marker.genes.2 <- list(
  Gene1 = c(1, 2, 3),
  Gene2 = c(4, 5, 6, 7),
  Gene3 = c(8, 9, 10)
)

# Find the maximum length among all vectors
max_length <- max(sapply(marker.genes.2, length))

# Pad shorter vectors with NA to make them consistent
marker.genes.2 <- lapply(marker.genes.2, function(x) {
  if (length(x) < max_length) {
    c(x, rep(NA, max_length - length(x)))
  } else {
    x
  }
})

# Create a data frame from the corrected list
my_data_frame <- data.frame(marker.genes.2)

# Display the resulting data frame
print(my_data_frame)