The human genome contains approximately 20,000 protein-coding genes, yet it has the capacity to produce several hundred thousand gene products. What can account for the vast difference in gene number and product number? The human genome contains approximately 20,000 protein-coding genes, yet it has the capacity to produce several hundred thousand gene products. What can account for the vast difference in gene number and product number? Alternative splicing occurs. There are more introns than exons. There are more exons than introns. Much of the DNA is in the form of trinucleotide repeats, thus allowing multiple start sites for different genes. Every gene can be read in both directions, and each gene can have inversions and translocations.