| DNA, Gene, Genetic Diseases, Mutation |
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PHYTONUTRIENTS AND DRUG PRODUCTS. THIS WEBSITE ALSO TALKS ABOUT SOME POPULAR HEALTH ISSUES AND
DISEASES. ARTICLES IN THIS WEB SITE IS FOR YOUR REFERENCE ONLY. IF YOU HAVE ANY QUESTION, YOU SHOULD
CONSULT WITH YOUR DOCTOR IMMEDIATELY. ALL RIGHTS RESERVED. DO NOT COPY NOR TRANSFER ARTICLES TO
OTHER WEBSITES NOR OTHER FORMS OF PUBLICATIONS. Privacy Policy. ARTICLE INDEX/ Science
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DNA DNA is a vast chemical information database. It resides in the core, or nucleus, of each
of the body's trillions of cells, and it carries the complete set of instructions for making all the
proteins a cell will ever need. DNA exists as two long, paired strands spiraled into the famous
double helix.
Each strand is made up of millions of chemical building blocks called bases. There are only
four different chemical bases in DNA (adenine, thymine, cytosine, and guanine), but they can
be arranged and rearranged in countless ways. The order in which the bases occur
determines the messages to be conveyed, much as specific letters of the alphabet combine
to form words and sentences.
Every human cell (with the exception of mature red blood cells, which have no nuclei) contains
the same DNA. Each cell has 46 molecules of double-stranded DNA. Each DNA molecule is
made up of 50 to 250 million bases housed in a chromosome.
Gene A gene is a working subunit of a DNA molecule. A gene is any given segment along
the DNA carrying a particular set of instructions that allows a cell to produce a specific
product--typically, a protein such as an enzyme. There are about 25,000 genes, and every
gene is made up of thousands, even hundreds of thousands, of chemical bases.
Building Proteins Building proteins lies at the heart of cell function. For a cell to make a
protein, the information from a gene is copied, base by base, from a strand of DNA into a
strand of messenger RNA. Messenger RNA travels out of the nucleus into the cytoplasm, to
cell organelles called ribosomes. There, messenger RNA directs the assembly of amino
acids that fold into a completed protein molecule.
Gene and Its Functions Although each cell contains the genetic potential to make all
possible human proteins, cells use genes selectively. Some housekeeping genes encode
proteins needed for basic cell functions, and these genes stay active all the time in many cell
types. More typically, though, a cell activates just the genes it needs at the moment and
actively suppresses the rest. The unique selection of genes used by a cell gives that cell its
character--making a brain cell, say, different from a bone cell.
Genetic Diseases A sound body depends on the continuous interplay of thousands of
proteins, acting together in just the right amounts and in just the right places--and each
properly functioning protein is the product of an intact gene.
Many, if not most, diseases have their roots in our genes. More than 4,000 diseases stem
from altered genes inherited from one's mother and/or father. Common disorders such as
heart disease and most cancers arise from a complex interplay among multiple genes and
between genes and factors in the environment.
Mutation Genes can be altered, or mutated, in many ways. The most common gene change
involves a single base mismatch--a misspelling--placing the wrong base in the DNA. At other
times, a single base may be dropped or added. And sometimes large pieces of DNA are
mistakenly repeated or deleted.
When a gene contains a mutation, the protein encoded by that gene is likely to be abnormal.
Sometimes the protein will be able to function, but imperfectly. In other cases, it will be totally
disabled. The outcome depends not only on how it alters a protein's function but also on how
vital that particular protein is to survival.
Hereditary Mutation Gene mutations can be either inherited from a parent or acquired.
Hereditary mutations are carried in the DNA of the reproductive cells. When reproductive
cells containing mutations combine to produce offspring, the mutation will be in all of the
offspring's body cells. The fact that every cell contains the gene change makes it possible to
use cheek cells or a blood sample for gene testing.
Acquired Mutation Acquired mutations are changes in DNA that develop throughout a
person's lifetime. Although mistakes occur in DNA all the time, especially during cell division,
a cell has the remarkable ability to fix them. But if DNA repair mechanisms fail, mutations can
be passed along to future copies of the altered cell.
A Few Examples of Diseases Related to Genes Autism is not just a single disease but
can be caused by a range of genetic and environmental factors. The risk factors include
female gender, aging, personal history of breast cancer, family history of breast cancer,
genetic factors (cancer causing mutations in BRCA1 (BReast CAncer gene 1) and BRCA2
(BReast CAncer gene 2), and hormonal factors (as earlier age at first period, later age at
birth of first child, later age at menopause, having no children). Turner syndrome is a disorder
of the sex chromosomes.
Gene Therapy Three genes that produce dopamine were inserted into a disabled equine
virus that was then injected into the brain. Six human volunteers began clinical trials a year
ago, and the results are "extremely encouraging," as measured in control of Parkinson's
symptoms and in side effects such as brain inflammation.
SOURCE: National Cancer Institute, www.cancer.gov
of the body's trillions of cells, and it carries the complete set of instructions for making all the
proteins a cell will ever need. DNA exists as two long, paired strands spiraled into the famous
double helix.
Each strand is made up of millions of chemical building blocks called bases. There are only
four different chemical bases in DNA (adenine, thymine, cytosine, and guanine), but they can
be arranged and rearranged in countless ways. The order in which the bases occur
determines the messages to be conveyed, much as specific letters of the alphabet combine
to form words and sentences.
Every human cell (with the exception of mature red blood cells, which have no nuclei) contains
the same DNA. Each cell has 46 molecules of double-stranded DNA. Each DNA molecule is
made up of 50 to 250 million bases housed in a chromosome.
Gene A gene is a working subunit of a DNA molecule. A gene is any given segment along
the DNA carrying a particular set of instructions that allows a cell to produce a specific
product--typically, a protein such as an enzyme. There are about 25,000 genes, and every
gene is made up of thousands, even hundreds of thousands, of chemical bases.
Building Proteins Building proteins lies at the heart of cell function. For a cell to make a
protein, the information from a gene is copied, base by base, from a strand of DNA into a
strand of messenger RNA. Messenger RNA travels out of the nucleus into the cytoplasm, to
cell organelles called ribosomes. There, messenger RNA directs the assembly of amino
acids that fold into a completed protein molecule.
Gene and Its Functions Although each cell contains the genetic potential to make all
possible human proteins, cells use genes selectively. Some housekeeping genes encode
proteins needed for basic cell functions, and these genes stay active all the time in many cell
types. More typically, though, a cell activates just the genes it needs at the moment and
actively suppresses the rest. The unique selection of genes used by a cell gives that cell its
character--making a brain cell, say, different from a bone cell.
Genetic Diseases A sound body depends on the continuous interplay of thousands of
proteins, acting together in just the right amounts and in just the right places--and each
properly functioning protein is the product of an intact gene.
Many, if not most, diseases have their roots in our genes. More than 4,000 diseases stem
from altered genes inherited from one's mother and/or father. Common disorders such as
heart disease and most cancers arise from a complex interplay among multiple genes and
between genes and factors in the environment.
Mutation Genes can be altered, or mutated, in many ways. The most common gene change
involves a single base mismatch--a misspelling--placing the wrong base in the DNA. At other
times, a single base may be dropped or added. And sometimes large pieces of DNA are
mistakenly repeated or deleted.
When a gene contains a mutation, the protein encoded by that gene is likely to be abnormal.
Sometimes the protein will be able to function, but imperfectly. In other cases, it will be totally
disabled. The outcome depends not only on how it alters a protein's function but also on how
vital that particular protein is to survival.
Hereditary Mutation Gene mutations can be either inherited from a parent or acquired.
Hereditary mutations are carried in the DNA of the reproductive cells. When reproductive
cells containing mutations combine to produce offspring, the mutation will be in all of the
offspring's body cells. The fact that every cell contains the gene change makes it possible to
use cheek cells or a blood sample for gene testing.
Acquired Mutation Acquired mutations are changes in DNA that develop throughout a
person's lifetime. Although mistakes occur in DNA all the time, especially during cell division,
a cell has the remarkable ability to fix them. But if DNA repair mechanisms fail, mutations can
be passed along to future copies of the altered cell.
A Few Examples of Diseases Related to Genes Autism is not just a single disease but
can be caused by a range of genetic and environmental factors. The risk factors include
female gender, aging, personal history of breast cancer, family history of breast cancer,
genetic factors (cancer causing mutations in BRCA1 (BReast CAncer gene 1) and BRCA2
(BReast CAncer gene 2), and hormonal factors (as earlier age at first period, later age at
birth of first child, later age at menopause, having no children). Turner syndrome is a disorder
of the sex chromosomes.
Gene Therapy Three genes that produce dopamine were inserted into a disabled equine
virus that was then injected into the brain. Six human volunteers began clinical trials a year
ago, and the results are "extremely encouraging," as measured in control of Parkinson's
symptoms and in side effects such as brain inflammation.
SOURCE: National Cancer Institute, www.cancer.gov