The Disappearing Genome

The history of estimates of the size of the human genetic material reveals some surprising trends. Initially, biologists estimated that 10 to 30 percent of the human genome codes for protein. Next it was stated that there were about 100,000 genes, each with about 1000 base pairs. This means about 100 million base pairs coding for protein, or about 3 percent of the total genetic material. A recent biology text said that the typical gene has 600 base pairs, and biologists now estimate that the human genome has 70,000 or 80,000 genes. This amounts to about 45 million base pairs coding for protein, or less than 1.5 percent of the total 3.5 billion base pairs in the human genome. The article in Science, 6 Jan. 1995, pp. 35-36 even states that humans have 40,000 genes. It's a good thing that the human genome project is underway to give us a definite figure, because at the current rate it looks like our genetic material could entirely disappear otherwise!

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