Download The `thread of life`, is deoxyribonucleic acid, otherwise known as

The 'thread of life', is deoxyribonucleic acid, otherwise known as DNA. It is the
spiral shaped molecule found in the nucleus of cells. Scientists have known since 1952
that DNA is the basic substance of heredity. This was hypothesized, and later confirmed
by James D. Watson and Francis Crick. They also know that it acts like a biological
computer program over 3 billion bits long 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. DNA can be manipulated to
change all kinds of things.
All DNA molecules consist of a linked series of unites called nucleotides. Each
DNA nucleotide is composed of 3 subunits: a 5 carbon sugar called deoxyribose, a
phosphate group that is joined to one end of the sugar molecule, and one of several
different nitrogenous bases linked to the opposite end of the deoxyribose. There are 4
nitrogen bases called adenine, guanine, thymine, and cytosine. In DNA adenine pairs
with thymine and guanine with cytosine.
Medicine's ability to diagnose continues to exceed its ability to treat or cure. For
example, Huntington's Chorea is an inherited disease that develops between 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 Human Genome
Project, a 15 year program to make a detailed map of every single gene in human 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 may not sound like very
much but as technology increases the rate at finding them will increase. Since January
1993 to January 1994 scientists have located the genes for Huntington's disease, Lou
Gehrig's disease, and the 'bubble-boy' disease. Scientists are expected to find the first
breast cancer gene any week now.
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 is determined by one gene.
Even the color of a human eye can involve the interaction of several genes. Some
complex genes, such as cystic fibrosis, can go wrong in any number of places. Scientists
have already accounted for 350 places where the cystic fibrosis gene mutates, and more
are being uncovered weekly.
Many environmental factors, some physical, other's chemical, can alter the
structure of a DNA molecule. A mutation occurs when such alterations lead to a
permanent change in the base sequence of a DNA molecule. Mutations result in an
inherited change in a protein synthesis. DNA is damaged by exposure to ultraviolet (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 is
different from everyone else, except in the case of identical twins in which it is identical.
By comparing substances left at a crime scene (blood or semen samples) law enforcement
agencies are able to match the DNA at the crime scene with a certain suspect. A recent
example of this is the O.J. Simpson case, in which the lawyers are trying to match up
O.J.'s DNA with the DNA in the blood found at the crime scene.
Many questions have been raised by a number of people and scientists about the
ethics of DNA research. It was once feared that the insertion of a disease causing
substance could cause a deadly epidemic in the general population upon accidental
release. But, since 1973 when they first used the technique it has been transferred
thousands of times without any of the feared catastrophes occurring. But, still there are
many questions remaining to be answered. Is it right for people to change their babies'
eye color, or any other aspect of their baby? Should employers be allowed to see your
DNA, to see if you are at risk for a certain disease?
Keywords:
thread life deoxyribonucleic acid otherwise known spiral shaped molecule found nucleus
cells scientists have known since that basic substance heredity this hypothesized later
confirmed james watson francis crick they also know that acts like biological computer
program over billion bits long that spells instructions making basic building blocks life
carries bodies genetic code controls development embryo capable duplicating itself able
repair damage itself manipulated change kinds things molecules consist linked series
unites called nucleotides each nucleotide composed subunits carbon sugar called
deoxyribose phosphate group joined sugar molecule several different nitrogenous bases
linked opposite deoxyribose there nitrogen bases called adenine guanine thymine
cytosine adenine pairs with thymine guanine with cytosine medicine ability diagnose
continues exceed ability treat cure example huntington chorea inherited disease develops
between ages diagnosed before symptoms appear this hard both individuals with disease
their family there billion dollar project underway right human genome project year
program make detailed every single gene human automated cloning equipment steer
scientists through scientists finding human genes rate more than this sound like very
much technology increases rate finding them will increase since january january have
located genes huntington disease gehrig bubble expected find first breast cancer gene
week even best tools today progress full surprises like plants which trait color flower
determined gene even color involve interaction several genes some complex such cystic
fibrosis wrong number places have already accounted places where cystic fibrosis
mutates more being uncovered weekly many environmental factors some physical other
chemical alter structure molecule mutation occurs when such alterations lead permanent
change base sequence mutations result inherited change protein synthesis damaged
exposure ultraviolet light does ability repair self however also used match suspects crime
each person different from everyone else except case identical twins which identical
comparing substances left crime scene blood semen samples enforcement agencies able
match crime scene certain suspect recent example simpson case which lawyers trying
match blood found scene many questions been raised number people about ethics
research once feared insertion causing substance could cause deadly epidemic general
population upon accidental release since when they first used technique been transferred
thousands times without feared catastrophes occurring still there many questions
remaining answered right people their babies color other aspect their baby should
employers allowed your risk certain
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