Moore's law, says that, the density of integrated chips should double every six months. Unfortunately, there is a limit to how many transistors you can cram into a finite volume. Scientists are now exploring quantum computing. Quantum computing uses the quantum mechanical states of atoms to represent information. The spin of an electron can be up or down ( +1/2 or –1/2). Imagine being able to control the spin states of an electron in an atom, or a molecule. You could have huge processing capabilities. That seems to be the next frontier for computers.
Neil Gerchenfeld of MIT and Isaac Chung of Los Alamos National Laboratory have brought this closer to reality by adding two numbers, using Nuclear Magnetic Resonance to flip the nuclear spins of the organic molecule, alanine. In March 1997, they
took atoms embedded in a large molecule and used the direction of their spins to represent data. The heart of the two physicist's computer is a thimbleful of the organic chemical, alanine. The trillions and trillions of atoms in that thimble, point in every other way, but a tiny plurality of them can be found pointing in a specific direction. These atoms which stand out to the NMR machine, because the spins of the other, randomly pointing atoms, cancel on another, constitute one quantum bit, or quibit. The alanine molecule, it turns out, yields three quibits because it has 3 atoms of carbon that each corresponds to a different NMR frequency, and yet the atoms are linked in such a way that they can be used for addition. The physicists used just two of the carbon atoms to add one plus one together. The atoms were the quantum computer's hardware; its software program was the radio pulse the researchers nudged the atoms with. Each pulse made one atom in the pair (the “target”) shift the orientation of its spin, in a way that depended on both the duration of the pulse- say, one-hundredth of a second for a quarter turn- and on the orientation of the partner atom, the (“control”). When the program was finished, the final spin state of the atoms, gave the answer- two, in this case. They have been able to apply this device to pick out a telephone number out of a list of four other numbers (sorting). The great potential of quantum computing lies in their theoretical ability to perform lots of calculations at once (huge parallel processing), which stems from the fact, that atoms, according to quantum mechanics, exist in an infinite number of states until they are measured.
THE HUMAN GENOME PROJECT: J.C. VENTER INTENDS TO WIN THE RACE......
October 8 1999
Source: The New York Times Magazine / August 23, 1998.
It is about two years since this article appeared in the New York Times Magazine.
According to Craig Venter's prediction, he was going to complete the human genome project by 2001, four year ahead of schedule. He would thus beat out all the scientists at the National Institute of health by four years. This put a lot of pressure on all genomic scientists funded by the NIH and other funding agencies like the department of energy. The implication being that, the $3 billion earmarked for this project was just a waste of public money. Craig Venter says he will do it for $300 million.
Fig. 1. DNA Structure.
The four nitrogenous bases of DNA are arranged along the sugar- phosphate backbone in a particular order (the DNA
sequence), encoding all genetic instructions for an organism. Adenine (A) pairs with thymine (T), while cytosine (C) pairs with
guanine (G). The two DNA strands are held together by weak bonds between the bases.
A gene is a segment of a DNA molecule (ranging from fewer than 1 thousand bases to several million), located in a particular
position on a specific chromosome, whose base sequence contains the information necessary for protein synthesis.
There is a lot of money involved here and that is what makes the whole issue so controvesial.
While the rest of the world is either sleeping or fighting useless wars, a group of scientists are involved in a project that affects directly, the future of the human race.
What is the human genome, one might ask ?
Introduction:
The complete set of instructions for making an organism is called its genome. It contains the master blueprint for all cellular structures and activities for the lifetime of the cell or organism. The human genome consists of tightly coiled threads of deoxyribonucleic acid (DNA) and associated protein molecules, organised into structures called chromosomes. The genome is located in the nucleus of every cell. Humans have trillions of cells. If unwound and tied together, the strands of DNA would stretch more than 5 feet but would only be 50 trillionths of an inch wide. For each organism, the components of these slender threads encode all the information necessary for building and maintaining life, from simple bacteria to complex human beings. Understanding how DNA performs this function requires some knowledge of its structure and organisation.
DNA:
In humans, as in other higher organisms, a DNA molecule consists of two strands that wrap around each other to resemble a twisted ladder ( double helix) whose sides, made of sugar and phosphate molecules, are connected by rungs of nitrogen containing chemicals called bases. Each strand is a linear arrangement of repeating similar units called nucleotides, which are each composed of one sugar, one phosphate, and a nitrogenous base. Four different bases are present in DNA: Adenine (A), thymine (T), cystosine (C) and guanine, (G). The particular order of the bases arranged along the the sugar-phosphate backbone is called the DNA sequence.
Fig. 2 (above). The Human Genome at Four Levels of Detail.
Apart from reproductive cells (gametes) and mature red blood cells, every cell in the human body contains 23 pairs of
chromosomes, each a packet of compressed and entwined DNA (1, 2). Each strand of DNA consists of repeating nucleotide
units composed of a phosphate group, a sugar (deoxyribose), and a base (guanine, cytosine, thymine, or adenine) (3).
Ordinarily, DNA takes the form of a highly regular double- stranded helix, the strands of which are linked by hydrogen bonds
between guanine and cytosine and between thymine and adenine. Each such linkage is a base pair (bp); some 3 billion bp
constitute the human genome. The specificity of these base- pair linkages underlies the mechanism of DNA replication illustrated
here. Each strand of the double helix serves as a template for the synthesis of a new strand; the nucleotide sequence (i.e., linear
order of bases) of each strand is strictly determined. Each new double helix is a twin, an exact replica, of its parent. (Figure and
caption text provided by the LBL Human Genome Center.)
The sequence specifies the exact genetic instructions to create a particular organism with its own unique traits. Thus you can specify blue eyes, blond hair etc , etc if you can read the code and change it !!
Fig. 3 (above). DNA Replication.
During replication the DNA molecule unwinds, with each single strand becoming a template for synthesis of a new,
complementary strand. Each daughter molecule, consisting of one old and one new DNA strand, is an exact copy of the parent
molecule. [Source: adapted from Mapping Our Genes The Genome Projects: How Big, How Fast? U.S. Congress, Office of
Technology Assessment, OTA- BA- 373 (Washington, D.C.: U.S. Government Printing Office, 1988).]
The two DNA strands are held together by weak bonds between the bases on each strand, forming base pairs (bp). Genome size is usually stated as the total number of base pairs. The human genome contains roughly 3 billion base pairs. Using very fast computers and automated sequence analyzers from the Perkin Elmer instrument company, Venter hopes to determine enough f these base pairs to read the code.
Genes:
Each DNA molecule contains many genes, the basic physical and functional units of heridity. A gene is a specific sequence of nucleotide bases, whose sequences carry the information required for constructing proteins. Proteins provide the strcutural components of cells and tissues as well a enzymes for essential biochemical reactions. The human genome is estimated to comprise 80,000 to 100,000 genes.
Fig. 4. Gene Expression.
When genes are expressed, the genetic information (base sequence) on DNA is first transcribed (copied) to a molecule of
messenger RNA in a process similar to DNA replication. The mRNA molecules then leave the cell nucleus and enter the
cytoplasm, where triplets of bases (codons) forming the genetic code specify the particular amino acids that make up an
individual protein. This process, called translation, is accomplished by ribosomes (cellular components composed of proteins
and another class of RNA) that read the genetic code from the mRNA, and transfer RNAs (tRNAs) that transport amino acids
to the ribosomes for attachment to the growing protein.
Ethical Issues
Venter and associates intend to patent the human genes as they discover them. This is in order to rrecoup their investment and reap unlimited financial rewards. Does anybody have the right to patent human genes ? About two years ago, a pharmaceutical company, tried to patent an insecticide from the Nim tree. Indian scientists raised enough noise to stop them.
We have only about two more years according to Venter's prediction. The field of Genomic Science is so new, that the scientists involved in this area are making up the terminology as they go along.
The potential medical applications are so vast that it will make today's treatments look as clumsy and archaic as bloodletting and cupping which was practised in the 1500's.
Genes and Disease
The quest for an understanding of how genetic factors contribute to human disease is gathering speed. Forty years ago, the structure of DNA has just been solved and the precise number of human chromosomes was still under debate. The association between Trisnomy 21 and Down's syndrome was on the eve of discovery. We now know that there are 46 human chromosomes which between them house 3000 million base pairs of DNA and encode about 60,000 to 80,000 proteins. These coding regions make up only about 2% of the genome (the function of the remaining 98% is unknown) and some chromosomes have a higher density of genes than others do.
A great deal of effort over the past ten years has been put into creating a physical map of the human genome, ordering genes within the genome by placing landmarks to navigate by. As well as providing an excellent framework for the complete sequencing of the human genome, the physical map has assisted in identifying about 100 disease-causing genes.
One of the most difficult challenges ahead is to find genes involved in diseases that have a complex pattern of inheritance, such as those that contribute to diabetes, asthma, cancer and mental illness. In all these cases, no gene has the yes/no power to say whether a person has a disease or not. It is likely that more than one mutation is required before the disease is manifest. A number of genes may each make a subtle contribution
to the person's susceptibility to a disease; genes may also affect how a person reacts to environmental factors. Unraveling these networks of events will undoubtedly be a challenge for some time to come
Tokyo (Associated Press News) - A small Japanese firm has
developed a short-wavelength laser that could have many practical
applications, including eye surgery and high-definition videos.
Nichia Chemical Industries Ltd, an obscure high-tech firm based in
southern Japan, plans to offer samples of it's blue or violet laser light
to commercial companies as soon as next month, spokesman Kazu Miyazaki
said Wednesday.
Experts say Nichia's breakthrough is the key to developing
high-definition video disks, higher resolution laser printers, more
precise laser surgery and scores of as-of-yet unimagined applications.
The wavelength of Nichia's blue laser-400 nanometers- is about
one-third shorter than that of conventional red-light lasers, allowing it
to blast smaller grooves into CD-ROMS and therefore triple their storage
capacity.
My Comments:
This article from the associated press does not mention the intense and
futile efforts that American Companies and Top Universities, have spent
over the last one and a half years trying to develop a blue laser. Popular
Mechanics (one of the 1997 issues) tells of how this obscure japanese
scientist invented the blue laser. He always demonstrates it on demand,
but he is the only one in the world who knows how to make it.
The first satelite completely designed and built in Africa has been
brought to fruition in south africa. It will be launched this week from a
US rocket. It was built by a university professor and his graduate
students. He was provided the research money by industry. High school
students in south africa are now involved in modem building projects to
communicate with the satelite. Electronics has taken off in a big way in
post apartheid South Africa.
Fig. 3 (above). DNA Replication.
