Assignment: Your assignment is to use your notes from class - along with help from classmates, UTAs, and me - to turn this script into a fleshed-out description of what is going on.

This is a substantial project - we’ll work on it in steps over the rest of the unit.

We are currently focused on the overall process and will cover the details over the rest of this unit.

Your first assignment is to get this script to run from top to bottom by adding all of the missing R commands. Once you have done that, you can knit it into an HTML file and upload it to RPubs. (Note - you’ll need to add the YAML header!)

Your second assignment, which will be posted later, is to answer all the TODO and other prompts to add information. You can start on this, but you don’t have to do this on your first time through the code.

Delete all the prompts like TODO() as you compete them. Use RStudio’s search function to see if you’ve missed any - there are a LOT!

Add YAML header!!! Give it a title

A complete bioinformatics workflow in R

By: Nathan L. Brouwer

“Worked example: Building a phylogeny in R”

Introduction

Describe how phylogeneies can be used in biology (readings will be assigned)

Phylogenies compare different species and their evolution, allowing us to decipher if species are closely related or not. We will use multiple sequence alignments to compare various amino acid sequences, which will allow us to view the similarity of the sequences.

Vocab

Make a list of at least 10 vocab terms that are important (don’t have to define) - FASTA - indel - node - wrapper - homology - consensus sequence - alignment - entrez - expressed sequence tags - accession

Key functions

rentrez::entrez_fetch() compbio4all::entez_fetch_list() Biostrings::pairwiseAlignment() Biostrings::pid() Biostrings::AAStringSet()

Software Preliminaires

Add the necessary calls to library() to load call packages Indicate which packages cam from Bioconducotr, CRAN, and GitHub

Load packages into memory

# github packages
library(compbio4all)
library(ggmsa)


# CRAN packages
library(devtools)
library(BiocManager)
library(rentrez)
library(seqinr)
library(ape)

# Bioconductor packages

library(Biostrings)
#library(msa)

Retrieving macromolecular sequences

The amino acid sequence of Human shroom 3 is being retrieved from the NCBI database.

# Human shroom 3 (H. sapiens)
hShroom3 <- rentrez::entrez_fetch(db = "protein", 
                          id = "NP_065910", 
                          rettype = "fasta")

cat converts its arguments to character strings, concatenates them, and prints them back out.

cat(hShroom3)
## >NP_065910.3 protein Shroom3 [Homo sapiens]
## MMRTTEDFHKPSATLNSNTATKGRYIYLEAFLEGGAPWGFTLKGGLEHGEPLIISKVEEGGKADTLSSKL
## QAGDEVVHINEVTLSSSRKEAVSLVKGSYKTLRLVVRRDVCTDPGHADTGASNFVSPEHLTSGPQHRKAA
## WSGGVKLRLKHRRSEPAGRPHSWHTTKSGEKQPDASMMQISQGMIGPPWHQSYHSSSSTSDLSNYDHAYL
## RRSPDQCSSQGSMESLEPSGAYPPCHLSPAKSTGSIDQLSHFHNKRDSAYSSFSTSSSILEYPHPGISGR
## ERSGSMDNTSARGGLLEGMRQADIRYVKTVYDTRRGVSAEYEVNSSALLLQGREARASANGQGYDKWSNI
## PRGKGVPPPSWSQQCPSSLETATDNLPPKVGAPLPPARSDSYAAFRHRERPSSWSSLDQKRLCRPQANSL
## GSLKSPFIEEQLHTVLEKSPENSPPVKPKHNYTQKAQPGQPLLPTSIYPVPSLEPHFAQVPQPSVSSNGM
## LYPALAKESGYIAPQGACNKMATIDENGNQNGSGRPGFAFCQPLEHDLLSPVEKKPEATAKYVPSKVHFC
## SVPENEEDASLKRHLTPPQGNSPHSNERKSTHSNKPSSHPHSLKCPQAQAWQAGEDKRSSRLSEPWEGDF
## QEDHNANLWRRLEREGLGQSLSGNFGKTKSAFSSLQNIPESLRRHSSLELGRGTQEGYPGGRPTCAVNTK
## AEDPGRKAAPDLGSHLDRQVSYPRPEGRTGASASFNSTDPSPEEPPAPSHPHTSSLGRRGPGPGSASALQ
## GFQYGKPHCSVLEKVSKFEQREQGSQRPSVGGSGFGHNYRPHRTVSTSSTSGNDFEETKAHIRFSESAEP
## LGNGEQHFKNGELKLEEASRQPCGQQLSGGASDSGRGPQRPDARLLRSQSTFQLSSEPEREPEWRDRPGS
## PESPLLDAPFSRAYRNSIKDAQSRVLGATSFRRRDLELGAPVASRSWRPRPSSAHVGLRSPEASASASPH
## TPRERHSVTPAEGDLARPVPPAARRGARRRLTPEQKKRSYSEPEKMNEVGIVEEAEPAPLGPQRNGMRFP
## ESSVADRRRLFERDGKACSTLSLSGPELKQFQQSALADYIQRKTGKRPTSAAGCSLQEPGPLRERAQSAY
## LQPGPAALEGSGLASASSLSSLREPSLQPRREATLLPATVAETQQAPRDRSSSFAGGRRLGERRRGDLLS
## GANGGTRGTQRGDETPREPSSWGARAGKSMSAEDLLERSDVLAGPVHVRSRSSPATADKRQDVLLGQDSG
## FGLVKDPCYLAGPGSRSLSCSERGQEEMLPLFHHLTPRWGGSGCKAIGDSSVPSECPGTLDHQRQASRTP
## CPRPPLAGTQGLVTDTRAAPLTPIGTPLPSAIPSGYCSQDGQTGRQPLPPYTPAMMHRSNGHTLTQPPGP
## RGCEGDGPEHGVEEGTRKRVSLPQWPPPSRAKWAHAAREDSLPEESSAPDFANLKHYQKQQSLPSLCSTS
## DPDTPLGAPSTPGRISLRISESVLRDSPPPHEDYEDEVFVRDPHPKATSSPTFEPLPPPPPPPPSQETPV
## YSMDDFPPPPPHTVCEAQLDSEDPEGPRPSFNKLSKVTIARERHMPGAAHVVGSQTLASRLQTSIKGSEA
## ESTPPSFMSVHAQLAGSLGGQPAPIQTQSLSHDPVSGTQGLEKKVSPDPQKSSEDIRTEALAKEIVHQDK
## SLADILDPDSRLKTTMDLMEGLFPRDVNLLKENSVKRKAIQRTVSSSGCEGKRNEDKEAVSMLVNCPAYY
## SVSAPKAELLNKIKEMPAEVNEEEEQADVNEKKAELIGSLTHKLETLQEAKGSLLTDIKLNNALGEEVEA
## LISELCKPNEFDKYRMFIGDLDKVVNLLLSLSGRLARVENVLSGLGEDASNEERSSLYEKRKILAGQHED
## ARELKENLDRRERVVLGILANYLSEEQLQDYQHFVKMKSTLLIEQRKLDDKIKLGQEQVKCLLESLPSDF
## IPKAGALALPPNLTSEPIPAGGCTFSGIFPTLTSPL

This code chunk is retrieving the amino acid sequences of mouse shroom 3a, human shroom 2, and sea-urchin shroom.

# Mouse shroom 3a (M. musculus)
mShroom3a <- entrez_fetch(db = "protein", 
                          id = "AAF13269", 
                          rettype = "fasta")

# Human shroom 2 (H. sapiens)
hShroom2 <- entrez_fetch(db = "protein", 
                          id = "CAA58534", 
                          rettype = "fasta")


# Sea-urchin shroom
sShroom <- entrez_fetch(db = "protein", 
                          id = "XP_783573", 
                          rettype = "fasta")

This chunk of code returns the number of amino acids in each of the sequences.

nchar(hShroom3)
## [1] 2070
nchar(mShroom3a)
## [1] 2083
nchar(sShroom)
## [1] 1758
nchar(hShroom2)
## [1] 1673

Prepping macromolecular sequences

This function converts a FASTA file stored as an object into a vector and cleans it by deleting unnecessary characters which are not apart of the sequence.

fasta_cleaner
## function (fasta_object, parse = TRUE) 
## {
##     fasta_object <- sub("^(>)(.*?)(\\n)(.*)(\\n\\n)", "\\4", 
##         fasta_object)
##     fasta_object <- gsub("\n", "", fasta_object)
##     if (parse == TRUE) {
##         fasta_object <- stringr::str_split(fasta_object, pattern = "", 
##             simplify = FALSE)
##     }
##     return(fasta_object[[1]])
## }
## <bytecode: 0x7fe6d333a9e8>
## <environment: namespace:compbio4all>

If you don’t load a package into your library, you can use compbio4all::function notation to use the function.

fasta_cleaner <- function(fasta_object, parse = TRUE){

  fasta_object <- sub("^(>)(.*?)(\\n)(.*)(\\n\\n)","\\4",fasta_object)
  fasta_object <- gsub("\n", "", fasta_object)

  if(parse == TRUE){
    fasta_object <- stringr::str_split(fasta_object,
                                       pattern = "",
                                       simplify = FALSE)
  }

  return(fasta_object[[1]])
}

This chunk is cleaning out all of the sequences we have downloaded but not parsing the data to a character vector

hShroom3  <- fasta_cleaner(hShroom3,  parse = F)
mShroom3a <- fasta_cleaner(mShroom3a, parse = F)
hShroom2  <- fasta_cleaner(hShroom2,  parse = F)
sShroom   <- fasta_cleaner(sShroom,   parse = F)

Doing pairwise alignment of sequences

Lines up sequences of different proteins and compares where the sequence is the same or different

# add necessary function
align.h3.vs.m3a <- Biostrings::pairwiseAlignment(
                  hShroom3,
                  mShroom3a)

This prints the matched sequences of the objects/

align.h3.vs.m3a
## Global PairwiseAlignmentsSingleSubject (1 of 1)
## pattern: MMRTTEDFHKPSATLN-SNTATKGRYIYLEAFLE...KAGALALPPNLTSEPIPAGGCTFSGIFPTLTSPL
## subject: MK-TPENLEEPSATPNPSRTPTE-RFVYLEALLE...KAGAISLPPALTGHATPGGTSVFGGVFPTLTSPL
## score: 2189.934

This shows the percent identity, the simplest way of comparing two sequences by going down the sequence and calculating the number of the same amino acids/total length of amino acids.

# add necessary function
Biostrings::pid(align.h3.vs.m3a)
## [1] 70.56511

Aligns the amino acid sequences of human shroom 3 and 2.

align.h3.vs.h2 <- Biostrings::pairwiseAlignment(
                  hShroom3,
                  hShroom2)

Gives a “score”, where more positive is good and more negative is not. The score does not have an intrinsic value - it is just used for comparison purposes.

score(align.h3.vs.h2)
## [1] -5673.853

Score is much more complicated than PID and is used mainly for comparing sequences. Pid finds the percent match of two samples, and is much more straight forward.

Biostrings::pid(align.h3.vs.h2)
## [1] 33.83277

The shroom family of genes

Set up a data frame of various shroom genes, with information including the accession numbers, and the original and new gene names.

shroom_table <- c("CAA78718" , "X. laevis Apx" ,         "xShroom1",
            "NP_597713" , "H. sapiens APXL2" ,     "hShroom1",
            "CAA58534" , "H. sapiens APXL",        "hShroom2",
            "ABD19518" , "M. musculus Apxl" ,      "mShroom2",
            "AAF13269" , "M. musculus ShroomL" ,   "mShroom3a",
            "AAF13270" , "M. musculus ShroomS" ,   "mShroom3b",
            "NP_065910", "H. sapiens Shroom" ,     "hShroom3",
            "ABD59319" , "X. laevis Shroom-like",  "xShroom3",
            "NP_065768", "H. sapiens KIAA1202" ,   "hShroom4a",
            "AAK95579" , "H. sapiens SHAP-A" ,     "hShroom4b",
            #"DQ435686" , "M. musculus KIAA1202" ,  "mShroom4",
            "ABA81834" , "D. melanogaster Shroom", "dmShroom",
            "EAA12598" , "A. gambiae Shroom",      "agShroom",
            "XP_392427" , "A. mellifera Shroom" ,  "amShroom",
            "XP_783573" , "S. purpuratus Shroom" , "spShroom") #sea urchin

Taking raw data and making it into a neater, nicer table

# convert to matrix
shroom_table_matrix <- matrix(shroom_table,
                                  byrow = T,
                                  nrow = 14)
# convert to data frame
shroom_table <- data.frame(shroom_table_matrix, 
                     stringsAsFactors = F)

# namiing columns
names(shroom_table) <- c("accession", "name.orig","name.new")

# Create simplified species names
shroom_table$spp <- "Homo"
shroom_table$spp[grep("laevis",shroom_table$name.orig)] <- "Xenopus"
shroom_table$spp[grep("musculus",shroom_table$name.orig)] <- "Mus"
shroom_table$spp[grep("melanogaster",shroom_table$name.orig)] <- "Drosophila"
shroom_table$spp[grep("gambiae",shroom_table$name.orig)] <- "mosquito"
shroom_table$spp[grep("mellifera",shroom_table$name.orig)] <- "bee"
shroom_table$spp[grep("purpuratus",shroom_table$name.orig)] <- "sea urchin"

Displays the neat and organized table we just created

shroom_table
##    accession              name.orig  name.new        spp
## 1   CAA78718          X. laevis Apx  xShroom1    Xenopus
## 2  NP_597713       H. sapiens APXL2  hShroom1       Homo
## 3   CAA58534        H. sapiens APXL  hShroom2       Homo
## 4   ABD19518       M. musculus Apxl  mShroom2        Mus
## 5   AAF13269    M. musculus ShroomL mShroom3a        Mus
## 6   AAF13270    M. musculus ShroomS mShroom3b        Mus
## 7  NP_065910      H. sapiens Shroom  hShroom3       Homo
## 8   ABD59319  X. laevis Shroom-like  xShroom3    Xenopus
## 9  NP_065768    H. sapiens KIAA1202 hShroom4a       Homo
## 10  AAK95579      H. sapiens SHAP-A hShroom4b       Homo
## 11  ABA81834 D. melanogaster Shroom  dmShroom Drosophila
## 12  EAA12598      A. gambiae Shroom  agShroom   mosquito
## 13 XP_392427    A. mellifera Shroom  amShroom        bee
## 14 XP_783573   S. purpuratus Shroom  spShroom sea urchin

Comparing multiple sequences

The $ allows us to access data of specific categories from a data table. In this case, we can access the accession numbers from the shroom_table

shroom_table$accession
##  [1] "CAA78718"  "NP_597713" "CAA58534"  "ABD19518"  "AAF13269"  "AAF13270" 
##  [7] "NP_065910" "ABD59319"  "NP_065768" "AAK95579"  "ABA81834"  "EAA12598" 
## [13] "XP_392427" "XP_783573"

Creates an object with all 14 sequences.

# add necessary function
shrooms <- rentrez::entrez_fetch(db = "protein", 
                          id = shroom_table$accession, 
                          rettype = "fasta")

Enforces new line code - formats it as if it were a text file and prints it to your R console

cat(shrooms)

Wrapper function: an edited version of entrez_fetch function entrez_fetch is a dependency of compbio4all

shrooms_list <- entrez_fetch_list(db = "protein", 
                          id = shroom_table$accession, 
                          rettype = "fasta")

is(shrooms_list)
## [1] "list"             "vector"           "list_OR_List"     "vector_OR_Vector"
## [5] "vector_OR_factor"
length(shrooms_list)
## [1] 14
nchar(shrooms_list)
##  CAA78718 NP_597713  CAA58534  ABD19518  AAF13269  AAF13270 NP_065910  ABD59319 
##      1486       915      1673      1543      2083      1895      2070      1864 
## NP_065768  AAK95579  ABA81834  EAA12598 XP_392427 XP_783573 
##      1560       778      1647       750      2230      1758

Prints out the length of the new shrooms_list

length(shrooms_list)
## [1] 14

Clean up the sequences in the shrooms_list by looping through them

for(i in 1:length(shrooms_list)){
  shrooms_list[[i]] <- fasta_cleaner(shrooms_list[[i]], parse = F)
}

Convert shrooms_list into a vector

# Create an empty vector of length of shrooms_list
shrooms_vector <- rep(NA, length(shrooms_list))

# Lopp through the vector, copy each sequence of shrooms_list into shrooms_vector
for(i in 1:length(shrooms_vector)){
  shrooms_vector[i] <- shrooms_list[[i]]
}

#Put the accession numbers of the shrooms_list into new vector
names(shrooms_vector) <- names(shrooms_list)

Convert the vector into a string set - final step of cleaning up our sequences

# add necessary function
shrooms_vector_ss <- Biostrings::AAStringSet(shrooms_vector)

MSA

This section will build our MSA so we can compare various amino acid sequences

Building an alignment (MSA)

Convert our sequences from string set into a msa

# add necessary function
library(msa)
## 
## Attaching package: 'msa'
## The following object is masked from 'package:BiocManager':
## 
##     version
shrooms_align <- msa(shrooms_vector_ss,
                     method = "ClustalW")
## use default substitution matrix

Viewing an MSA

Create and output an organized MSA (miltiple sequence alignment)

Viewing an MSA in R

Outputs our shrooms_align MSA

shrooms_align
## CLUSTAL 2.1  
## 
## Call:
##    msa(shrooms_vector_ss, method = "ClustalW")
## 
## MsaAAMultipleAlignment with 14 rows and 2252 columns
##      aln                                                   names
##  [1] -------------------------...------------------------- NP_065768
##  [2] -------------------------...------------------------- AAK95579
##  [3] -------------------------...SVFGGVFPTLTSPL----------- AAF13269
##  [4] -------------------------...SVFGGVFPTLTSPL----------- AAF13270
##  [5] -------------------------...CTFSGIFPTLTSPL----------- NP_065910
##  [6] -------------------------...NKS--LPPPLTSSL----------- ABD59319
##  [7] -------------------------...------------------------- CAA58534
##  [8] -------------------------...------------------------- ABD19518
##  [9] -------------------------...LT----------------------- NP_597713
## [10] -------------------------...------------------------- CAA78718
## [11] -------------------------...------------------------- EAA12598
## [12] -------------------------...------------------------- ABA81834
## [13] MTELQPSPPGYRVQDEAPGPPSCPP...------------------------- XP_392427
## [14] -------------------------...AATSSSSNGIGGPEQLNSNATSSYC XP_783573
##  Con -------------------------...------------------------- Consensus

Get shrooms_align to the desired form: seqinr::alignment

#Set the class on shrooms_align inherits from, AAMultipleAlignment
class(shrooms_align) <- "AAMultipleAlignment"

#Converts shrooms_align to the type seqinr::alignment
shrooms_align_seqinr <- msaConvert(shrooms_align, type = "seqinr::alignment")

Prints the MSA

print_msa(alignment = shrooms_align_seqinr, chunksize = 60)

Displaying an MSA XXXXXXXX

Print out the MSA in a neater, nicer fashion

## add necessary function
ggmsa::ggmsa(shrooms_align,   # shrooms_align, NOT shrooms_align_seqinr
      start = 2000, 
      end = 2100) 

Saving an MSA as PDF

Save the MSA to a file

msa::msaPrettyPrint(shrooms_align,             # alignment
               file = "shroom_msa.pdf",   # file name
               y=c(2000, 2100),           # range
               askForOverwrite=FALSE)

Print the path to where the MSA is saved

getwd()
## [1] "/Users/ginawang/Desktop/currentclasses/biosc 1540"