|
| Q: |
Does everybody have the same genes? |
| A: |
Yes. Most genes are exactly the same in all humans,
but each of us has a very small number of genes that are spelled slightly
differently. These tiny differences make up much less than 1 percent
of each person's genetic material (DNA), yet the differences are enough
to create people with different appearances and different health.
The gene differences are usually inherited, so the more closely related
two people are, the more similar their DNA is likely to be. |
| Q: |
What does it mean when someone says you have a
genetic risk? |
| A: |
It means that you have inherited the tendency to develop
a certain illness. Having a genetic risk does not mean that you will
develop a particular condition, but rather that you have a higher
chance of developing it than if you did not have the risk. Your genes
play a big role in determining whether or not you will develop certain
illnesses. If, for instance, your mother's father had a history of
heart disease, you may have inherited that genetic risk from genes
you got from your mother (that she got from her father), much as you
may also have gotten your grandmother's straight or curly hair. But
genes are not the only thing. What you eat, whether and how much you
exercise, and where you live and work are all factors that can profoundly
affect your overall health. |
| Q: |
What is genetics? |
| A: |
Genetics is the study of inheritance. Genes are the
instruction manuals for making building blocks called proteins, and
proteins combine in many ways to create all the parts of our bodies.
Proteins also create unique body features called "traits".
Some traits are visible, like eye color. Others are not, like your
body's ability to fight certain diseases. Scientists who study genetics
are called geneticists. |
| Q: |
How do scientists learn how genes play a role in
our risks for fighting or developing disease? |
| A: |
Your tax dollars, through the National Institutes
of Health, fund medical research in the United States. The National
Institutes of Health provides some of this money to scientists at
universities and medical centers to carry out research to identify
the roles of genes in various diseases. In the laboratory, genetics
researchers often use organisms that can be bred easily and quickly,
like plants, fruit flies, or mice. Scientists breed slightly different
versions of these organisms and watch the outcomes. These experiments
give scientists lots of basic knowledge about genes and diseases,
because humans have many of the same genes as these experimental organisms.
Knowledge about genes involved in diseases helps scientists find ways
to treat, cure, or prevent diseases. |
| Q: |
How do scientists find genes linked
to human diseases? |
| A: |
Researchers link genes to diseases in
two different ways:
Studying a disease. Scientists who are looking
for relationships between genes and a disease often start with the
disease. For example, since some forms of breast cancer run in families,
researchers might suspect that one or more genes plays a part in
causing breast cancer in those families. To test that idea, scientists
would ask family members to participate in a genetics research study
so that researchers could search for a telltale gene spelling or
combination of gene spellings present only in people who have breast
cancer and not in their family members who don't.
Studying genes. Sometimes, earlier research
in laboratory organisms has yielded a lot of basic information leading
scientists to suspect that certain genes and the proteins they produce
might be linked to a particular disease— heart disease, for
example. For the most part, researchers have already figured out
which proteins are important for the proper functioning of the heart.
For example, some of these proteins affect the pumping of the heart
or regulate cholesterol levels in the blood. Scientists analyze
the spellings of the genes that make those proteins and then conduct
studies with DNA from large numbers of people, hoping to find certain
gene spellings— or combinations of spellings— that turn
up over and over again. These spellings could turn out to be predictors
of heart disease.
|
| Q: |
Why do researchers sometimes study ethnic and racial
groups? |
| A: |
Even though everyone's DNA is just a
little different from everyone else's, we all have 99.9 percent of
the same genes! However, since 3 billion chemical "letters"
string together to make up our genes, the one-tenth of 1 percent of
DNA that is different can add up to hundreds of thousands of differences,
most of which have no effect at all. Groups large or small who share
the same ancestry are likely to have a greater number of similar gene
spellings than do more distantly related people. Studying the DNA
from family members— or from populations
in which people share a common ancestry—
reduces the "background noise" among all those tiny genetic
differences. This makes it easier for scientists to pick out the gene
differences, or patterns of differences, linked with disease. Researchers
study genes from people in different population groups to find the
common genetic differences that are unique to certain diseases,
not to particular ethnic or racial groups. Occasionally, however,
scientists do study members of certain ethnic groups to make it easier
to identify genetic differences that are common to those groups. The
gene that is misspelled in Tay-Sachs disease, for example,
was identified in Ashkenazi Jews. |
| Q: |
Have researchers figured out how errors in genes
can cause disease? |
| A: |
Yes, but only for some diseases. Scientists
believe that certain diseases, like cystic fibrosis, are caused by
an error in a single gene. But genes alone rarely cause disease. Many
genetically complex disorders that affect millions of people—
for example, heart disease, depression, and cancer—
are caused by many different genes. Combinations of these genes, along
with how we live our lives— what we
eat, whether we exercise or smoke, and what we are exposed to in the
environment— cause these diseases.
Researchers do not yet know what most of these combinations of factors
are. To discover which genes contribute to complex diseases, scientists
must keep looking to find all of the gene differences that exist in
all people.
|
| Q: |
What's involved in this sort of genetics research
study? |
| A: |
Your body is made up of individual units
called cells. Your DNA (your personal genetic code) is tucked inside
each of your cells. If you agree to participate in a genetics research
study, scientists will collect a small sample of your cells in order
to read this code. One of the simplest ways to do this is to collect
a strand of hair or a sample of blood, or to gently rub the inside
of your cheek with a cotton swab. Scientists will study the DNA from
these samples and, through laboratory techniques, they will read the
spellings of your genes. |
| Q: |
Can researchers study my genome without my knowing
about it or giving my permission? |
| A: |
No. Researchers take great care with
DNA samples obtained from research volunteers. Before participating
in any research study, you are required by law to read and sign an
"informed consent" form. Before collecting samples of your
DNA, scientists must tell you the purpose of their study and also
if— and for how long—
your DNA sample will be stored in a facility called a "repository".
Researchers must also get your permission to permit your DNA sample
to be used by other scientists for future studies. |
| Q: |
What are the benefits of genetics research to the
groups and populations whose members volunteer to participate? |
| A: |
Studying genes from people who are members of a given
population or group— sometimes called
a "community"— can be a good
thing for that community as a whole. Research results could ultimately
point to treatment or prevention strategies that benefit many people
in that community. |
| Q: |
What are the risks? |
| A: |
Research results could lead to the stereotyping of
a community as being more likely to have a certain disease. But this
may not be the case if the reason that the disease was found in a
group is that the group members were simply more willing to take part
in a genetics research study. |
| Q: |
How do researchers protect people who volunteer
to take part in genetics research? |
| A: |
Participating in any research study is voluntary,
and there are strong safeguards to protect medical research volunteers.
Scientists who conduct research with people are required to take important
precautions with human DNA samples—
for example, removing identifying information and not sharing the
samples with other researchers without receiving permission from you.
Before you agree to participate in a study, read about the study's
goals and ask the researchers what benefits and risks may result.
Take time to read and understand the informed consent document that
you are required by law to sign before participating in any research
study. Find out which members of your community were on the "Institutional
Review Board" that by law is required to review and approve all
federally funded human research studies. |
| Q: |
Are there other protections for the DNA samples
collected by researchers? |
| A: |
One example of other protections is found at the National
Institute of General Medical Sciences Human Genetic Cell Repository.
The National Institute of General Medical Sciences (a part of the
National Institutes of Health) provides funding and oversight to this
repository. Scientists can obtain samples from the repository to use
for their genetics research studies. Cells stored in the repository
are not identifiable by donor. When you agree to participate, scientists
should also provide you with information on how you can learn about
the results of research studies performed with your DNA sample. To
protect identified ethnic and racial communities, the National Institute
of General Medical Sciences requires that researchers who wish to
collect tissue samples from members of communities must first talk
to community members and community leaders. |
|
