I have a long data frame of genes and various forms of ids for them (e.g. OMIM, Ensembl, Genatlas). I want to get the list of all SNPs that are associated with each gene. (This is the reverse of this question.)
So far, the best solution I have found is using the biomaRt package (bioconductor). There is an example of the kind of lookup I need to do here. Fitted for my purposes, here is my code:
library(biomaRt)
#load the human variation data
variation = useEnsembl(biomart="snp", dataset="hsapiens_snp")
#look up a single gene and get SNP data
getBM(attributes = c(
"ensembl_gene_stable_id",
'refsnp_id',
'chr_name',
'chrom_start',
'chrom_end',
'minor_allele',
'minor_allele_freq'),
filters = 'ensembl_gene',
values ="ENSG00000166813",
mart = variation
)
This outputs a data frame that begins like this:
ensembl_gene_stable_id refsnp_id chr_name chrom_start chrom_end minor_allele minor_allele_freq
1 ENSG00000166813 rs8179065 15 89652777 89652777 T 0.242412
2 ENSG00000166813 rs8179066 15 89652736 89652736 C 0.139776
3 ENSG00000166813 rs12899599 15 89629243 89629243 A 0.121006
4 ENSG00000166813 rs12899845 15 89621954 89621954 C 0.421126
5 ENSG00000166813 rs12900185 15 89631884 89631884 A 0.449681
6 ENSG00000166813 rs12900805 15 89631593 89631593 T 0.439297
(4612 rows)
The code works, but the running time is extremely long. For the above, it takes about 45 seconds. I thought maybe this was related to the allele frequencies, which the server perhaps calculated on the fly. But looking up the bare minimum of only the SNPs rs ids takes something like 25 seconds. I have a few thousand genes, so this would take an entire day (assuming no timeouts or other errors). This can't be right. My internet connection is not slow (20-30 mbit).
I tried looking up more genes per query. This did dot help. Looking up 10 genes at once is roughly 10 times as slow as looking up a single gene.
What is the best way to get a vector of SNPs that associated with a vector of gene ids?
If I could just download two tables, one with genes and their positions and one with SNPs and their positions, then I could easily solve this problem using dplyr (or maybe data.table). I haven't been able to find such tables.
Since you're using R, here's an idea that uses the package rentrez. It utilizes NCBI's Entrez database system and in particular the eutils function, elink. You'll have to write some code around this and probably tweak parameters, but could be a good start.
library(rentrez)
# for converting gene name -> gene id
gene_search <- entrez_search(db="gene", term="(PTEN[Gene Name]) AND Homo sapiens[Organism]", retmax=1)
geneId <- gene_search$ids
# elink function
snp_links <- entrez_link(dbfrom='gene', id=geneId, db='snp')
# access results with $links
length(snp_links$links$gene_snp)
5779
head(snp_links$links$gene_snp)
'864622690' '864622594' '864622518' '864622451' '864622387' '864622341'
I suggest you manually double-check that the number of SNPs is about what you'd expect for your genes of interest -- you may need to drill down further and limit by transcript, etc...
For multiple gene ids:
multi_snp_links <- entrez_link(dbfrom='gene', id=c("5728", "374654"), db='snp', by_id=TRUE)
lapply(multi_snp_links, function(x) head(x$links$gene_snp))
1. '864622690' '864622594' '864622518' '864622451' '864622387' '864622341'
2. '797045093' '797044466' '797044465' '797044464' '797044463' '797016353'
The results are grouped by gene with by_id=TRUE
Related
I am new to R (and coding in general) and am really stuck on how to approach this problem.
I have a very large data set; columns are sample ID# (~7000 samples) and rows are gene expression (~20,000 genes). Column headings are BIOPSY1-A, BIOPSY1-B, BIOPSY1-C, ..., BIOPSY200-Z. Each number (1-200) is a different patient, and each sample for that patient is a different letter (-A, -Z).
I would like to do some comparisons between samples that came from men and women. Gender is not included in this gene expression table. I have a separate file with patient numbers (BIOPSY1-200) and their gender M/F.
I would like to code something that will look at the column ID (ex: BIOPSY7-A), recognize that it includes "BIOPSY7" (but not == BIOPSY7 because there is BIOPSY7-A through BIOPSY7-Z), find "BIOPSY7" in the reference file, extrapolate M/F, and create a new row with M/F designation.
Honestly, I am so overwhelmed with coding this that I tried to open the file in Excel to manually input M/F, for the 7000 columns as it would probably be faster. However, the file is so large that Excel crashes when it opens.
Any input or resources that would put me on the right path would be extremely appreciated!!
I don't quite know how your data looks like, so I made mine based on your definitions. I'm sure you can modify this answer based on your needs and your dataset structure:
library(data.table)
genderfile <-data.frame("ID"=c("BIOPSY1", "BIOPSY2", "BIOPSY3", "BIOPSY4", "BIOPSY5"),"Gender"=c("F","M","M","F","M"))
#you can just read in your gender file to r with the line below
#genderfile <- read.csv("~/gender file.csv")
View(genderfile)
df<-matrix(rnorm(45, mean=10, sd=5),nrow=3)
colnames(df)<-c("BIOPSY1-A", "BIOPSY1-B", "BIOPSY1-C", "BIOPSY2-A", "BIOPSY2-B", "BIOPSY2-C","BIOPSY3-A", "BIOPSY3-B", "BIOPSY3-C","BIOPSY4-A", "BIOPSY4-B", "BIOPSY4-C","BIOPSY5-A", "BIOPSY5-B", "BIOPSY5-C")
df<-cbind(Gene=seq(1:3),df)
df<-as.data.frame(df)
#you can just read in your main df to r with the line below, fread prevents dashes to turn to period in r, you need data.table package installed and checked in
#df<-fread("~/first file.csv")
View(df)
Note that the following line of code removes the dash and letter from the column names of df (I removed the first column by df[,-c(1)] because it is the Gene id):
substr(x=names(df[,-c(1)]),start=1,stop=nchar(names(df[,-c(1)]))-2)
#[1] "BIOPSY1" "BIOPSY1" "BIOPSY1" "BIOPSY2" "BIOPSY2" "BIOPSY2" "BIOPSY3" "BIOPSY3" "BIOPSY3" "BIOPSY4" "BIOPSY4"
#[12] "BIOPSY4" "BIOPSY5" "BIOPSY5" "BIOPSY5"
Now, we are ready to match the columns of df with the ID in genderfile to get the Gender column:
Gender<-genderfile[, "Gender"][match(substr(x=names(df[,-c(1)]),start=1,stop=nchar(names(df[,-c(1)]))-2), genderfile[,"ID"])]
Gender
#[1] F F F M M M M M M F F F M M M
Last step is to add the Gender defined above as a row to the df:
df_withGender<-rbind(c("Gender", as.character(Gender)), df)
View(df_withGender)
I am very new with the GO analysis and I am a bit confuse how to do it my list of genes.
I have a list of genes (n=10):
gene_list
SYMBOL ENTREZID GENENAME
1 AFAP1 60312 actin filament associated protein 1
2 ANAPC11 51529 anaphase promoting complex subunit 11
3 ANAPC5 51433 anaphase promoting complex subunit 5
4 ATL2 64225 atlastin GTPase 2
5 AURKA 6790 aurora kinase A
6 CCNB2 9133 cyclin B2
7 CCND2 894 cyclin D2
8 CDCA2 157313 cell division cycle associated 2
9 CDCA7 83879 cell division cycle associated 7
10 CDCA7L 55536 cell division cycle associated 7-like
and I simply want to find their function and I've been suggested to use GO analysis tools.
I am not sure if it's a correct way to do so.
here is my solution:
x <- org.Hs.egGO
# Get the entrez gene identifiers that are mapped to a GO ID
xx<- as.list(x[gene_list$ENTREZID])
So, I've got a list with EntrezID that are assigned to several GO terms for each genes.
for example:
> xx$`60312`
$`GO:0009966`
$`GO:0009966`$GOID
[1] "GO:0009966"
$`GO:0009966`$Evidence
[1] "IEA"
$`GO:0009966`$Ontology
[1] "BP"
$`GO:0051493`
$`GO:0051493`$GOID
[1] "GO:0051493"
$`GO:0051493`$Evidence
[1] "IEA"
$`GO:0051493`$Ontology
[1] "BP"
My question is :
how can I find the function for each of these genes in a simpler way and I also wondered if I am doing it right or?
because I want to add the function to the gene_list as a function/GO column.
Thanks in advance,
EDIT: There is a new Bioinformatics SE (currently in beta mode).
I hope I get what you are aiming here.
BTW, for bioinformatics related topics, you can also have a look at biostar which have the same purpose as SO but for bioinformatics
If you just want to have a list of each function related to the gene, you can query database such ENSEMBl through the biomaRt bioconductor package which is an API for querying biomart database.
You will need internet though to do the query.
Bioconductor proposes packages for bioinformatics studies and these packages come generally along with good vignettes which get you through the different steps of the analysis (and even highlight how you should design your data or which would be then some of the pitfalls).
In your case, directly from biomaRt vignette - task 2 in particular:
Note: there are slightly quicker way that the one I reported below:
# load the library
library("biomaRt")
# I prefer ensembl so that the one I will query, but you can
# query other bases, try out: listMarts()
ensembl=useMart("ensembl")
# as it seems that you are looking for human genes:
ensembl = useDataset("hsapiens_gene_ensembl",mart=ensembl)
# if you want other model organisms have a look at:
#listDatasets(ensembl)
You need to create your query (your list of ENTREZ ids). To see which filters you can query:
filters = listFilters(ensembl)
And then you want to retrieve attributes : your GO number and description. To see the list of available attributes
attributes = listAttributes(ensembl)
For you, the query would look like something as:
goids = getBM(
#you want entrezgene so you know which is what, the GO ID and
# name_1006 is actually the identifier of 'Go term name'
attributes=c('entrezgene','go_id', 'name_1006'),
filters='entrezgene',
values=gene_list$ENTREZID,
mart=ensembl)
The query itself can take a while.
Then you can always collapse the information in two columns (but I won't recommend it for anything else that reporting purposes).
Go.collapsed<-Reduce(rbind,lapply(gene_list$ENTREZID,function(x)
tempo<-goids[goids$entrezgene==x,]
return(
data.frame('ENTREZGENE'= x,
'Go.ID'= paste(tempo$go_id,collapse=' ; '),
'GO.term'=paste(tempo$name_1006,collapse=' ; '))
)
Edit:
If you want to query a past version of the ensembl database:
ens82<-useMart(host='sep2015.archive.ensembl.org',
biomart='ENSEMBL_MART_ENSEMBL',
dataset='hsapiens_gene_ensembl')
and then the query would be:
goids = getBM(attributes=c('entrezgene','go_id', 'name_1006'),
filters='entrezgene',values=gene_list$ENTREZID,
mart=ens82)
However, if you had in mind to do a GO enrichment analysis, your list of genes is too short.
I did a genome comparison between two bacteria with VISTA.
This tools gave me the regions of DNA sequence that are common between two bacteria, but I am most interested in knowing which CDS's are present in one bacteria that is lacking in the second one
By using R, I managed to use the VISTA information to generate a data.frame which includes the region (range) of bases that are exclusive to the FIRST bacteria. These regions must presumibly containing genes (CDS's) that are lacking in the second one.
head(rango_vacio) # Regions (mapped bp) exclusive to the first bacteria
V1 V2
11552 13259
13365 13263
37168 37169
..... .....
By the other way, I have processed a gff file of this same bacteria to extract the CDS sequences. This dataframe contains the start and the end of each of the CDS, along the accession name of the corresponding protein
head(cds_TIGR4) # A list of the cds of this bacteria
startbp endbp accession
197 1158 NP_344444
1717 2853 NP_344445
2864 3112 NP_344446
..... .... .....
IMPORTANT: The data-frames "rango_vacio" and "cds_TIGR4" are both using the same reference as per base is concerned, so I can compare both
Now, the answer to my question should be easy to accomplish, because I only need to find what CDS's are present in each of the rango_vacio ranges using as reference the range of the CDS itself
I can do it by using a very complicated set of for loops, but I am wondering to learn from any of you if this can be accomplished by any other shorter approach
At the very end, I believe I have found myself the method
GenomicRanges cannot be used in my case because one of my data.frame contains the cds range including the strandness. The other one only contains a range
So I used the IRange package instead. I simplify the two data-frames, to contain the start and the end of the range and the cds. One named rango, and the other one cds
library(IRanges)
ir_rango <- IRanges(rango[,1], rango[,2])
ir_cds <- IRanges(cds[,1], cds[,2])
common <- findOverlaps(ir_cds, ir_rango)
common <- as.matrix(common)
unique_cds <- common[,1]
uniques <- which(duplicated(unique_cds))
uniques
uniques contains the row number of the corresponding range shown in ir_cds. Now I only need to extract the name of the cds
First of all, I apologize for the title. I really don't know how to succinctly explain this issue in one sentence.
I have a dataframe where each row represents some aspect of a hospital visit by a patient. A single patient might have thousands of rows for dozens of hospital visits, and each hospital visit could account for several rows.
One column is Medical.Record.Number, which corresponds to Patient IDs, and the other is Patient.ID.Visit, which corresponds to an ID for an individual hospital visit. I am trying to calculate the number of hospital visits each each patient has had.
For example:
Medical.Record.Number Patient.ID.Visit
AAAXXX 1111
AAAXXX 1112
AAAXXX 1113
AAAZZZ 1114
AAAZZZ 1114
AAABBB 1115
AAABBB 1116
would produce the following:
Medical.Record.Number Number.Of.Visits
AAAXXX 3
AAAZZZ 1
AAABBB 2
The solution I am currently using is the following, where "data" is my dataframe:
#this function returns the number of unique hospital visits associated with the
#supplied record number
countVisits <- function(record.number){
visits.by.number <- data$Patient.ID.Visit[which(data$Medical.Record.Number
== record.number)]
return(length(unique(visits.by.number)))
}
recordNumbers <- unique(data$Medical.Record.Number)
visits <- integer()
for (record in recordNumbers){
visits <- c(visits, countVisits(record))
}
visit.counts <- data.frame(recordNumbers, visits)
This works, but it is pretty slow. I am dealing with potentially millions of rows of data, so I'd like something efficient. From what little I know about R, I know there's usually a faster way to do things without using a for-loop.
This essentially looks like a table() operation after you take out duplicates. First, some sample data
#sample data
dd<-read.table(text="Medical.Record.Number Patient.ID.Visit
AAAXXX 1111
AAAXXX 1112
AAAXXX 1113
AAAZZZ 1114
AAAZZZ 1114
AAABBB 1115
AAABBB 1116", header=T)
then you could do
tt <- table(Medical.Record.Number=unique(dd)$Medical.Record.Number)
as.data.frame(tt, responseName="Number.Of.Visits") #to get a data.frame rather than named vector (table)
# Medical.Record.Number Number.Of.Visits
# 1 AAABBB 2
# 2 AAAXXX 3
# 3 AAAZZZ 1
Or you could also think of this as an aggregation problem
aggregate(Patient.ID.Visit~Medical.Record.Number, dd, function(x) length(unique(x)))
# Medical.Record.Number Patient.ID.Visit
# 1 AAABBB 2
# 2 AAAXXX 3
# 3 AAAZZZ 1
There are many ways to do this, #MrFlick provided handful of perfectly valid approaches. Personally I'm fond of the data.table package. Its faster on large data frames and I find the logic to be more intuitive than the base functions. I'd check it out if you are having problems with execution time.
library(data.table)
med.dt <- data.table(med_tbl)
num.visits.dt <- med.dt[ , num_visits = length(unique(Patient.ID.Visit)),
by = Medical.Record.Number]
data.Table should be much faster than data.frame on a large tables.
I am completely new to R. I tried reading the reference and a couple of good introductions, but I am still quite confused.
I am hoping to do the following:
I have produced a .txt file that looks like the following:
area,energy
1.41155882174e-05,1.0914586287e-11
1.46893363946e-05,5.25011714434e-11
1.39244046855e-05,1.57904991488e-10
1.64155121046e-05,9.0815757601e-12
1.85202830392e-05,8.3207522281e-11
1.5256036289e-05,4.24756620609e-10
1.82107587343e-05,0.0
I have the following command to read the file in R:
tbl <- read.csv("foo.txt",header=TRUE).
producing:
> tbl
area energy
1 1.411559e-05 1.091459e-11
2 1.468934e-05 5.250117e-11
3 1.392440e-05 1.579050e-10
4 1.641551e-05 9.081576e-12
5 1.852028e-05 8.320752e-11
6 1.525604e-05 4.247566e-10
7 1.821076e-05 0.000000e+00
Now I want to store each column in two different vectors, respectively area and energy.
I tried:
area <- c(tbl$first)
energy <- c(tbl$second)
but it does not seem to work.
I need to different vectors (which must include only the numerical data of each column) in order to do so:
> prob(energy, given = area), i.e. the conditional probability P(energy|area).
And then plot it. Can you help me please?
As #Ananda Mahto alluded to, the problem is in the way you are referring to columns.
To 'get' a column of a data frame in R, you have several options:
DataFrameName$ColumnName
DataFrameName[,ColumnNumber]
DataFrameName[["ColumnName"]]
So to get area, you would do:
tbl$area #or
tbl[,1] #or
tbl[["area"]]
With the first option generally being preferred (from what I've seen).
Incidentally, for your 'end goal', you don't need to do any of this:
with(tbl, prob(energy, given = area))
does the trick.