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CORRESPONDENCE NATURE|Vol 441|29 June 2006

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Seeing is believing as brainreveals its adaptability SIR — It is traditionally accepted thatacquisition of vision must occur in the firstyear or two of life, before the critical periodfor vision has elapsed. We were fascinated,therefore, by your News Feature “Look andlearn” (Nature 441, 271–272; 2006) reportingacquisition of competent vision in PawanSinha’s patient following almost 30 years offunctional blindness, particularly as we haveobserved a similar phenomenon in the morelimited domain of stereo-blindness.

Although stereo-blindness is infinitely lessdisabling than total blindness, it too isgenerally considered to be incorrigible if nottreated in early childhood. Yet we haverecently followed a 50-year-old stereo-blindwoman who, with proper ocular alignment,has been able to achieve full stereopsis,including the perception of random-dotstereograms, after many decades of stereo-blindness (O. Sacks New Yorker 64–73; 19 June 2006).

A critical period for the development ofmany aspects of visual perception remains a valid concept, and every effort should bemade towards early intervention whencompromised vision is detected. Nonetheless,if there is any early vision at all — even suchlimited vision as Sinha’s patient had, or thevery small fusional area that severe esotropicstrabismus may permit, as in our own patient— it seems that islands of cortical functionmay be established, which can be reactivatedand enlarged even decades later, given therequisite optical or surgical help. In such asituation, there is apparently enough corticalplasticity still present in the adult brain toallow, in some people, a full visual recovery. Oliver Sacks*, Ralph M. Siegel†*2 Horatio Street 3G, New York, New York 10014,USA†Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA

Discrete reminder aboutWeismann’s discovery SIR — Like any other science, geneticscherishes its stories about its heroes (“Hard to track” Nature 441, 400; 2006). In hispublished papers (see www.mendelweb.org),and in his letters to Carl von Nägeli (C. Sternand E. R. Sherwood The Origin of Genetics;Freeman, 1966), Gregor Mendel makes nomention of discreteness; and he probablynever thought about it.

Mendel was lucky that the discrete symbolsof algebra agreed with the discrete units ofinheritance. Mendel is the founder ofgenetics for discovering the algebraic laws of

biological inheritance, not discreteness. It was Ronald A. Fisher (The Genetical Theoryof Natural Selection; Clarendon, 1930) whoput Mendel and discreteness on the samepage, creating the modern myth byimplication.

The discreteness of the modern gene wasdescribed by August Weismann as early as1893, in his classic book The Germ Plasm(Scribner’s), which is still in print. In it,Weismann describes units of inheritance, or ‘ids’, as ‘granular’. Fisher was aware ofWeismann’s ids (R. A. Fisher Science Progress21, 159–160; July 1926), and probably wanted to shift credit to his fellowmathematician, Mendel.

In The Germ Plasm, Weismann also republishes a drawing by Theodor Boveri, a co-discoverer of meiosis, showing pairedunits of inheritance arranged in a double row, like beads on a string.William L. Abler Department of Geology, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605, USA

Researchers frustrated bylack of input to NIH policySIR — In the current discussion about the US National Institutes of Health (NIH), itsdirector and its direction1–3, we have heardmuch about the fact that funding willprobably not increase for the foreseeablefuture, and about the many challengesconfronting the organization.

Clearly, where there is adversity, there isopportunity. Thus, one cannot help but agreewith Michael Bishop and Harold Varmus thatthe way forward lies in “making commoncause with the leadership of NIH”2 andjoining forces. Unfortunately, an issue that has been overlooked is exactly how to makethis happen.

Many NIH-funded investigators ‘in thetrenches’ are very unhappy right now, notonly because funding is tight, but alsobecause they are frustrated by a lack of ready access to, or input in to, global fundingdecisions and important policies. I suspectthat if there were more discussion about thesecritical issues, then investigators would bemuch more understanding and even at ease.Instead, it seems as though there is a widecommunication gap between those whomake decisions about funding (Congress andthe NIH leadership) and those who do anddirect so much of the research that thefunding supports (typical scientists).

Many investigators are so busy withresearch, patient care and administrativeduties that time for such exchange is limited.Nonetheless, both the NIH and thebiomedical-research community wouldbenefit from thoughtful, transparent

discussion about biomedical research in theUnited States in a structured forum. It couldeven lead to productive action. Don C. Rockey University of Texas Southwestern Medical Center,5323 Harry Hines Boulevard, Dallas, Texas75390-8887, USA

1. Marks, A. R. J. Clin. Invest. 116, 844 (2006). 2. Science 312, 499 (2006). 3. Nature 441, 17–19 (2006).

Public will fear biologicalaccidents, not just attacks SIR — As one of the few Europeans who took part in the Synthetic Biology 2.0conference in California in May, I read yourEditorial “Policing ourselves” (Nature 441,383; 2006) and News story “Syntheticbiologists try to calm fears” (Nature 441,388–389; 2006) with great interest. Theimpression I received is that syntheticbiologists are trying to alleviate publicconcerns over their research area — but will have serious difficulty in succeeding.

Most discussions in the field about self-regulation are focused on biosecurity — that is, preventing new opportunities forbioterrorists — in an attempt to actproactively and prevent overly restrictiveregulations being imposed by the authorities.But the concerns raised in the open letterfrom civil organizations includingGreenpeace and Genewatch UK deal with the biosafety aspects: in other words, theuncertainties and unintentionalconsequences of synthetic-biology research,as opposed to its deliberate misuse. Althoughbiosafety concerns were discussed at theconference, they are mainly unaddressed inthe self-regulation attempt. Yet they will beincreasingly significant as the synthetic-biology field develops, especially in Europe.

Synthetic biology shares manycharacteristics with other new technologiesregarding public perception of novelty,uncertainty and controllability; we are allaware of the controversy in Europe overgenetically modified crops. This time, weshould be more far-sighted, and proactivelyaddress biosafety concerns as well as ethics,and intellectual-property rights as much as biosecurity. The Synthetic Biology 3.0conference in Zurich next year will be a good opportunity.Markus SchmidtInternational Dialogue and Conflict Management,Abt-Karl Gasse 19/21, 1180 Vienna, Austria

CorrectionThe name of the co-author, John Lancaster, was accidentally left off the Correspondenceletter “‘Referee factor’ would reward a vitalcontribution” (Nature 441, 812; 2006).

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