The “thread of life”, is deoxyribonucleic acid, otherwise known as DNA. It is the spiral shaped molecule found in the nucleus of cells. Scientists haveknown since 1952 that DNA is the basic substance of heredity.
This washypothesized, and later confirmed by James D. Watson and Francis Crick. Theyalso know that it acts like a biological computer program over 3 billion bitslong that “spells” out instructions for making the basic building blocks of life. DNA carries the bodies genetic code, controls the development of an embryo,is capable of duplicating itself, and is able to repair damage to itself.
DNAcan be manipulated to change all kinds of things. All DNA molecules consist of a linked series of unites callednucleotides. Each DNA nucleotide is composed of 3 subunits: a 5 carbon sugarcalled deoxyribose, a phosphate group that is joined to one end of the sugarmolecule, and one of several different nitrogenous bases linked to the oppositeend of the deoxyribose. There are 4 nitrogen bases called adenine, guanine,thymine, and cytosine.
In DNA adenine pairs with thymine and guanine withcytosine. Medicine’s ability to diagnose continues to exceed its ability to treator cure. For example, Huntington’s Chorea is an inherited disease that developsbetween the ages of 30 and 45, can be diagnosed before any symptoms appear. This can be hard for both the individuals with the disease and their family. There is a 3 billion dollar project underway right now called the HumanGenome Project, a 15 year program to make a detailed map of every single gene inhuman DNA.
With automated cloning equipment to steer scientists through the DNA,scientists are finding human genes at the rate of more than one a day. This maynot sound like very much but as technology increases the rate at finding themwill increase. Since January 1993 to January 1994 scientists have located thegenes for Huntington’s disease, Lou Gehrig’s disease, and the “bubble-boy”disease. Scientists are expected to find the first breast cancer gene any weeknow. Even with the best tools of today, the progress is full of surprises. Human DNA is not like that of plants, in which the trait of color of a flower isdetermined by one gene.
Even the color of a human eye can involve theinteraction of several genes. Some complex genes, such as cystic fibrosis, cango wrong in any number of places. Scientists have already accounted for 350places where the cystic fibrosis gene mutates, and more are being uncoveredweekly. Many environmental factors, some physical, other’s chemical, can alterthe structure of a DNA molecule. A mutation occurs when such alterations leadto a permanent change in the base sequence of a DNA molecule.
Mutations resultin an inherited change in a protein synthesis. DNA is damaged by exposure toultraviolet (UV) light. The DNA does have the ability to repair it self,however. DNA can also be used to match suspects in a crime.
Each person’s DNA isdifferent from everyone else, except in the case of identical twins in which itis identical. By comparing substances left at a crime scene (blood or semensamples) law enforcement agencies are able to match the DNA at the crime scenewith a certain suspect. A recent example of this is the O. J. Simpson case, inwhich the lawyers are trying to match up O. J.
‘s DNA with the DNA in the bloodfound at the crime scene. Many questions have been raised by a number of people and scientistsabout the ethics of DNA research. It was once feared that the insertion of adisease causing substance could cause a deadly epidemic in the generalpopulation upon accidental release. But, since 1973 when they first used thetechnique it has been transferred thousands of times without any of the fearedcatastrophes occurring. But, still there are many questions remaining to beanswered.
Is it right for people to change their babies’ eye color, or anyother aspect of their baby’should employers be allowed to see your DNA, to seeif you are at risk for a certain disease? Category: Science
