4 Million Switches to Control 20,000 Genes: An Ongoing Revolution in Biology
The human genome is packed with at least 4 million gene switches that reside in bits of DNA that once were dismissed as junk but that turn out to play critical roles in controlling how cells, organs, and other tissues behave. The discovery, considered a major medical and scientific breakthrough, has enormous implications for human health because many complex diseases appear to be caused by tiny changes in hundreds of gene switches.
The findings are the fruit of an immense federal project, involving 440 scientists from 32 global labs. As they delved into the junk — parts of the DNA that are not actual genes containing instructions for proteins — they discovered it is not junk at all. At least 80 percent of it is active and needed. _BG
Just when the educated public thought it was beginning to understand how cells work, they are told that the mechanisms of life are orders of magnitude more complex than they previously believed.
The secret to complex life is not just the mechanisms of DNA transcription to RNA, and RNA tranlation to proteins. Complex life is an astounding swirl of circular logic and control circuits of cell signaling. Some genes are constantly being switched on and off, while other genes are silenced permanently or over long periods of time.
But we are discovering ways to alter the natural order of cell signaling and gene switching -- and that ability to change the natural scheme of things amounts to a building revolution in our biological world.
Here is a quick example of a discovery in cell switching which may lead to the ability to quickly repair damage to heart muscle from hear attacks:
MicroRNAs are short segments of RNA whose purpose is to cause genes to switch on and off. To find out which ones are responsible for causing heart cells to divide, the team studied 875 of them taken from a human heart and implanted into rodent muscle. In so doing they found 204 of them that reactivated cell proliferation and 40 and that did so strongly. They then chose the two strongest and injected them into the hearts of live mice that had been caused to suffer damage to their hearts, using a harmless virus as a carrier.Abstract of study in Nature
After two weeks, the mice that had been injected with the MicroRNAs showed less damage than prior to the treatment, indicating regeneration had occurred. After two months, the damaged tissue area had been reduced by half. The team also noted that contraction strength improved as did other heart functions that were measured.
The research team concludes by suggesting that their method of using MicroRNAs to induce regeneration of damaged heart tissue might be used someday soon to treat heart attack victims... _MXP
Heart disease is the primary cause of death in most developed countries. The ability to rapidly heal heart muscle damage after heart attacks would likely prolong the productive lives of hundreds of thousands of people in the developed world every year.
Cell switching effects of micro RNA and Transcription Factor networks (PDF)
When we consider a world where humans have achieved the mastery of cell signaling and gene switching, we are not necessarily looking at a world of immortal, universally brilliant, and physically powerful humans. We should look at these things in relative terms, rather than in absolutes. Compared to monkeys, humans are longer-lived and quite capable in a broader range of activities and environments.
Likewise, compared to modern humans, those future people who have achieved mastery over biology will live longer lives, and possess a significantly broader range of aptitudes and capabilities over a greater number of environments.
Biology has its shortcomings, of course. We are likely to discover ways of bypassing and substituting for, much of the evolved complexity of biological cells, organs, and organisms for the sake of improved reliability.
But that will have to be done in a carefully considered and cautious manner. We have to be sure that we do not sacrifice too much resiliency for the sake of reliability within a narrow niche of functioning. No one wants to be a Dodo bird.