Bios2cor (version 2.1)

import.fasta: Reads a file in FASTA format

Description

Reads a Multiple Sequence Alignment (MSA) file in FASTA format (.fasta or .fa extension).

Usage

import.fasta(file, aa.to.upper = TRUE, gap.to.dash = TRUE, log.file = NULL)

Arguments

file

a string of characters to indicate the name of the MSA file to be read.

aa.to.upper

a logical value indicating whether amino acids should be converted to upper case (TRUE) or not (FALSE). Default is TRUE.

gap.to.dash

a logical value indicating whether the dot (.) and tilde (\(\sim\)) gap symbols should be converted to dash (-) character (TRUE) or not (FALSE). Default is TRUE.

log.file

a file containing errors that occurred when trying to read fasta file

Value

A object of class 'align', which is a named list whose elements correspond to sequences, in the form of character vectors.

Details

Initially, FASTA (for FAST-ALL) was the input format of the FASTA program, used for protein comparison and searching in databases. Presently, FASTA format is a standard format for biological sequences.

The FASTA formatted file of a single sequence displays:

• a single-line description beginning with a greater-than (>) symbol. The following word is the identifier.

• followed by any number of lines, representing biological sequence.

For multiple alignments, the FASTA formatted sequences are concatenated to create a multiple FASTA format.

References

Pearson WR and Lipman DJ (1988) Improved tools for biological sequence comparison. Proc Natl Acad Sci U S A 27:2444-2448.

Examples

# NOT RUN {
  # Importing MSA file in FASTA format
  aln <- import.fasta(system.file("msa/toy2_align.fa", package = "Bios2cor"))
# }