Comparing multiple datasets- Merge

```{r}
# Load libraries
library(SingleCellExperiment)
library(Seurat)
library(tidyverse)
library(Matrix)
library(scales)
library(cowplot)
library(RCurl)
```


```{r}

# Specify the name of the directory you want to create
directory_name <- "Sample_A_Sample_B"

# Specify the location where the directory should be created
# Full path example:
full_path <- "../(Enter directory for output)/"


# Create the directory using the full path
dir.create(file.path(full_path, directory_name))


output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"
```


```{r}
Sample_A <- Read10X(data.dir = "../(Enter pathway to sample A)/Sample_A/")
Sample_A_filter <- CreateSeuratObject(counts = Sample_A, min.features = 100)


Sample_B <- Read10X(data.dir = "../(Enter pathway to sample B)/Sample_B/")
Sample_B_filter <- CreateSeuratObject(counts = Sample_B, min.features = 100)

rm(Sample_A, Sample_B)



merged_seurat <- merge(Sample_A_filter, y = c(Sample_B_filter), add.cell.ids = c("Sample_A","Sample_B"),project = "merged")
head(merged_seurat@meta.data)
tail(merged_seurat@meta.data)
# Add number of genes per UMI for each cell to metadata
merged_seurat$log10GenesPerUMI <- log10(merged_seurat$nFeature_RNA) / log10(merged_seurat$nCount_RNA)
# Compute percent mito ratio
merged_seurat$mitoRatio <- PercentageFeatureSet(object = merged_seurat, pattern = "^mt-")
merged_seurat$mitoRatio <- merged_seurat@meta.data$mitoRatio / 100
# Create metadata dataframe
metadata <- merged_seurat@meta.data
# Add cell IDs to metadata
metadata$cells <- rownames(metadata)
# Create sample column
metadata$sample <- NA

metadata$sample[which(str_detect(metadata$cells, "^Sample_A"))] <- "Sample_A"
metadata$sample[which(str_detect(metadata$cells, "^Sample_B"))] <- "Sample_B"


# Rename columns
metadata <- metadata %>%
dplyr::rename(seq_folder = orig.ident,
nUMI = nCount_RNA,
nGene = nFeature_RNA)
# Add metadata back to Seurat object
merged_seurat@meta.data <- metadata
# Create .RData object to load at any time
# Visualize the number of cell counts per sample
metadata %>%
ggplot(aes(x=sample, fill=sample)) +
geom_bar() +
theme_classic() +
theme(axis.text.x = element_text(angle = 45, vjust = 1, hjust=1)) +
theme(plot.title = element_text(hjust=0.5, face="bold")) +
ggtitle("NCells")
# Visualize the number UMIs/transcripts per cell
metadata %>%
ggplot(aes(color=sample, x=nUMI, fill= sample)) +
geom_density(alpha = 0.2) +
scale_x_log10() +
theme_classic() +
ylab("Cell density") +
geom_vline(xintercept = 2000)
# Visualize the distribution of genes detected per cell via histogram
metadata %>%
ggplot(aes(color=sample, x=nGene, fill= sample)) +
geom_density(alpha = 0.2) +
theme_classic() +
scale_x_log10() +
geom_vline(xintercept = 300)
# Visualize the distribution of genes detected per cell via boxplot
metadata %>%
ggplot(aes(x=sample, y=log10(nGene), fill=sample)) +
geom_boxplot() +
theme_classic() +
theme(axis.text.x = element_text(angle = 45, vjust = 1, hjust=1)) +
theme(plot.title = element_text(hjust=0.5, face="bold")) +
ggtitle("NCells vs NGenes")
# Visualize the correlation between genes detected and number of UMIs and determine whether strong presence of cells with low numbers of genes/UMIs
metadata %>%
ggplot(aes(x=nUMI, y=nGene, color=mitoRatio)) +
geom_point() +
scale_colour_gradient(low = "gray90", high = "black") +
stat_smooth(method=lm) +
scale_x_log10() +
scale_y_log10() +
theme_classic() +
geom_vline(xintercept = 1200) +
geom_hline(yintercept = 500) +
facet_wrap(~sample)
# Visualize the distribution of mitochondrial gene expression detected per cell
metadata %>%
ggplot(aes(color=sample, x=mitoRatio, fill=sample)) +
geom_density(alpha = 0.2) +
scale_x_log10() +
theme_classic() +
geom_vline(xintercept = 0.2)
# Visualize the overall complexity of the gene expression by visualizing the genes detected per UMI
metadata %>%
ggplot(aes(x=log10GenesPerUMI, color = sample, fill=sample)) +
geom_density(alpha = 0.2) +
theme_classic() +
geom_vline(xintercept = 0.85)

# Filter out low quality cells using selected thresholds - these will change with experiment
filtered_seurat <- subset(x = merged_seurat,
subset= (nUMI >= 500) &
(nGene >= 300) &
(log10GenesPerUMI > 0.85) &
(mitoRatio < 0.20))
# Extract counts
counts <- GetAssayData(object = filtered_seurat, slot = "counts")
# Output a logical matrix specifying for each gene on whether or not there are more than zero counts per cell
nonzero <- counts > 0
# Sums all TRUE values and returns TRUE if more than 10 TRUE values per gene
keep_genes <- Matrix::rowSums(nonzero) >= 10
# Only keeping those genes expressed in more than 10 cells
filtered_counts <- counts[keep_genes, ]
# Reassign to filtered Seurat object
filtered_seurat <- CreateSeuratObject(filtered_counts, meta.data = filtered_seurat@meta.data)
```


```{r}
#without integration
Seurat_Merged <- filtered_seurat
Seurat_Merged <- NormalizeData(Seurat_Merged, verbose = FALSE)
Seurat_Merged <- FindVariableFeatures(object = Seurat_Merged, selection.method = 'vst', nfeatures = 3000)

all.genes <- rownames(Seurat_Merged)
Seurat_Merged <- ScaleData(Seurat_Merged, features = all.genes)
Seurat_Merged <- RunPCA(Seurat_Merged, features = VariableFeatures(object = Seurat_Merged))
ElbowPlot(Seurat_Merged, ndims = 100)

DimPlot(Seurat_Merged, reduction = 'pca')
Seurat_Merged <- FindNeighbors(object=Seurat_Merged, dims = 1:45, k.param =20 ,)
Seurat_Merged <- FindClusters(Seurat_Merged, resolution = 0.25)
Seurat_Merged <- RunUMAP(Seurat_Merged, dims = 1:45, seed.use = 1)
DimPlot(Seurat_Merged, reduction = "umap", label = T)
DimPlot(Seurat_Merged, reduction = 'umap', label = T, split.by = "sample", ncol = 3)

```

```{r}

library(gridExtra)



# Set the desired order of groups
group_order <- c('Sample_B', 'Sample_A')

# Change the order of the factor levels
Seurat_Merged$sample <- factor(Seurat_Merged$sample, levels = group_order)

# Generate the first plot
plot1 <- DimPlot(Seurat_Merged, reduction = "umap", label = TRUE)

# Generate the second plot
plot2 <- DimPlot(Seurat_Merged, reduction = "umap", label = TRUE, split.by = "sample", ncol = 3)

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

ggsave(filename = file.path(output_dir, "UMAP.png"), plot = ggplotGrob(plot1), dpi = 300)
ggsave(filename = file.path(output_dir, "UMAP_split.png"), plot = ggplotGrob(plot2), dpi = 300)
```

```{r}

Seurat_Merged_cells <- FetchData(Seurat_Merged, 
                     vars = c("ident", "sample")) %>%
    dplyr::count(ident, sample) %>%
    tidyr::spread(ident, n)

# View table
View(Seurat_Merged_cells)

Seurat_Merged_markers <- FindAllMarkers(Seurat_Merged, only.pos = F, min.pct = 0.25, logfc.threshold = 0.25, base = exp(1))

write.csv(Seurat_Merged_markers, file = file.path(output_dir, "Seurat_Merged_markers.csv"))

top5 <- Seurat_Merged_markers %>% group_by(cluster) %>% top_n(n = 10, wt = avg_logFC)
DefaultAssay(Seurat_Merged) <- 'RNA'
Seurat_Merged <- ScaleData(Seurat_Merged, features = all.genes)


# Generate the heatmap
heatmap <- DoHeatmap(Seurat_Merged, features = top5$gene) + NoLegend()

heatmap

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

# Specify the file path and name for saving the heatmap
file_path <- file.path(output_dir, "heatmap.tiff")

# Save the heatmap as a TIFF image
tiff(filename = file_path, width = 8, height = 6, units = "in", res = 300)
print(heatmap)
dev.off()
```




```{r}

#Enter your list of genes here
genes.list <- c("GeneA", "GeneB")

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"


vlnplots_dir <- file.path(output_dir, "Vlnplots")
dir.create(vlnplots_dir, recursive = TRUE)

plot.list <- list()
datasample <- vector("character", length(genes.list))

for (i in 1:length(genes.list)) {
  plot.list[[i]] <- VlnPlot(object = Seurat_Merged, features = genes.list[[i]], split.by = "sample")
  
  datasample[[i]] <- paste(genes.list[[i]], ".png", sep = "")
  
  file_path <- file.path(vlnplots_dir, datasample[[i]])
  
  ggsave(filename = file_path, plot = plot.list[[i]])
}

#Enter your list of genes here
genes.list <- c("GeneA", "GeneB")

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

vlnplots_dir <- file.path(output_dir, "Featureplots")
dir.create(vlnplots_dir, recursive = TRUE)

plot.list <- list()
datasample <- vector("character", length(genes.list))


for (i in 1:length(genes.list)) {
  plot.list[[i]] <- FeaturePlot(object = Seurat_Merged, features = genes.list[[i]], split.by = "sample", label = T)
  
  datasample[[i]] <- paste(genes.list[[i]], ".png", sep = "")
  
  file_path <- file.path(vlnplots_dir, datasample[[i]])
  
  ggsave(filename = file_path, plot = plot.list[[i]])
}
```

```{r}
genes.list <-  top5$gene

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"


vlnplots_dir <- file.path(output_dir, "Vlnplots_top10")
dir.create(vlnplots_dir, recursive = TRUE)

plot.list <- list()
datasample <- vector("character", length(genes.list))

for (i in 1:length(genes.list)) {
  plot.list[[i]] <- VlnPlot(object = Seurat_Merged, features = genes.list[[i]], split.by = "sample")
  
  datasample[[i]] <- paste(genes.list[[i]], ".png", sep = "")
  
  file_path <- file.path(vlnplots_dir, datasample[[i]])
  
  ggsave(filename = file_path, plot = plot.list[[i]])
}

genes.list <-  top5$gene


output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

vlnplots_dir <- file.path(output_dir, "Featureplots_top10")
dir.create(vlnplots_dir, recursive = TRUE)

plot.list <- list()
datasample <- vector("character", length(genes.list))

for (i in 1:length(genes.list)) {
  plot.list[[i]] <- FeaturePlot(object = Seurat_Merged, features = genes.list[[i]], split.by = "sample", label = T)
  
  datasample[[i]] <- paste(genes.list[[i]], ".png", sep = "")
  
  file_path <- file.path(vlnplots_dir, datasample[[i]])
  
  ggsave(filename = file_path, plot = plot.list[[i]])
}
```



```{r}

# Reshape the data frame from wide to long format
df_long <- tidyr::gather(Seurat_Merged_cells, key = "Cluster", value = "ClusterNumber", -sample)

# Define the custom breaks
custom_breaks <- c(0,1000, 2000, 3000, 4000, 5000, 6000, 7000)

# Create the plot
plot <- ggplot(df_long, aes(x = sample, y = ClusterNumber, fill = Cluster)) +
  geom_bar(stat = "identity", position = "dodge") +
  labs(x = "sample", y = "Cell Number", fill = "Cluster") +
  theme_minimal() +
  scale_y_continuous(breaks = custom_breaks)

output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"


# Specify the file path and name for saving the plot
file_path <- file.path(output_dir, "raw_cluster_numbers.png")

# Save the plot as a PNG file
ggsave(filename = file_path, plot = plot, dpi = 300)


write.csv(x = df_long, file = "../(Enter directory for output)/Sample_A_Sample_B/raw_cluster_numbers.csv")

```


```{r}
library(tidyr)
library(dplyr)
library(ggplot2)

# Reshape the data frame from wide to long format
df_long <- tidyr::gather(Seurat_Merged_cells, key = "Cluster", value = "ClusterNumber", -sample)

# Calculate total cell counts per sample
df_long <- df_long %>%
  group_by(sample) %>%
  mutate(TotalCells = sum(ClusterNumber, na.rm = TRUE))  # add na.rm = TRUE to ignore NA values

# Replace NA values in ClusterNumber with 0
df_long$ClusterNumber[is.na(df_long$ClusterNumber)] <- 0

# Normalize cell numbers by total cells
df_long <- df_long %>%
  mutate(NormalizedNumber = (ClusterNumber / TotalCells) * 100)

# Define the custom breaks
custom_breaks <- seq(0, 100, by = 10)

# Create the plot
plot <- ggplot(df_long, aes(x = sample, y = NormalizedNumber, fill = Cluster)) +
  geom_bar(stat = "identity", position = "dodge") +
  geom_text(aes(label = paste0(round(NormalizedNumber), "%")), vjust = -0.5, position = position_dodge(width = 1)) +  # Add percentage labels on top of bars
  labs(x = "Sample", y = "Normalized Cell Number (%)", fill = "Cluster") +
  theme_minimal() +
  scale_y_continuous(limits = c(0, 100), breaks = custom_breaks)


output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

# Specify the file path and name for saving the plot
file_path <- file.path(output_dir, "cluster_numbers_normalised.png")

# Save the plot as a PNG file
ggsave(filename = file_path, plot = plot, dpi = 300)

write.csv(x = df_long, file = "../(Enter directory for output)/Sample_A_Sample_B/cluster_numbers_normalised.csv")


```



```{r}
output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

# Specify the file path for reading the CSV file
file_path <- file.path(output_dir, "Seurat_Merged_markers.csv")

# Read in the CSV file
data <- read_csv(file_path)

# Define the number of clusters
num_clusters <- n_distinct(data$cluster)

# Specify the output directory
output_dir <- "../(Enter directory for output)/Sample_A_Sample_B"

library(openxlsx)


# Create an Excel workbook object
wb <- createWorkbook()

# Loop over each cluster
for (i in 0:num_clusters) {
  # Filter the data based on cluster number
  cluster_data <- dplyr::filter(data, cluster == i)
  
  # Filter the genes based on p-value and log-fold change criteria
  selected_genes <- dplyr::filter(cluster_data, p_val_adj < 0.05, avg_logFC > 0.5)
  
  # Create a new worksheet for the cluster and add the selected genes
  addWorksheet(wb, sheetName = paste0("Cluster ", i))
  writeData(wb, sheet = paste0("Cluster ", i), selected_genes)
}

# Specify the file path and name for saving the Excel workbook
file_path <- file.path(output_dir, "Sample_A_Sample_B_makers_processed.xlsx")

# Save the Excel workbook
saveWorkbook(wb, file = file_path)

```




```{r}


# Save the matrix data as CSV
mat <- as.data.frame(GetAssayData(Seurat_Merged, "counts"))
mat_file <- file.path(output_dir, "Sample_A_Sample_B_matrix.csv")
write.csv(mat, file = mat_file)

# Fetch and save the labels as CSV
Labels <- FetchData(Seurat_Merged, vars = c("cells", "seurat_clusters", "orig.ident"))
labels_file <- file.path(output_dir, "Sample_A_Sample_B_labels.csv")
write.csv(Labels, file = labels_file)

```