将基因位置映射到染色体坐标

map gene positions to chromosome coordinates

首先post在这里,所以我希望我能最好地解释一下自己。

我需要通过查找两个数据帧之一中给定的特定染色体位置是否出现在另一个数据帧提供的范围内来交叉引用两个数据帧,因此我想有一个新列该范围内存在的基因。

"genes"是坐标(start/end)被认为是范围

的dataframe
head(genes)
# A tibble: 6 x 9
  chr   source         type      start       end strand gene_id         symbol        gene_biotype  
  <chr> <chr>          <chr>     <int>     <int> <chr>  <chr>           <chr>         <chr>         
1 2     pseudogene     gene  143300987 143301544 +      ENSG00000228134 AC092578.1    pseudogene    
2 2     pseudogene     gene  143611664 143613567 +      ENSG00000229781 AC013444.1    pseudogene    
3 2     protein_coding gene  143635067 143799890 +      ENSG00000115919 KYNU          protein_coding
4 2     pseudogene     gene  143704869 143705655 -      ENSG00000270390 RP11-470B22.1 pseudogene    
5 2     miRNA          gene  143763269 143763360 -      ENSG00000221169 AC013444.2    miRNA         
6 2     protein_coding gene  143848931 144525921 +      ENSG00000075884 ARHGAP15      protein_coding

另一个数据框(x)是:

  chr_a   point A
1     2 143301002 
2     2 143625061
3     2 143700941
4     2 143811317
5     2 144127323
6     2 144224689

我基本上必须找出 "point A" 是否落在 "start"/ "end" 范围之间(基因)以及相关的基因符号。

我尝试了以下方法:

x$geneA <- ifelse(sapply(x$`point A`, function(g)
  any(genes$start >= g & genes$end <=g)), genes$symbol, NA)

但我得到的结果与基因组坐标不一致

希望有人能帮助我!谢谢!

这个有用吗?

我假设每个点只匹配一个基因符号。

x$geneA <- sapply(x$`point A`,
                  function(g) filter(genes, g >= start & g <= end)$symbol[1])

结果:

x

# A tibble: 6 x 3
  chr_a `point A` geneA     
  <int>     <int> <chr>     
1     2 143301002 AC092578.1
2     2 143625061 NA        
3     2 143700941 KYNU      
4     2 143811317 NA        
5     2 144127323 ARHGAP15  
6     2 144224689 ARHGAP15 

基于 for 循环的解决方案。 (当然,这比使用 apply 慢得多。)

#A mock-up of your data
symbol <- c("AC092578.1", "AC013444.1", "KYNU", "RP11-470B22.1", "AC013444.2", "ARHGAP15", "Newadditionalsymbol")
start <- c(143300987, 143611664, 143635067, 143704869, 143763269, 143848931, 143300987)
end <- c(143301544, 143613567, 143799890, 143705655, 143763360, 144525921, 143301044)

genes <- data.frame(start, end, symbol, stringsAsFactors = F)

point_A <- start[1:6]+1
chr_1 <- rep_len(2, length.out = length(point_A))

x <- data.frame(chr_1, point_A, stringsAsFactors = F)

x$symbol <- NA #Create a new column to store the symbols, populate it with NA

x

#      chr_1   point_A symbol
# 1     2 143300988     NA
# 2     2 143611665     NA
# 3     2 143635068     NA
# 4     2 143704870     NA
# 5     2 143763270     NA
# 6     2 143848932     NA

#Solution using a for loop
for(i in 1:nrow(x)){ #Iterate through every row of x

  for(j in 1:nrow(genes)){ #Iterate through every row of genes

    if(x$point_A[i] >= genes$start[j] & x$point_A[i] < genes$end[j]){ #If the ith point_A falls within the jth start & end

      if(is.na(x$symbol[i])){ #If there is no symbol assigned to the ith row of x

        x$symbol[i] <- genes$symbol[j] #Assign the symbol from the jth row

      } else{ #If there is a symbol assigned to the ith row of x already, and it matches (now, another) jth row of genes
        x$symbol[i] <- paste(x$symbol[i], genes$symbol[j]) #Concatenate the new symbol from the jth row of genes to the ith row of x
      }

    }

  }
}

x

#   chr_1   point_A                         symbol
# 1     2 143300988 AC092578.1 Newadditionalsymbol
# 2     2 143611665                     AC013444.1
# 3     2 143635068                           KYNU
# 4     2 143704870             KYNU RP11-470B22.1
# 5     2 143763270                KYNU AC013444.2
# 6     2 143848932                       ARHGAP15

欢迎使用 Whosebug!将来,请 post 一个最小的、可行的示例 (MWE)。

genes <- tribble(~chr, ~source, ~type, ~start, ~end, ~strand, ~gene_id, ~symbol, ~gene_biotype,
                  2, "pseudogene", "gene", 143300987, 143301544, "+", "ENSG00000228134", "AC092578.1", "pseudogene",
                  2, "pseudogene", "gene", 143611664, 143613567, "+", "ENSG00000229781", "AC013444.1", "pseudogene",
                  2, "protein_coding", "gene", 143635067, 143799890, "+", "ENSG00000115919", "KYNU", "protein_coding",
                  2, "pseudogene", "gene", 143704869, 143705655, "-", "ENSG00000270390", "RP11-470B22.1", "pseudogene",
                  2, "miRNA", "gene", 143763269, 143763360, "-", "ENSG00000221169", "AC013444.2", "miRNA",
                  2, "protein_coding", "gene", 143848931, 144525921, "+", "ENSG00000075884", "ARHGAP15", "protein_coding")

x <- tribble(~chr_a, ~`point A`,
              2, 143301002,
              2, 143625061,
              2, 143700941,
              2, 143811317,
              2, 144127323,
              2, 144224689,
)

我给你一个tidyverse方法:

x %>% 
    nest_join(genes, by = c("chr_a" = "chr")) %>% 
    group_by(`point A`) %>% 
    mutate(genes = map(genes, ~filter(., `point A` >= start & `point A` <= end))) %>% 
    unnest(genes, keep_empty = TRUE)

用于合并 table,其中不匹配的行是 NA。或者简单地找到匹配的那些而不使用嵌套的 tibbles

x %>% 
    left_join(genes, by = c("chr_a" = "chr")) %>% 
    filter(`point A` >= start & `point A` <= end)

您可以尝试下面的基本 R 代码

df2out <- within(df2,symbol <- sapply(A, function(x) df1$symbol[which(x>=df1$start & x<=df1$end)]))

这样

> df2out
  chr_a point         A     symbol
1     1     2 143301002 AC092578.1
2     2     2 143625061           
3     3     2 143700941       KYNU
4     4     2 143811317           
5     5     2 144127323   ARHGAP15
6     6     2 144224689   ARHGAP15

数据

df1 <- structure(list(chr = c(2L, 2L, 2L, 2L, 2L, 2L), source = c("pseudogene", 
"pseudogene", "protein_coding", "pseudogene", "miRNA", "protein_coding"
), type = c("gene", "gene", "gene", "gene", "gene", "gene"), 
    start = c(143300987L, 143611664L, 143635067L, 143704869L, 
    143763269L, 143848931L), end = c(143301544L, 143613567L, 
    143799890L, 143705655L, 143763360L, 144525921L), strand = c("+", 
    "+", "+", "-", "-", "+"), gene_id = c("ENSG00000228134", 
    "ENSG00000229781", "ENSG00000115919", "ENSG00000270390", 
    "ENSG00000221169", "ENSG00000075884"), symbol = c("AC092578.1", 
    "AC013444.1", "KYNU", "RP11-470B22.1", "AC013444.2", "ARHGAP15"
    ), gene_biotype = c("pseudogene", "pseudogene", "protein_coding", 
    "pseudogene", "miRNA", "protein_coding")), class = "data.frame", row.names = c(NA, 
-6L))

df2 <- structure(list(chr_a = 1:6, point = c(2L, 2L, 2L, 2L, 2L, 2L), 
    A = c(143301002L, 143625061L, 143700941L, 143811317L, 144127323L, 
    144224689L)), class = "data.frame", row.names = c(NA, -6L
))

很可能永远不会看到这个答案=p

有这方面的软件包。请注意,您的代码不适用于额外的染色体或链。

使用@koenniem 的数据,

library(GenomicRanges)

gr1 = makeGRangesFromDataFrame(genes,keep.extra.columns=TRUE)

x = data.frame(x,check.names=FALSE)
gr2 = GRanges(seqnames=x$chr_a,IRanges(start=x[,"point A"],width=1))

x$gene = NA
ovlp = findOverlaps(gr2,gr1)
x$gene[queryHits(ovlp)] = gr1$symbol[subjectHits(ovlp)]

  chr_a   point A       gene
1     2 143301002 AC092578.1
2     2 143625061       <NA>
3     2 143700941       KYNU
4     2 143811317       <NA>
5     2 144127323   ARHGAP15
6     2 144224689   ARHGAP15