So far, scientists have identified a handful of genes--such as those that make insulin and interferon--and caused them to produce these products in bacteria. But researchers have barely scratched the surface: If each of the four building blocks--called nucleotides, which combine to form genes--were considered a letter and each gene a word, the genes in a single human cell would fill 13 sets of the Encyclopedia Britannica, says Dr. Victor A. McKusick, director of the department of medicine at Johns Hopkins Medical Institution.

Business Week, Jan 23, 1984--"Biotech Comes of Age" p94 #2825

With the help of my son's research, I found out the average number of cells in the human body and then went to the library and measured the volume of a set of the Encyclopedia Britannicas. I multiplied that volume times 13 times the number of human cells. I found that each human body had enough information in it to cover the Los Angeles Basin 1/4 mile deep in Encyclopedias.

Genetic information in all life is contained in coiled strands of deoxyribonucleic acid (DNA). DNA is organized into small units called genes, which are bundled into much larger units called chromosomes. Humans have about 100,000 genes in 23 pairs of chromosomes. DNA is composed of four distinct chemicals called bases. These bases are strung together sequentially to form genes and chromosomes in the same fashion that letters of the alphabet combine to form words, sentences and books.

If the DNA in one human cell could be uncoiled and stretched out in a straight line, it would be about eight feet long. But if it were enlarged so that each base was the size of a letter in this article, the DNA would form a huge sentence 4,700 miles long, stretching from Los Angeles to Jacksonville, FLA., and back again. So far, researchers have sequenced about 12 million genes, about 19 miles worth.

Shared by Gayle D. Erwin