# Install and load necessary packages
if (!requireNamespace("BiocManager", quietly = TRUE))
  install.packages("BiocManager")
BiocManager::install("TxDb.Hsapiens.UCSC.hg19.knownGene")
library(TxDb.Hsapiens.UCSC.hg19.knownGene)
library(GenomicRanges)
library(readxl)

# Load the gene annotation database
txdb <- TxDb.Hsapiens.UCSC.hg19.knownGene

# Read gene information and regions of interest from Excel file
gene_data <- read_excel("coverage.xlsx")

# Convert gene information and regions of interest data to GRanges object
regions_gr <- GRanges(
  seqnames = gene_data$chromosome,
  ranges = IRanges(start = gene_data$region_start, end = gene_data$region_end),
  strand = "*",
  region_id = gene_data$region_id,  # Replace with actual column name for region ID
  gene_id = gene_data$gene_id  # Replace with actual column name for gene ID
)

# Extract exon information
exon_info <- exons(txdb)

# Find overlaps between regions and exons
overlap <- findOverlaps(regions_gr, exon_info)

# Extract the overlapping exons
overlapping_exons <- subjectHits(overlap)

# Calculate the width of overlapping exons
exon_widths <- width(exon_info[overlapping_exons])

# Calculate the coverage for each region
coverage <- width(coverage(overlap, weight = TRUE)) / exon_widths

----this is my code but its showing no overlaps found