By Lubna Abdel-Aziz So you thought it was all in the genes you inherited! Your appearance, your mannerisms, the diseases you developed - so did we all, for over a century. Now we discover we were wrong. Our genes do not determine our hereditary traits, despite the countless hours of diligent studies and exhaustive calculations of Gregor Johann Mendel (1822 -- 1884). An industrious Austrian monk, it was Mendel's experiment with the breeding of garden peas that led to the development of the science of genetics. Mendel's study was published in 1866 but it remained unnoticed for 34 years until it was discovered in 1900. Ever since, scientists have regarded the "gene" as the basis of inherited traits. A century later Mendel's theory has been dismissed as pure fiction. What then is the basis of our hereditary characteristics? Far, far more complex than that of garden peas! It is the result of an incredibly elaborate "interplay among the different components of the genome, scattered among many different genes." Surprisingly genes account for only 2% of the human genome. Why then did they name it 'genome', leading us to believe our make-up wholly depends on our genes? The rest of the 98% of DNA did not appear to have any function or meaningful 'raison d'etre' and was often called "junk DNA." Was the elation for naught? What happened to the greatest revelation of our age, which would soon cure all ills? The genome map provided the sequences of all our genes, but did not tell us how they work. It was much like finding all the pieces of a puzzle, but not how to put it together. Now they are claiming with more certainty than ever, what was often claimed before, that comprehensive understanding of the human machine is within our grasp. Have we not heard all this before! What should give us reason for excitement now? Geneticists are finally putting the pieces of the puzzle in place. By abandoning their preconceived notions of genes, geneticists, looked instead at the individual letters or "bases" in the DNA (A, C, T, & G), that make up the genome. They immediately began to see cause and effect connections to numberless diseases and human traits. Armed with this new knowledge, will we therefore be able to prevent or treat major diseases? From April to August geneticists at Harvard and MIT (Massachusetts Institute of Technology), put their heads together, creating the Broad Institute, and in conjunction with the Icelandic company deCODE Genetics, as well as many other insitutions, have identified alterations in the sequences of DNA that cause such diseases as: diabetes I & II, schizophrenia, bipolar disorder, glaucoma, inflammatory bowel disease, rheumatoid arthritis, hypertension, restless leg syndrome, susceptibility to gall stone formation, lupus, multiple sclerosis, heart disease, colon rectal and prostate cancer, and susceptibility to AIDS. Will all these diseases be treatable soon? Practically speaking, all it means is that after years of chasing false leads, gene hunters feel that they have finally cornered their prey. This, according to the two top leading scientific journals, the British Science Journal and its American counterpart. Are we therefore no longer to suffer the slings and arrows of outrageous disease? No! All that scientists have accomplished is that they have decisively met the enemy. Scientists are perhaps able to prevent disease, proving once again "prevention is better than cure", certainly more achievable. Very soon your doctor will run an efficient complete analysis of your personal genome with a detailed profile of your health hazards. And here we thought that was the purpose of the 'genome map!' Scientists did too. But after they hit a brick wall, they went back to the drawing board and started investigating further. Geneticist Philip Sharp and Richard Roberts found that the DNA usually contained in the corresponding gene, was in fact often split throughout the genome. A Nobel prize was awarded them in 1993 for their breakthrough discovery. Then came the visionary geneticist Leroy Hood who recognized the basic simplicity of DNA and proteins; DNA is made up of four chemical letters or "bases" A, C, G, &T, and all proteins are derived from 21 amino acids. With such basic simplification could not robots and computers do the work of thousands of scientists toiling methodically day and night at a slower pace, with little productivity? Robots were faster, cheaper and more accurate. Despite reluctance and suspicion in the scientific community, Hood miraculously executed his plan. The development of the DNA reading machines suddenly cracked the 3 billion base sequence of our entire genome within three years. From then on progress accelerated to a mind boggling degree. Another genetic duo Andrew Fine and Craig Melo discovered a mechanism that had been hitherto overlooked -- RNA interference (RNAi). Tens of thousands of the so-called 'junk DNA' directed the production of specific molecules called micro RNA (miRNAs) which modulated the expression of DNA. It became clear that the fundamental unit of heredity was not the gene but the position of each DNA letter. Of the 3 billion DNA bases in the human genome, geneticists identified one tenth of one percent (millions) that differ from one person to another. So how do we now determine heredity if not by the gene? By variations in the particular letter called Single Nucleotide Polymorphisms, SNPs ("snips"). For the discovery of our "snips" Fine and Melo received the Nobel Prize in 2006. Another visionary geneticist Kari Stefansson, left his position at Harvard and returned to his homeland Iceland, after deducing correctly that to find the cause of diseases one would require the participation of very large groups of related people. He used his family and 100,000 Icelandic volunteers who could trace their ancestry to the Vikings. As of September his company deCODE Genetics has identified "snips" that may play a role in 28 common diseases, including glaucoma, diabetes, cancer and heart disease. This explosive scientific revolution is equally overwhelming and momentous as the one pioneered by physicist Albert Einstein in 1905, known as the annus mirabilis of the 20th century. 2007 may well be the annus mirabilis of the 21st century. The discovery of "snips" replacing genes is once again turning many heads, as did the genetic theory of the hard working meticulous monk Gregor Mendel, last century. We apologize to our diligent monk, who worked indefatigably to establish the genetic theory. Being the real scientist we know he was, he must be rejoicing in heaven that perhaps, and at long last, children born today, will not endure the ravages of Cancer and its deadly sisters, tomorrow. Dare we hope? We dare! When we are planning for posterity, we ought to remember that virtue is not hereditary -- Thomas Paine (1737 -- 1809)
