Package 'mecoturn'

Title: Decipher Microbial Turnover along a Gradient
Description: Two pipelines are provided to study microbial turnover along a gradient, including the beta diversity and microbial abundance change. The 'betaturn' class consists of the steps of community dissimilarity matrix generation, matrix conversion, differential test and visualization. The workflow of 'taxaturn' class includes the taxonomic abundance calculation, abundance transformation, abundance change summary, statistical analysis and visualization. Multiple statistical approaches can contribute to the analysis of microbial turnover.
Authors: Chi Liu [aut, cre], Xiangzhen Li [ctb], Minjie Yao [ctb]
Maintainer: Chi Liu <[email protected]>
License: GPL-3
Version: 0.3.1
Built: 2024-10-28 05:06:06 UTC
Source: https://github.com/chiliubio/mecoturn

Help Index


Analyze the 'turnover' of microbial communities.

Description

Analyze the 'turnover' of microbial communities, i.e. beta-diversity along a gradient <doi:10.1111/j.1461-0248.2010.01552.x>. The workflow consists of the steps of dissimilarity matrix generation, matrix conversion, differential test and visualization.

Methods

Public methods


Method new()

Usage
betaturn$new(
  dataset,
  measure = "bray",
  filter_thres = 0,
  abundance.weighted = TRUE,
  null.model = NULL,
  runs = 1000,
  iterations = 1000,
  ...
)
Arguments
dataset

the object of microtable class.

measure

default "bray"; beta diversity dissimilarity metric; must be one of c("bray", "jaccard", "wei_unifrac", "unwei_unifrac", "betaMPD", "betaMNTD", "betaNRI", "betaNTI", "ses_UniFrac", "RCbray") or other options in parameter method of vegan::vegdist function. If the distance matrix has been in the beta_diversity list of microtable object, the function can ignore this step. Otherwise, the function can generate the corresponding beta diversity distance matrix in the microtable object. bray: Bray-Curtis; RCbray: Raup–Crick based Bray-Curtis; wei_unifrac: weighted UniFrac; ses_UniFrac: standardized deviation of UniFrac.

filter_thres

default 0; the relative abundance threshold used to filter features with low abundance.

abundance.weighted

default TRUE; whether use abundance-weighted method for the phylogenetic metrics.

null.model

default NULL; one of c("taxa.labels", "richness", "frequency", "sample.pool", "phylogeny.pool", "independentswap", "trialswap"), in which "taxa.labels" can only be used for phylogenetic analysis. See null.model parameter of ses.mntd function in picante package for the algorithm details.

runs

default 1000; simulation number of times for null model.

iterations

default 1000; iteration number for part null models to perform; see iterations parameter of picante::randomizeMatrix function.

...

parameters passed to cal_betadiv function of microtable class when provided measure is not in the current vector; parameters passed to cal_betamntd function of trans_nullmodel class when measure = "betaMNTD"; parameters passed to cal_ses_betamntd function of trans_nullmodel class when measure = "betaNTI".

Returns

dataset, stored in the object. The new dataset has a beta_diversity list and the calculated distance matrix in the list.

Examples
data(wheat_16S)
b1 <- betaturn$new(wheat_16S, measure = "bray")

Method cal_group_distance()

Convert sample distances within groups or between groups.

Usage
betaturn$cal_group_distance(
  group,
  within_group = TRUE,
  by_group = NULL,
  ordered_group = NULL,
  sep = " vs ",
  add_cols = NULL
)
Arguments
group

one colname of sample_table in microtable object used for group distance convertion.

within_group

default TRUE; whether transform sample distance within groups? If FALSE, transform sample distances between any two groups.

by_group

default NULL; one colname of sample_table in microtable object. If provided, convert distances according to the provided by_group parameter. This is especially useful for ordering and filtering values further. When within_group = TRUE, the result of by_group parameter is the format of paired groups. When within_group = FALSE, the result of by_group parameter is the format same with the group information in sample_table.

ordered_group

default NULL; a vector representing the ordered elements of group parameter; only useful when within_group = FALSE.

sep

default TRUE; a character string to separate the group names after merging them into a new name.

add_cols

default NULL; add several columns of sample_table to the final res_group_distance table according to the by_group column; invoked only when within_group = FALSE.

Returns

res_group_distance stored in object.

Examples
b1$cal_group_distance(group = "Type", within_group = FALSE, by_group = "Plant_ID")

Method cal_group_distance_diff()

Differential test of distances among groups.

Usage
betaturn$cal_group_distance_diff(...)
Arguments
...

parameters passed to cal_group_distance_diff function of trans_beta class.

Returns

res_group_distance_diff stored in object.

Examples
b1$cal_group_distance_diff(method = "wilcox")

Method plot_group_distance()

Plot the distance between samples within or between groups.

Usage
betaturn$plot_group_distance(...)
Arguments
...

parameters passed to plot_group_distance function of trans_beta class.

Returns

ggplot.

Examples
b1$plot_group_distance()

Method clone()

The objects of this class are cloneable with this method.

Usage
betaturn$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

## ------------------------------------------------
## Method `betaturn$new`
## ------------------------------------------------

data(wheat_16S)
b1 <- betaturn$new(wheat_16S, measure = "bray")

## ------------------------------------------------
## Method `betaturn$cal_group_distance`
## ------------------------------------------------

b1$cal_group_distance(group = "Type", within_group = FALSE, by_group = "Plant_ID")

## ------------------------------------------------
## Method `betaturn$cal_group_distance_diff`
## ------------------------------------------------

b1$cal_group_distance_diff(method = "wilcox")

## ------------------------------------------------
## Method `betaturn$plot_group_distance`
## ------------------------------------------------

b1$plot_group_distance()

Analyze the 'turnover' of taxa.

Description

Analyze the 'turnover' of taxa along a defined gradient. The workflow of taxaturn class includes the taxonomic abundance calculation, abundance transformation, abundance change summary, statistical analysis and visualization.

Methods

Public methods


Method new()

Usage
taxaturn$new(
  dataset,
  taxa_level = "Phylum",
  group,
  ordered_group,
  by_ID = NULL,
  by_group = NULL,
  filter_thres = 0
)
Arguments
dataset

the object of microtable class.

taxa_level

default "Phylum"; taxonomic rank name, such as "Genus". An integer is also acceptable. If the provided taxa_level is not found in taxa_abund list, the function will invoke the cal_abund function to obtain the relative abudance automatically.

group

sample group used for the selection; a colname of input microtable$sample_table.

ordered_group

a vector representing the ordered elements of group parameter.

by_ID

default NULL; a column of sample_table used to obtain the consistent change along provided elements. So by_ID can be ID (unique repetition) or even group (with repetitions). If it denotes unique ID, consistent change can be performed across each ID. It is also especially useful for the paired wilcox test (or paired t test) in the following analysis. If it does not represent unique ID, the mean of each group will be calculated, and consistent change across groups will be obtained.

by_group

default NULL; NULL or other colname of sample_table of input dataset used to show the result for different groups; NULL represents the output is the default consistent change across all the elements in by_ID; a colname of sample_table of input dataset means the consistent change is obtained for each group instead of all the elements in by_group; Note that the by_group can be same with by_ID, in which the final change is the result of each element in by_group. So generally by_group has a larger scale than by_ID parameter in terms of the sample numbers in each element.

filter_thres

default 0; the mean abundance threshold used to filter features with low abudance.

Returns

res_abund, res_change_pair and res_change in the object:

res_abund

The Mean, SD or SE of abundances for all the samples or each group. Mean: mean of abudances; SD: standard deviation; SE: standard error.

res_change_pair

The difference value of abudances between two niches, i.e. the latter minus the former.

res_change

The summary of the abudance change results in res_change_pair.

Examples
data(wheat_16S)
t1 <- taxaturn$new(wheat_16S, taxa_level = "Phylum", group = "Type", 
 ordered_group = c("S", "RS", "R"), by_ID = "Plant_ID", filter_thres = 0.01)

Method cal_diff()

Differential test of taxonomic abundance across groups

Usage
taxaturn$cal_diff(
  method = c("wilcox", "t.test", "anova", "betareg", "lme", "glmm")[1],
  group2num = FALSE,
  ...
)
Arguments
method

default "wilcox"; see the following available options:

'wilcox'

Wilcoxon Rank Sum and Signed Rank Tests for all paired groups

't.test'

Student's t-Test for all paired groups

'anova'

one-way or multi-way anova

'betareg'

Beta Regression based on the betareg package

'lme'

lme: Linear Mixed Effect Model based on the lmerTest package

'glmm'

Generalized linear mixed model (GLMM) based on the glmmTMB package with the beta family function, i.e. family = glmmTMB::beta_family(link = "logit"). For more parameters, please see glmmTMB::glmmTMB function. In the return table, Conditional_R2 and Marginal_R2 represent total variance (explained by both fixed and random effects) and the variance explained by fixed effects, respectively. The significance of fixed factors are tested by Chi-square test from function car::Anova. The significance of 'Estimate' in each term of fixed factors comes from the model.

group2num

default FALSE; whether convert ordered groups to integer numbers when method is "lme" or "glmm".

...

parameters passed to trans_diff$new.

Returns

res_change or res_diff in the object.

Examples
t1$cal_diff(method = "wilcox")

Method plot()

Plot the line chart.

Usage
taxaturn$plot(
  select_taxon = NULL,
  color_values = RColorBrewer::brewer.pal(8, "Dark2"),
  delete_prefix = TRUE,
  plot_type = c("point", "line", "errorbar", "smooth")[1:3],
  errorbar_SE = TRUE,
  rect_fill = TRUE,
  rect_color = c("grey70", "grey90"),
  rect_alpha = 0.2,
  position = position_dodge(0.1),
  errorbar_size = 1,
  errorbar_width = 0.1,
  point_size = 3,
  point_alpha = 0.8,
  line_size = 0.8,
  line_alpha = 0.8,
  line_type = 1,
  ...
)
Arguments
select_taxon

default NULL; a taxon name. Note that if delete_prefix is TRUE, the provided select_taxon should be taxa names without long prefix (those before |); if delete_prefix is FALSE, the select_taxon should be full names same with those in the res_abund of the object.

color_values

default RColorBrewer::brewer.pal(8, "Dark2"); colors palette for the plotting.

delete_prefix

default TRUE; whether delete the prefix in the taxa names.

plot_type

default c("point", "line", "errorbar", "smooth")[1:3]; a vector of visualization types. Multiple elements are available. 'smooth' denotes the fitting with geom_smooth function of ggplot2 package.

errorbar_SE

default TRUE; TRUE: plot the errorbar with mean ± se; FALSE: plot the errorbar with mean ± sd.

rect_fill

default TRUE; Whether fill color in each rectangular area.

rect_color

default c("grey70", "grey90"); the colors used to fill different rectangular area.

rect_alpha

default 0.2; the fill color transparency in rectangular area.

position

default position_dodge(0.1); Position adjustment for the points and lines, either as a string (such as "identity"), or the result of a call to a position adjustment function.

errorbar_size

default 1; errorbar size.

errorbar_width

default 0.1; errorbar width.

point_size

default 3; point size for taxa.

point_alpha

default 0.8; point transparency.

line_size

default 0.8; line size.

line_alpha

default 0.8; line transparency.

line_type

default 1; an integer; line type.

...

parameters passed to geom_smooth when 'smooth' is in plot_type parameter.

Returns

ggplot2 plot.

Examples
t1$plot()

Method clone()

The objects of this class are cloneable with this method.

Usage
taxaturn$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

## ------------------------------------------------
## Method `taxaturn$new`
## ------------------------------------------------

data(wheat_16S)
t1 <- taxaturn$new(wheat_16S, taxa_level = "Phylum", group = "Type", 
 ordered_group = c("S", "RS", "R"), by_ID = "Plant_ID", filter_thres = 0.01)

## ------------------------------------------------
## Method `taxaturn$cal_diff`
## ------------------------------------------------

t1$cal_diff(method = "wilcox")

## ------------------------------------------------
## Method `taxaturn$plot`
## ------------------------------------------------

t1$plot()

The example dataset in the mecoturn package

Description

The dataset wheat_16S is structured with microtable class for the demonstration of examples.

Usage

data(wheat_16S)

Format

An R6 class object

Details

  • sample_table: sample information table

  • otu_table: species-community abundance table

  • tax_table: taxonomic table

  • phylo_tree: phylogenetic tree