Frequently Asked Questions

Humans share 99.9% of our DNA with each other. That means that only 0.1% of your DNA is different from a complete stranger! However, when people are closely related, they share even more of their DNA with each other than the 99.9%. For example, identical twins share all of their DNA with each other. If the DNA of two unrelated people is compared, you would expect that the 0.1% of DNA that is unique to each of them would be very different. However, people who are closely related, for example mother and child, would share about half of that 0.1% of their DNA with each other. In other words, the DNA of a mother and her child is much more the same than the DNA of people who are not related to each other. You also share more DNA with your more distant relatives than with people you aren’t related to, but as relatives get further away in the family tree, you share less and less DNA with them.

 Paternity testing looks at the DNA of two people (often a father and a child) to determine how much of their DNA is the same and how much is different. If the two people share more DNA with each other than would be expected, the test will be positive: they are highly likely to be father and son. This type of test is over 99.9% accurate and it is extremely unlikely that unrelated people would share enough DNA to cause the test to be falsely positive. DNA paternity testing is so highly accurate because the variations in human DNA are very diverse among people that are not related but are very similar among people who are related. Paternity testing is different than other types of genetic testing in that it is only looking at common variations in the DNA that don’t cause diseases. This means that paternity testing cannot be used to diagnose or predict if someone is going to get a disease.

There are many genetic test kits that are currently available that claim to give you information about your health. These genetic tests are offered directly to the consumer (you) without being ordered by a physician or genetic counselor. These tests that can be taken at home are often offered at a relatively low price and can be attractive due to their claims of predicting your genetic destiny. They often claim to give you predictions about your risk for complex diseases such as heart disease, diabetes or osteoporosis. There are even others that suggest the type of diet that would best suit your genetic makeup or the type of exercise that would be most beneficial for you based on your genes. Learn more about the complex diseases some tests may look at: Complex Disease

The fact that a doctor doesn’t order it doesn’t mean that the information given by these do-it-yourself genetic tests is necessarily bad or wrong. But it does mean that a person should take caution about how they use the information they get from them. The problem with these genetic tests is that we do not yet know enough about all of the genes involved in causing complex diseases to make recommendations based on the results of the test. Some results may be based on relatively few genes or weak associations with many different genes. Because of this, a person’s genetic test may say that they have a low risk for a disease based on the finding of a single gene variation, when in reality they have several other variations (that weren’t tested for) in other genes that actually increase their risk for the disease. This may falsely reassure someone that they are at lower risk for the disease than they truly are.

Another major issue with genetic testing that isn’t ordered by a physician is that there is little or no genetic counseling associated with ordering the test or receiving the results. When a genetic test is ordered through a physician, genetic counseling is typically offered, which allows a patient to ask questions and gain information about the implications of the test, how they can use the information, and if they are emotionally ready for the information. Some of these tests can identify mutations that have significant health implications. It may be psychologically upsetting for someone to learn they are at risk for a specific disease for which there is little that can be done to prevent or treat. The bottom line for these at-home genetic tests is that the results may be interesting and possibly helpful in the future, but your family health history is still the best indicator of your risk for complex diseases such as heart disease, diabetes, and cancer!

Scientists have not cloned humans! Only some animals have been cloned including a cat, dog, pig and most famously Dolly the sheep. Most scientists and credible scientific associations consider human cloning to be dangerous, wrought with ethical problems and not a good use of genetic technology, funding and resources.

The American Medical Association as well as other well known scientific groups have advised that scientists not attempt to clone humans. Much of this is due to what was learned during the attempts to clone animal species. Many of the animals that were cloned did not survive the process or had severe health conditions. Since these same problems would likely happen with attempts to clone humans, scientists and law makers believe the risks associated with cloning are too high. To learn more about the ethical issues associated with human cloning visit the Human Genome Project Cloning Fact Sheet.

“Designer babies” is a term used to describe the idea of creating babies through genetic technology to look a certain way or have certain abilities. For example, a couple may desire to have a child who has green eyes and has amazing running abilities. Even though the technology to create designer babies may one day be available, making designer babies a reality is not the goal of scientific research! Most researchers feel that creating “designer babies” is not an appropriate use of genetic technology and resources. It is thought that since this type of technology ultimately will not benefit human health and well being, scientific efforts should not be focused in this area.

As you can learn in our What is Genetic Research page, the goal of genetics research is to find the genetic causes of disease so that disease can be prevented and healthcare services are improved.

The vast majority of our DNA code is identical to each other. In fact, only about 0.1% of our DNA differs from person to person! It is this 0.1% that makes each of us different and unique. These differences are what make us look different (i.e. height, hair color, and eye color), and also are what may put people at risk for certain disease. Because of this, some genetic conditions are found more often in people of a specific group. Most of these conditions are recessive conditions. This means that both parents, mom and dad, must be carriers of a mutation in the same gene for them to have a child with the condition. Carriers typically don’t have symptoms of the disease. In fact, most people don’t know they are carriers for one of these conditions until they have a child with the condition or they have carrier testing.

For example, people of Northern European background (Caucasians) have a higher chance than people of other ethnicities of having a child with a disease called cystic fibrosis (CF), a severe disease that affects the lungs, pancreas and digestive system. This is because about 1 out of 29 people of Northern European descent is a carrier for CF. Another example is sickle cell anemia, which is a blood disease most common in people of African descent. About 1 out of 10 African-Americans are carriers of sickle cell anemia and often are said to have sickle cell trait. There are many other conditions that are more common in specific ethnic groups including Tay Sachs disease in the Ashkenazi Jewish population and thalassemias in people of Mediterranean descent. Genetic counseling and carrier testing are routinely offered for families who are planning a pregnancy or for women who are pregnant to see if their child is at risk for these types of genetic conditions. If you would like to find a genetic counselor in your area, please go to the National Society of Genetic Counselors, or NSGC website.

Nearly all diseases are cause by a combination of both genes and environment. Genetic research has lead to the discovery of many genes that contribute to a person’s risk for getting diseases like Alzheimer disease, diabetes, autism, cancer, and heart disease. However, the genes aren’t the whole story! It also has been discovered that a person’s environment such as their diet, how much they exercise, stress level, and habits also contribute to these diseases. Because of the interaction of all these factors, these diseases are often called complex diseases. While complex diseases can run in a family, they may not follow a particular pattern. For example, there may be a gene that is being passed through a family that causes a high risk for heart disease. This gene only increases a person’s chance of getting heart disease, but does not necessarily cause the disease. This means that even if a person inherits this “risky” gene, they may not develop heart disease, especially if they follow a healthy diet and exercise regularly.

Complex diseases can be hard to understand and predict. It can be helpful to know if someone has genetic risk factors for a complex disease so that the person can change their lifestyle. For example, a person who has is at high risk for diabetes may be advised by their doctor to change their diet, monitor their blood sugar, or exercise regularly. This may help to prevent that person from developing diabetes, even though they are predisposed to the disease. One way to find out if someone is at high risk for a complex disease is to look at their family health history. Learn more by visiting Complex Disease.

Genetic testing is a test that looks at our DNA. It has many uses outside of how it is used in movies and on TV! Doctors use genetic testing to diagnose disease, predict if a person is at risk for disease, or find out if a person is a carrier of a genetic condition. The type of doctor that typically orders genetic testing is a geneticist, but other doctors such as OB/GYNs, family practice doctors, or other specialists may order DNA testing. It is very helpful to find out if a disease has a genetic basis through genetic testing so that a correct diagnosis can be made or people in the family are aware of their risk for disease. Mutations that cause a genetic disease can run in a family, so genetic testing of one family member can allow others in the family to be tested for that same mutation. This knowledge may allow others in a family to prevent or better treat the disease.

There are many types of genetic tests that a geneticist may order. One common genetic test is called a karyotype. A karyotype is a blood test that looks at the structure of a person’s chromosomes, which are the packages of our DNA found in every cell of the body. A change in the amount or number of chromosomes can cause problems with growth and development. For example, Down syndrome is caused by an extra chromosome #21. A karyotype is often ordered if a child or adult is having problems with development, infertility, mental retardation or has specific physical features. Also, a karyotype can be done during pregnancy through a procedure called amniocentesis to diagnose chromosome abnormalities such as Down syndrome. A microarray is another type of genetic test that looks at the chromosomes, but is much more detailed. Other genetic tests can look closer at the DNA, into the genes, to see if a person has a mutation in a specific gene that is causing a disease. To learn more about genetic testing visit: What is Genetic Testing?

When you participate in genetic research at the Hussman Institute for Human Genomics (HIHG), your personal health and family information is kept confidential. We do not allow non-researchers or people outside of the HIHG to look at or use the information that is collected for the research study. We would need your permission before we could use your information for any other purpose. Your DNA that is used for research will not be used to identify you for criminal activity or for paternity testing. Any time you are involved in research at any institution, you should be explained your rights as a participant and how your information will be kept private and confidential.

To read more about the protections for research participants, visit: US Department of Health and Human Services

Scientists have successfully cloned several animals including a cat, dog, pig, and most famously Dolly the sheep. Rainbow was the original cat that was cloned. Her clone, Copy Cat, was born on December 22, 2001. She was the first cloned pet. Cloning was done by taking Rainbow’s DNA and putting inside an embryo that had all its own DNA removed. This embryo was then put inside another cat who carried the pregnancy and gave birth to Copy Cat. Copy Cat is healthy and has even had her own litter of kittens!

An interesting detail is that Copy Cat doesn’t look exactly like her clone Rainbow. Even though clones have the exact same DNA, they don’t always look exactly the same! This is because of complex changes to DNA that can happen before birth caused by the surroundings or by the environment that the embryo is in. Copy Cat was born and grew up in a completely different environment than Rainbow, which has effected the way she looks and acts. To learn more about cloning, please visit The University of Utah Genetic Learning Center: Cloning.

It is true that identical twins share their DNA code with each other. This is because identical twins were formed from the exact same sperm and egg from their father and mother. (In contrast, fraternal twins are formed from two different sperm and two different eggs.) Usually, the egg and sperm come together and create an embryo, which eventually grows into a human baby. However, in the case of identical twins, early in development, this embryo divides into two. This creates two babies rather than one.

While the two babies share the same DNA code, there is more to our genetics than just that. During development in the womb and after birth, our surroundings, exposures, and nutrition influence how our genes are expressed and how our bodies and minds develop. For example, two identical twins may have the same genes for height, but if one twin does not receive the same amount of nutrients while in the womb, it may be shorter than the other twin. We know also, that there are some changes to our genes that can happen during the embryonic period or during development. While this rarely happens, it makes it so that one identical twin may have a genetic condition, while the other twin does not. Our genetic code is a very large part of our genetic makeup, but there are other factors, genetic and environmental, that make us unique!

Any couple related or not, also is at risk of having a child with genetic conditions or health problems! Although taboo in some cultures, marriage between first cousins is accepted in many cultures around the world. The vast majority of children of first cousins are healthy and do not have problems due to their parents’ relatedness. It is important to keep in mind that even for an unrelated couple, there is an approximately 2-3% chance that their child is born with a birth defect, genetic syndrome, or disability.

The risk for children of first cousins is increased over this background, by about 3%. The risk for genetic conditions and health problems does increase as the relatedness of parents increases. For example, marriages between brothers and sisters are not typically culturally accepted. This is likely due to the dramatic increase in birth defects, genetic conditions and health problems seen in children of these matings.

Thanks to recently developed legislation, many fears can be reduced about the use of genetic information for insurance or employment eligibility. A new legislative act called the Genetic Information Non-Discrimination Act (GINA), aims to protect your genetic information from such misuse. The Act prohibits the use of genetic information including family health history to determine a person’s premiums or eligibility for individual plan or group health insurance. The new protections also prohibit the use of genetic information, including family health history, by employers in decisions such as hiring, firing, or promotions. Additionally, the Act makes it illegal for employers or health insurance companies to require a person or their family members to have a genetic test to determine their eligibility. Tests covered by the new legislation are predictive tests, meaning those genetic tests that determine a person’s risk of developing a specific disease, not those that diagnose a genetic disease in a person with symptoms. Often, people who get this testing are at increased risk of having a genetic change that causes the disease due to their family history or ethnicity. Examples of genetic tests covered by the Act include the following: Carrier screening for recessive conditions such as cystic fibrosis (CF); Tay-Sachs or sickle cell anemia; predictive BRCA1/2 testing or hereditary forms of colon cancer; testing of cancer tumors for management decisions; and predictive testing for adult onset diseases (Huntington disease).

The Genetic Information Non-Discrimination Act also has limitations to its protection. It does not prevent insurance or employment discrimination based on a current or diagnosed condition, even if it is genetic. For example, if a woman who has breast cancer has a genetic test that reveal she has had a genetic change that caused the breast cancer, the woman’s test result is treated as any other medical test result, and does not fall under the new special protections. Insurance companies can use the diagnosis of breast cancer in decisions about rates and eligibility. This is different than someone who has a genetic test that reveals they have a very high risk for breast cancer, but the person does not yet have breast cancer (a predictive test); the Act protects that information from being used in employment or insurance decisions. Also the new protections do not apply to life insurance, disability insurance or long-term care insurance. Members of the military are not covered by the Act, as well as employees of businesses that have less than 15 employees.

If you want to learn more about the coverage and limitations of the Genetic Information Non-Discrimination Act, please visit the Genetics & Public Policy Center.