Snow Crab Differential Gene Expression

Courtney Skalley
[1] 3294   14
[1] 14  2
   condition        type
1    control single-read
2    control single-read
3    control single-read
4    control single-read
5    control single-read
6    control single-read
7    control single-read
8    control single-read
9     low pH single-read
10    low pH single-read
11    low pH single-read
12    low pH single-read
13    low pH single-read
14    low pH single-read
class: DESeqDataSet 
dim: 3294 14 
metadata(1): version
assays(1): counts
rownames(3294): contig_2632 contig_4568 ... contig_3686 contig_4058
rowData names(0):
colnames(14): X5010_1_S1_L003_R1 X5010_1_S1_L003_R2 ...
  X5010_41_S41_L003_R1 X5010_41_S41_L003_R2
colData names(2): condition type

Snow Crab (Chionoecetes opilio)

Goal: Understand Snow Crab Response to Ocean Acidification

  • Compare snow crab response to ocean acidification
  • Conduct a differential gene expression analysis
  • Using data from Dr. Laura Spencer

Experiment

63 juvenile snow crabs were exposed to different pH treatments for either a long or short duration:

  • control (pH 8.1)
  • pH 7.8
-   short: 8 hours
-   long: 12 weeks
  • pH 7.5
-   short: 8 hours
-   long: 12 weeks

RNA Seq Data

  • mRNA sequencing
  • Each of the 63 samples were run in both lanes
  • 126 paired-end RNA-Seq data sets

Creating a count matrix of sequences

            X5010_1_S1_L003_R1 X5010_1_S1_L003_R2 X5010_2_S2_L003_R1
contig_2632            16.2705          25.966000            6.88181
contig_4568             0.0000           0.000000            0.00000
contig_2580           300.0500         268.228000          212.03100
contig_1896             2.0000           2.000000            0.00000
contig_590           1007.6700         543.944000          506.59700
contig_3193            25.7476           0.397017            7.17347
            X5010_2_S2_L003_R2 X5010_3_S3_L003_R1 X5010_3_S3_L003_R2
contig_2632           13.27460            9.37402            9.83167
contig_4568            0.00000            0.00000            0.00000
contig_2580          187.48600          157.40300          149.38300
contig_1896            0.00000            0.00000            0.00000
contig_590           260.13800          282.95900           99.79770
contig_3193            2.80061           31.80440           37.00930
            X5010_4_S4_L003_R1 X5010_4_S4_L003_R2 X5010_39_S39_L003_R1
contig_2632           11.33060           17.31500              9.82048
contig_4568            0.00000            0.00000              0.00000
contig_2580          656.56300          621.96000           1113.18000
contig_1896            0.00000            0.00000              0.00000
contig_590           314.95100          283.46500            874.03900
contig_3193            1.48772            4.14912              0.00000
            X5010_39_S39_L003_R2 X5010_40_S40_L003_R1 X5010_40_S40_L003_R2
contig_2632             22.48480               6.8945            32.849000
contig_4568              0.00000               0.0000             0.000000
contig_2580           1101.10000             143.6890           188.828000
contig_1896              0.00000               0.0000             0.000000
contig_590             521.94300             904.6130           504.779000
contig_3193              1.99916               0.0000             0.984427
            X5010_41_S41_L003_R1 X5010_41_S41_L003_R2
contig_2632             13.37540             27.27050
contig_4568              0.00000              0.00000
contig_2580            184.25200            176.12200
contig_1896              0.00000              0.00000
contig_590             899.47000            560.60400
contig_3193              6.91905              6.06559

Code for Differential Gene Expression Plot


tmp <- deseq2.res
# The main plot
plot(tmp$baseMean, tmp$log2FoldChange, pch=20, cex=0.45, ylim=c(-3, 3), log="x", col="darkgray",
     main="DEG pH 7.8  (pval <= 0.05)",
     xlab="mean of normalized counts",
     ylab="Log2 Fold Change")
# Getting the significant points and plotting them again so they're a different color
tmp.sig <- deseq2.res[!is.na(deseq2.res$padj) & deseq2.res$padj <= 0.05, ]
points(tmp.sig$baseMean, tmp.sig$log2FoldChange, pch=20, cex=0.45, col="red")
# 2 FC lines
abline(h=c(-1,1), col="blue")

The Result: DGE for Snow Crabs

tmp <- deseq2.res
# The main plot
plot(tmp$baseMean, tmp$log2FoldChange, pch=20, cex=0.45, ylim=c(-3, 3), log="x", col="darkgray",
     main="DEG pH 7.8  (pval <= 0.05)",
     xlab="mean of normalized counts",
     ylab="Log2 Fold Change")
# Getting the significant points and plotting them again so they're a different color
tmp.sig <- deseq2.res[!is.na(deseq2.res$padj) & deseq2.res$padj <= 0.05, ]
points(tmp.sig$baseMean, tmp.sig$log2FoldChange, pch=20, cex=0.45, col="red")
# 2 FC lines
abline(h=c(-1,1), col="blue")

The Result: DGE for Snow Crabs

Next steps

  • Conduct DGE using all 63 samples
  • Update code to combine forward and reverse sequences in DESeq
  • Create and annotate a de novo snow crab transcriptome