One of the today’s unanswered questions in developmental biology, is what causes an organism to grow from an egg and acquire the form that it does. The study of how living forms develop and acquire their final shapes occupied much of Goethe’s life, and inspired his theory of forms. Since the discovery of the DNA molecule, biochemists assumed that the book of instructions on how to build an organism was somehow encoded in the human genome. Doubts began to emerge after the human genome project found that the human being — presumably one of nature’s most complex organisms, only had 25,000 genes. A fruit fly has 17,000, and a sea urchin 26,000 genes. Where is the book of instructions? DNA may have the building blocks of life, but does it contain the information on how to assemble the organism? Recently, biophysicists such as Michael Levin, of Tufts University in Medford, Massachusetts, have concluded that bioelectricity plays a key role in the development of organisms. In a recent review article in New Scientist, Levin casts doubt on the role of DNA in this process.
If you were to show someone the completed genome of a creature, and you didn’t allow them to compare it with the genome of something they were familiar with, they would have absolutely no idea what that creature would look like.
Many biologists are looking into the effect that bioelectricity plays in embryonic development, repairing cells, and even telling certain organisms to re-grow lost limbs. The role of bioelectricity is not a new discovery. Researchers such as Galvani in the 1700s, J.C. Bose in the early twentieth century recognised the important part that electricity plays in the growth and development of an organism. In the 1930s, Yale University’s Harold Saxton Burr proposed that bioelectricity is the “organising principle”, contains the instructions on how an organism was to develop. He and earlier authors named this principle the morphogenetic field. The idea was developed further by Rupert Sheldrake with his theory of Morphic Resonance.
New evidence for the role of bioelectricity in determining how organisms develop comes from experiments carried out recently by Levin with flatworms. When cut in two, each part can regenerate by growing either a head or a tail. However, by putting the bisected worms into a bath that inhibits bioelectrical flow, Levin and his associates were able to grow double-headed worms. When the double-headed worms were subsequently cut in two, each half grew a new head, to reproduce the double-headed worm. Levin felt that the experiment clearly showed that the instructions on how the organism was to repair itself, had been tampered by bioelectrical interference. The DNA of the worm had not been tampered with. Somehow the cells remembered the new instructions, delivered through bio-electricity.
The finding clearly not only challenges accepted views of the pivotal role of DNA, but open up avenues for new techniques to help damaged cells regenerate: cures for damaged nerve cells or cancerous cells. However to make more progress, we will have to find the book of instructions, the bioelectric blueprint for the organism. What is its container?
The early concept of a biological organising field such as suggested by Harold Burr and Sheldrake may eventually make its way back way back into developmental biology.