Most genes in the human genome are, recall, interrupted by stretches of DNA called introns, which are like garbled stuffers placed in between parts of a message. Rather than the word genome, the actual gene reads gen . . . . . . . . . om . . . . . . e. The introns in human genes are often enormous, stretching across vast lengths of DNA, making it virtually impossible to clone a gene directly (the intron-containing gene is too long to fit into a bacterial plasmid).
