DATASET_ALIGNMENT

Weiyue Liu1, Zhongyi Hua2, Tong Zhou3

Last compiled on 07 December, 2023

Introduction

The function of the DATASET_ALIGNMENT is to display multiple sequence alignments (MSA) next to the leaf node. Consensus sequence (at 50% conservation) and conserved residues will be calculated automatically. The DATASET_ALIGNMENT template belongs to the “Advanced Graphics” class (refer to the Class for detail information).

visualize multiple sequence alignments

This section provides an example of how to visualize multiple sequence alignments using dataset 1 (refer to the Dataset for detail information) document for detailed information).

The first step is to load the newick format tree file tree_of_itol_templates.tree and its corresponding metadata parameter_groups.txt. The parameter_groups.txt file contains the type of each parameter and the parameters contained in each template.

library(itol.toolkit)
library(data.table)
library(dplyr)
library(tidyr)
tree <- system.file("extdata",
                    "tree_of_itol_templates.tree",
                    package = "itol.toolkit")
parameter_groups <- system.file("extdata",
                                "parameter_groups.txt",
                                package = "itol.toolkit")

In practice, the user needs to prepare the input file as the following format: the first column should be the tips of the tree, and the second column should be the sequence after multiple sequence aligning. The leaf node name in tree_of_itol_templates.tree is template names. Here, we generate a sequence for each tip based on the types of it corresponding template parameters. These sequences are used to simulate the MSA result.

tab_tmp <- fread(parameter_groups)
tab_id_group <- tab_tmp[, c(1,2)]
tab_tmp <- tab_tmp[, -c(1,2)]
tab_tmp_01 <- convert_01(object = tab_tmp)
tab_tmp_01 <- cbind(tab_id_group, tab_tmp_01)
order <- c("type",
           "separator",
           "profile",
           "field",
           "common themes",
           "specific themes",
           "data")
tab_tmp_01_long <- tab_tmp_01 %>%
                   melt(id.vars=c("parameter","group"))
template_start_group <- tab_tmp_01_long %>%
                        group_by(group,variable) %>%
                        summarise(sublen = sum(value)) %>%
                        tidyr::spread(key=variable,value=sublen)
template_start_group$group <- factor(template_start_group$group,levels = order)
template_start_group <- template_start_group %>%
                        arrange(group)
start_group <- data.frame(Var1 = template_start_group$group, Freq = apply(template_start_group[,-1], 1, max))
start_group$start <- 0
for (i in 2:nrow(start_group)) {
    start_group$start[i] <- sum(start_group$Freq[1:(i-1)])
}
# Just simulate MSA as example, not necessary for real run
template_start_group <- as.data.frame(t(template_start_group))
colnames(template_start_group) <- template_start_group[1,]
template_start_group <- template_start_group[-1,]
template_start_group[template_start_group == 0] <- "--"
template_start_group[template_start_group == " 0"] <- "--"
template_start_group$type[template_start_group$type != "--"] <- "AA"
template_start_group$separator[template_start_group$separator != "--"] <- "TT"
template_start_group$profile[template_start_group$profile != "--"] <- "GG"
template_start_group$field[template_start_group$field != "--"] <- "CC"
template_start_group$`common themes`[template_start_group$`common themes` != "--"] <- "AT"
template_start_group$`specific themes`[template_start_group$`specific themes` != "--"] <- "GC"
template_start_group$data[template_start_group$data != "--"] <- "TG"
template_start_group <- template_start_group %>%
                        mutate(id = rownames(template_start_group)) %>%
                        tidyr::unite("seq",type:data,remove = T, sep = "") %>%
                        select(id,seq)

The processed data is stored in the variable template_start_group, with the first column being the template name and the second column being the sequence.

unit_32 <- create_unit(data = template_start_group,
                       key = "E032_ALIGNMENT_1",
                       type = "DATASET_ALIGNMENT",
                       tree = tree)

Style modification

Consensus sequence

The threshold for consensus calculation can be set by the unit@specific_themes$alignment$consensus$threshold variable (0 ~ 100). To ignore any gaps in the alignment when calculating the consensus, set unit@specific_themes$alignment$gap$ignore to 1.

Residues and reference sequences

Residues in the alignment can be highlighted as dots by setting the unit@specific_themes$alignment$highlight$type. When set to consensus, each residue will be displayed as a dot if it does not match the consensus sequence. When unit@specific_themes$alignment$highlight$type is set to reference, residues will be compared to the reference sequences defined in unit@specific_themes$alignment$reference$ids. When unit@specific_themes$alignment$reference$ids defined, reference sequences can be marked with boxes by setting unit@specific_themes$alignment$reference$use to 1.

  1. IOCAS, ↩︎

  2. CACMS, ↩︎

  3. IOCAS, ↩︎