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跟着Molecular Plant学作图：R语言circlize包画圈图展示基因组的一些特征

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发布于 2023-01-06 12:15:46

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代码可运行

文章被收录于专栏：小明的数据分析笔记本小明的数据分析笔记本

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代码可运行

论文

A telomere-to-telomere gap-free reference genome of watermelon and its mutation library provide important resources for gene discovery and breeding

https://www.cell.com/molecular-plant/fulltext/S1674-2052(22)00192-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1674205222001927%3Fshowall%3Dtrue

今天的推文我们重复一下论文中的Figure1a

image.png

论文中没有提供数据和代码，数据自己算，代码自己写

之前分享过的关于圈图的推文

跟着Nature Communications学画图：R语言circlize包画弦图展示基因密度

根据vcf文件计算SNP密度并用circlize可视化结果

R包circlize绘制基因组重测序变异圈图示例

计算gc含量和基因密度

利用基因组fasta文件统计染色体长度和GC含量，自己写python脚本（当然有很多工具可以统计）利用gtf文件统计基因密度

读取fasta用到了biopython

class WaterMelon:
    def __init__(self,gtf,fasta):
        self.gtf = gtf
        self.fasta = fasta
        
    def chromoLen(self):
        chrLen = {}
        for rec in SeqIO.parse(self.fasta,'fasta'):
            chrLen[rec.id] = len(rec.seq)
            
        return chrLen
    
    def gcContent(self,gc_window):
        self.gc_window = gc_window
        
        gc_content = {'chr_id':[],
                     'bin_start':[],
                     'gc':[]}
        chr_len = self.chromoLen()
        
        #print(chr_len)
        for rec in SeqIO.parse(self.fasta,'fasta'):
            for i in range(0,chr_len[rec.id],self.gc_window):
                #print(rec.id)
                gc_content['chr_id'].append(rec.id)
                gc_content['bin_start'].append(i)
                gc_content['gc'].append(round(GC(rec.seq[i:i+self.gc_window]),2))
        return pd.DataFrame(gc_content)
    
    def geneDensity(self,gene_window):
        self.gene_window = gene_window
        final_df = []
        df = pd.read_table(self.gtf,header=None,comment="#",sep="\t",
                           usecols=[0,2,3,4],
                           names="Chromosome Feature Start End".split())
        #df.columns = "Chromosome Source Feature Start End Score Strand Frame Attribute".split()
        df = df[df.Feature=="gene"]
        chrLen = self.chromoLen()
        for chr_id in chrLen.keys():
            print(chr_id)
            df1 = df[df.Chromosome==chr_id]
            gene_start = [int(a) for a in df1.Start]
            gene_start.insert(0,0)
            gene_start.append(round(chrLen[chr_id]/self.gene_window)*self.gene_window+self.gene_window)
            #print(gene_start)
            bin_start = [int(a.left) for a in pd.cut(gene_start,bins=round(chrLen[chr_id]/self.gene_window)+1).value_counts().index]
            bin_start[0] = 0
            gene_count = list(pd.cut(gene_start,bins=round(chrLen[chr_id]/self.gene_window)+1).value_counts().values)
            #print(len(bin_start))
            #print(len(gene_count))
            #print("OK")
            final_df.append(pd.DataFrame({'chr_id':chr_id,'bin_start':bin_start,'gene_count':gene_count}))
            
        return pd.concat(final_df)

这里是用python算的

TE的密度暂时不知道怎么算，snp和indel的密度可以使用vcftools软件，但是没有找到输入文件

首先是读取数据

df<-read.csv("D:/Jupyter/bioinformatics_python/MPwatermelon.csv")
gc<-read.csv("D:/Jupyter/bioinformatics_python/gc.csv")
genedensity<-read.csv("D:/Jupyter/bioinformatics_python/genedensity.csv")

max(df$chr_len)
head(gc)
range(gc$gc)
head(genedensity)
range(genedensity$gene_count)

genedensity %>% 
  mutate(group=case_when(
    gene_count < 35 ~ "#1efc05",
    gene_count > 50 ~ "red",
    TRUE ~ "black"
  )) -> genedensity

染色体长度数据

image.png

gc含量数据

image.png

基因密度数据

image.png

作图代码

library(circlize)
brk <- seq(0,40,by=2)*10^6
brk.label<-c()
for (i in brk){
  ifelse(i%%10^7==0,brk.label<-append(brk.label,
                                      paste0(i/10^7,"0M")),
         brk.label<-append(brk.label,""))
}
brk.label[1]<-"0M"
brk.label

#circos.par(points.overflow.warning = FALSE)
pdf(file = "mp.pdf",
    width = 15,height = 15)
circos.par(start.degree =86,clock.wise = T)
circos.initialize(factors = df$chr_id, 
                  xlim = matrix(c(rep(0,11),df$chr_len),ncol=2))
circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 10),
                       track.height = 0.1,
                       bg.border = NA, 
                       #ylim=CELL_META$ylim,
                       panel.fun = function(x, y) {
                         circos.text(mean(CELL_META$xlim), 12, 
                                     get.cell.meta.data("sector.index"))
                       })

circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 100),
                       track.height = 0.1,
                       bg.col = '#EEEEEE6E', 
                       bg.border = NA)


for (chromosome in df$chr_id){
  circos.axis(sector.index = chromosome,
              h = 110,
              major.at = brk,
              minor.ticks = 0,
              labels = brk.label,
              labels.facing="clockwise",
              labels.cex = 0.6)
}

circos.trackLines(gc$chr_id,gc$bin_start,gc$gc,
                  area = TRUE,
                  col = "red",
                  border="transparent")

circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 10),
                       track.height = 0.1,
                       bg.col = '#EEEEEE6E', 
                       bg.border = NA)

for (chromosome in df$chr_id){
  circos.segments(sector.index = chromosome,
                  x0=genedensity[genedensity$chr_id==chromosome,]$bin_start,
                  x1=genedensity[genedensity$chr_id==chromosome,]$bin_start,
                  y0=0,y1=10,col=genedensity[genedensity$chr_id==chromosome,]$group)
}


circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 10),
                       track.height = 0.1,
                       bg.col = '#EEEEEE6E', 
                       bg.border = NA)

for (chromosome in df$chr_id){
  circos.segments(sector.index = chromosome,
                  x0=genedensity[genedensity$chr_id==chromosome,]$bin_start,
                  x1=genedensity[genedensity$chr_id==chromosome,]$bin_start,
                  y0=0,y1=10,col=genedensity[genedensity$chr_id==chromosome,]$group)
}

circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 100),
                       track.height = 0.1,
                       bg.col = '#EEEEEE6E', 
                       bg.border = NA)

for (chromosome in df$chr_id){
  circos.barplot(sector.index = chromosome,
                 value = genedensity[genedensity$chr_id==chromosome,]$gene_count,
                 pos = genedensity[genedensity$chr_id==chromosome,]$bin_start,
                 col = "red",
                 bar_width = 500000,
                 border="transparent")
}

circos.trackPlotRegion(df$chr_id, 
                       ylim = c(0, 100),
                       track.height = 0.1,
                       bg.col = '#EEEEEE6E', 
                       bg.border = NA)

for (chromosome in df$chr_id){
  circos.barplot(sector.index = chromosome,
                 value = genedensity[genedensity$chr_id==chromosome,]$gene_count,
                 pos = genedensity[genedensity$chr_id==chromosome,]$bin_start,
                 col = "blue",
                 bar_width = 500000,
                 border="transparent")
}


circos.clear()
dev.off()