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Introduction

The data in this vignette is shipped with the cellatlas repository. The count matrix and metadata are provided in the cellatlas/examples folder as an AnnData object. We will begin by loading the object and converting it to a SingleCellExperiment object.

if (!file.exists("clicktags.rds"))
    download.file("https://github.com/pachterlab/voyager/raw/documentation-devel/vignettes/clicktags.rds", destfile = "clicktags.rds")
sce <- readRDS("clicktags.rds")
sce <- addPerCellQCMetrics(sce)
names(colData(sce))
#> [1] "sum"      "detected" "total"
plotColData(sce, "sum") +
    plotColData(sce, "detected") 

plotColData(sce, x = "sum", y = "detected", bins = 100) +
    scale_fill_distiller(palette = "Blues", direction = 1)
#> Scale for fill is already present.
#> Adding another scale for fill, which will replace the existing scale.

bcrank <- barcodeRanks(counts(sce))

knee <- metadata(bcrank)$knee
inflection <- metadata(bcrank)$inflection

plot(bcrank$rank, bcrank$total, log="xy",
      xlab="Rank", ylab="Total ClickTags count", cex.lab=1.2)
#> Warning in xy.coords(x, y, xlabel, ylabel, log): 1 y value <= 0 omitted from
#> logarithmic plot

abline(h=inflection, col="darkgreen", lty=2)
abline(h=knee, col="dodgerblue", lty=2)

sce <- sce[, colSums(counts(sce)) > inflection]

sce
#> class: SingleCellExperiment 
#> dim: 20 3368 
#> metadata(0):
#> assays(1): counts
#> rownames(20): ClickTag1 ClickTag2 ... ClickTag19 ClickTag20
#> rowData names(1): feature_name
#> colnames(3368): AAACCTGCAAACTGCT AAACCTGGTAGCTTGT ... TTTGTCAGTCACCCAG
#>   TTTGTCATCTCTTATG
#> colData names(3): sum detected total
#> reducedDimNames(0):
#> mainExpName: NULL
#> altExpNames(0):
sessionInfo()
#> R version 4.4.0 (2024-04-24)
#> Platform: x86_64-apple-darwin20
#> Running under: macOS Ventura 13.6.6
#> 
#> Matrix products: default
#> BLAS:   /Library/Frameworks/R.framework/Versions/4.4-x86_64/Resources/lib/libRblas.0.dylib 
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.4-x86_64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.0
#> 
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#> 
#> time zone: UTC
#> tzcode source: internal
#> 
#> attached base packages:
#> [1] stats4    stats     graphics  grDevices utils     datasets  methods  
#> [8] base     
#> 
#> other attached packages:
#>  [1] Voyager_1.6.0                  scater_1.32.0                 
#>  [3] ggplot2_3.5.1                  scuttle_1.14.0                
#>  [5] SpatialFeatureExperiment_1.6.1 SpatialExperiment_1.14.0      
#>  [7] Matrix_1.7-0                   DropletUtils_1.24.0           
#>  [9] SingleCellExperiment_1.26.0    SummarizedExperiment_1.34.0   
#> [11] Biobase_2.64.0                 GenomicRanges_1.56.0          
#> [13] GenomeInfoDb_1.40.0            IRanges_2.38.0                
#> [15] S4Vectors_0.42.0               BiocGenerics_0.50.0           
#> [17] MatrixGenerics_1.16.0          matrixStats_1.3.0             
#> [19] stringr_1.5.1                 
#> 
#> loaded via a namespace (and not attached):
#>   [1] RColorBrewer_1.1-3        jsonlite_1.8.8           
#>   [3] wk_0.9.1                  magrittr_2.0.3           
#>   [5] ggbeeswarm_0.7.2          magick_2.8.3             
#>   [7] farver_2.1.2              rmarkdown_2.27           
#>   [9] fs_1.6.4                  zlibbioc_1.50.0          
#>  [11] ragg_1.3.2                vctrs_0.6.5              
#>  [13] spdep_1.3-3               memoise_2.0.1            
#>  [15] DelayedMatrixStats_1.26.0 RCurl_1.98-1.14          
#>  [17] terra_1.7-71              htmltools_0.5.8.1        
#>  [19] S4Arrays_1.4.0            BiocNeighbors_1.22.0     
#>  [21] Rhdf5lib_1.26.0           s2_1.1.6                 
#>  [23] SparseArray_1.4.3         rhdf5_2.48.0             
#>  [25] sass_0.4.9                spData_2.3.0             
#>  [27] KernSmooth_2.23-24        bslib_0.7.0              
#>  [29] htmlwidgets_1.6.4         desc_1.4.3               
#>  [31] cachem_1.1.0              igraph_2.0.3             
#>  [33] lifecycle_1.0.4           pkgconfig_2.0.3          
#>  [35] rsvd_1.0.5                R6_2.5.1                 
#>  [37] fastmap_1.2.0             GenomeInfoDbData_1.2.12  
#>  [39] digest_0.6.35             ggnewscale_0.4.10        
#>  [41] colorspace_2.1-0          patchwork_1.2.0          
#>  [43] RSpectra_0.16-1           dqrng_0.4.0              
#>  [45] irlba_2.3.5.1             textshaping_0.3.7        
#>  [47] beachmat_2.20.0           labeling_0.4.3           
#>  [49] fansi_1.0.6               httr_1.4.7               
#>  [51] abind_1.4-5               compiler_4.4.0           
#>  [53] proxy_0.4-27              withr_3.0.0              
#>  [55] tiff_0.1-12               BiocParallel_1.38.0      
#>  [57] viridis_0.6.5             DBI_1.2.2                
#>  [59] highr_0.10                HDF5Array_1.32.0         
#>  [61] R.utils_2.12.3            DelayedArray_0.30.1      
#>  [63] bluster_1.14.0            rjson_0.2.21             
#>  [65] classInt_0.4-10           tools_4.4.0              
#>  [67] units_0.8-5               vipor_0.4.7              
#>  [69] beeswarm_0.4.0            R.oo_1.26.0              
#>  [71] glue_1.7.0                EBImage_4.46.0           
#>  [73] rhdf5filters_1.16.0       grid_4.4.0               
#>  [75] sf_1.0-16                 cluster_2.1.6            
#>  [77] memuse_4.2-3              generics_0.1.3           
#>  [79] gtable_0.3.5              R.methodsS3_1.8.2        
#>  [81] class_7.3-22              data.table_1.15.4        
#>  [83] BiocSingular_1.20.0       ScaledMatrix_1.12.0      
#>  [85] sp_2.1-4                  utf8_1.2.4               
#>  [87] XVector_0.44.0            ggrepel_0.9.5            
#>  [89] pillar_1.9.0              limma_3.60.0             
#>  [91] dplyr_1.1.4               lattice_0.22-6           
#>  [93] deldir_2.0-4              tidyselect_1.2.1         
#>  [95] locfit_1.5-9.9            sfheaders_0.4.4          
#>  [97] knitr_1.46                gridExtra_2.3            
#>  [99] edgeR_4.2.0               xfun_0.44                
#> [101] statmod_1.5.0             stringi_1.8.4            
#> [103] UCSC.utils_1.0.0          fftwtools_0.9-11         
#> [105] yaml_2.3.8                boot_1.3-30              
#> [107] evaluate_0.23             codetools_0.2-20         
#> [109] tibble_3.2.1              cli_3.6.2                
#> [111] systemfonts_1.1.0         munsell_0.5.1            
#> [113] jquerylib_0.1.4           Rcpp_1.0.12              
#> [115] zeallot_0.1.0             png_0.1-8                
#> [117] parallel_4.4.0            pkgdown_2.0.9            
#> [119] jpeg_0.1-10               sparseMatrixStats_1.16.0 
#> [121] bitops_1.0-7              viridisLite_0.4.2        
#> [123] scales_1.3.0              e1071_1.7-14             
#> [125] purrr_1.0.2               crayon_1.5.2             
#> [127] scico_1.5.0               rlang_1.1.3              
#> [129] cowplot_1.1.3