qiime2R

Qiime

My sequencing was done by Ion Torrent which made Qiime a bit difficult to use because of lacking documentation. I followed, mostly, this post by Carli Jones: https://forum.qiime2.org/t/possible-analysis-pipeline-for-ion-torrent-16s-metagenomics-kit-data-in-qiime2/13476.

Pipeline

  1. Import fastq using “manifest” file format
  2. Perform DADA2
  3. Explore feature counts
  4. Create phylogenetic tree using SEPP (fragment insertion)
  5. Alpha rarefaction
  6. Core metrics analysis

Qiime outputs, R plots

For this project data visualization is the most important part because it’s pilot data for a new project. qiime2R has really good documentation; for details see https://github.com/jbisanz/qiime2R.

First I uploaded the Qiime2 output files needed to make my plot which was very straightforward following the documentation by Dr. Jordan Bisanz.

metadata<-read_tsv("warfgi_qiime_meta.tsv")
colnames(metadata)[colnames(metadata) == "sampleid"] = "SampleID"
uwunifrac<-read_qza("unweighted_unifrac_pcoa_results.qza")
shannon<-read_qza("shannon_vector.qza")$data %>% rownames_to_column("SampleID")

Plotting

Again, using code from the qiime2r documentation, I plotted the first two PCs with sizing by Alpha Diversity.

uwunifrac$data$Vectors %>%
  select(SampleID, PC1, PC2) %>%
  left_join(metadata) %>%
  left_join(shannon) %>%
  ggplot(aes(x=PC1, y=PC2, color=`samplegroup`, size=shannon)) +
  geom_point(alpha=0.8) + #alpha controls transparency and helps when points are overlapping
  theme_q2r() +
  scale_size_continuous(name="Shannon Diversity") +
  scale_color_discrete(name="Patient") + 
  scale_color_viridis(discrete = T, name = "patient")

Tada!

Heidi E. Steiner
Heidi E. Steiner
Senior Clinical Data Scientist

I love coding in R, biostatistics, and reproducible clinical research.