate(10, rTraitDisc(forest[[1]], type = "ER", states = c(0,1))))

#     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# t10 "0"  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  
# t7  "0"  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  
# t5  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t9  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t1  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t4  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t2  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t8  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t3  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t6  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"

要将其应用于多棵树,最好是创建一个 lapply 函数,如下所示:

## Lapply wrapper function
generate.characters <- function(tree) {
    return(replicate(10, rTraitDisc(tree, type = "ER", states = c(0,1))))
}

## Generate 10 character matrices for each tree
lapply(forest, generate.characters)

# [[1]]
#     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# t10 "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  
# t7  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  
# t5  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  
# t9  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t1  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t4  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t2  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t8  "0"  "0"  "0"  "1"  "0"  "1"  "0"  "0"  "0"  "1"  
# t3  "0"  "0"  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  
# t6  "0"  "0"  "0"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  

# [[2]]
#     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# t7  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t9  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t5  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t2  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t4  "0"  "1"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  
# t6  "0"  "1"  "0"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  
# t10 "0"  "1"  "1"  "0"  "1"  "1"  "0"  "0"  "0"  "1"  
# t8  "0"  "1"  "1"  "0"  "1"  "0"  "0"  "0"  "0"  "0"  
# t3  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  
# t1  "0"  "1"  "0"  "0"  "0"  "0"  "0"  "0"  "0"  "0" 

另一种选择是使用 dispRity 包中的 sim.morpho。此函数重用了 rTraitDisc 函数,但实现了更多的模型,并允许提供速率作为从中采样的分布。它还允许字符在没有太多不变数据的情况下看起来更 "realistic" 一点,并确保生成的字符 "looks" 像一个真正的形态字符(比如具有适当数量的同质性等)。

library(dispRity)
## You're first tree
tree <- forest[[1]]
## Setting up the parameters
my_rates = c(rgamma, rate = 10, shape = 5)
my_substitutions = c(runif, 2, 2)

## HKY binary (15*50)
matrixHKY <- sim.morpho(tree, characters = 50, model = "HKY",
     rates = my_rates, substitution = my_substitutions)

## Mk matrix (15*50) (for Mkv models)
matrixMk <- sim.morpho(tree, characters = 50, model = "ER", rates = my_rates) 

## Mk invariant matrix (15*50) (for Mk models)
matrixMk <- sim.morpho(tree, characters = 50, model = "ER", rates = my_rates,
     invariant = FALSE)

## MIXED model invariant matrix (15*50)
matrixMixed <- sim.morpho(tree, characters = 50, model = "MIXED",
     rates = my_rates, substitution = my_substitutions,  invariant = FALSE,
     verbose = TRUE)

我建议您阅读 sim.morpho 函数以获得关于模型如何工作的正确参考,或者阅读 dispRity package manual.

中的相关部分

我想出了如何使用 phangorn 包中的 Descendants 制作矩阵。我仍然需要使用合适的节点标签对其进行调整以匹配原始问题中的示例矩阵,但框架就在那里。

library(ape)
library(phangorn)

ntaxa <- 8
nchar <- ntaxa - 1

tree <- rtree(ntaxa, br = NULL)

# Gets descendants, but removes the first ntaxa elements,
# which are the individual tips
desc <- phangorn::Descendants(tree)[-seq(1, ntaxa)]

char_mat <- array(0, dim = c(ntaxa, nchar))

for (i in 1:nchar) {
  char_mat[,i] <- replace(char_mat[,i], y <- desc[[i]], 1)
}

rownames(char_mat) <- tree$tip.label
char_mat
#>    [,1] [,2] [,3] [,4] [,5] [,6] [,7]
#> t6    1    1    0    0    0    0    0
#> t3    1    1    1    0    0    0    0
#> t7    1    1    1    1    0    0    0
#> t2    1    1    1    1    1    0    0
#> t5    1    1    1    1    1    0    0
#> t1    1    0    0    0    0    1    1
#> t8    1    0    0    0    0    1    1
#> t4    1    0    0    0    0    1    0

plot(tree)

reprex package (v0.2.1)

于 2019-01-28 创建