DNA: The Genetic Lottery
Mar 01, 2018 08:30AM
● By Jason Huddle
DNA: The Genetic Lottery
Besides serving as a tool for those wanting to reunite with biological family members, genetic testing also plays a role in the medical and law enforcement fields.
Last July, 23andMe – a consumer genetics and research company based in California – conducted a survey of 1,000 Americans aged 18 and older. Questions surrounding their knowledge, curiosity and expectations about DNA were asked.
“Genetic testing can be an engaging tool for people to learn more about their health and ancestry. At the same time, it can help people learn about genetics in general – something that is increasingly important as genetic information becomes more accessible,” Thao Do, PhD, 23andMe education and academia program manager, says.
That’s because the survey indicated that many Americans aren’t knowledgeable about DNA or how it’s constructed. Forty percent of respondents didn’t know that DNA is organized in chromosomes; 75 percent didn’t know that we each have 23 pair of chromosomes; and 83 percent didn’t know that we all share about 99.5 percent of our DNA with each other.
While deoxyribonucleic acid – or DNA –was discovered in 1869, its actual structure wasn’t unearthed until 1953 when British scientists Rosalind Franklin and Maurice Wilkins studied DNA by way of x-rays. Franklin had taken an x-ray photograph that was then used by researchers James Watson and Francis Crick to determine the three-dimensional shape of DNA –a double helix with the two strands connected by hydrogen bonds.
“The DNA molecule, present in every cell in our bodies, is a chain of molecules, sugars and phosphates. The order in which these components arrange themselves in the chain is, statistically speaking, unique to every individual (except for identical twins),” lawyers.com explains. “The DNA molecule is the same in every cell, and remains constant (with slight, rare variations) during an individual’s life.”
Inherited Medical Conditions
The National Human Genome Research Institute identifies the various types of genetic testing and what they can mean for those seeking answers.
“Diagnostic testing is used to precisely identify the disease that is making a person ill. The results of a diagnostic test may help you make choices about how to treat or manage your health.
“Predictive and pre-symptomatic genetic tests are used to find gene changes that increase a person’s likelihood of developing diseases. The results of these tests provide you with information about your risk of developing a specific disease. Such information may be useful in decisions about your lifestyle and healthcare.
“Carrier testing is used to find people who ‘carry’ a change in a gene that is linked to disease. Carriers may show no signs of the disease; however, they have the ability to pass on the gene change to their children, who may develop the disease or become carriers themselves. Some diseases require a gene change to be inherited from both parents for the disease to occur. This type of testing usually is offered to people who have a family history of a specific inherited disease or who belong to certain ethnic groups that have a higher risk of specific inherited diseases.
“Prenatal testing is offered during pregnancy to help identify fetuses that have certain diseases. Newborn screening is used to test babies one or two days after birth to find out if they have certain diseases known to cause problems with health and development.
“Pharmacogenomic testing gives information about how certain medicines are processed by an individual’s body. This type of testing can help your healthcare provider choose the medicines that work best with your genetic makeup.
“Research genetic testing is used to learn more about the contributions of genes to health and to disease. Sometimes the results may not be directly helpful to participants, but they may benefit others by helping researchers expand their understanding of the human body, health and disease.”
23andMe says its survey showed about two-thirds of Americans would be more apt to take a DNA test if they knew their data could be used in genetic research, treatments and cures. This further breaks down into age groups, with 26 percent of millennials more likely to get a DNA test than older generations. This is likely due, in part, to the technology being so new.
“About 73 percent of individuals surveyed said that they were more likely to do a DNA test if they could learn about potential health risks. And that interest doesn’t change even if they were to learn about a risk for a condition that currently has no cure (78 percent),” according to the survey. “Asked if they would want to know about risks for serious conditions – such as late-onset Alzheimer’s disease, Parkinson’s disease or breast cancer – a majority of respondents (78 percent) said yes.”
Ninety percent of those questioned were familiar with the fact that they could learn about their ancestry through DNA testing, but 52 percent indicated that cost was the key factor stopping them. DNA tests can run from $100 to $2,000-plus; medical insurance may cover at least a portion.
Another concern – from 17 percent of respondents – was the privacy of their genetic testing data. It’s recommended that the provider’s Privacy Statement be read before committing to a particular DNA home test.
So, while 94 percent said they have the right to know their genetic make-up, only 8 percent have taken an at-home test.
There is a host of reasons why people might get medical genetic testing. Doctors may suggest it if families are known to exhibit a certain disease pattern. A genetic counselor can help them determine the pros and cons, and there are both.
The most obvious benefit is obtaining an answer. There’s comfort in finding out there is no mutation, but there’s also a sort of comfort in knowing steps can be taken in monitoring or combatting a disease. These can include diet and screenings. For instance, the chances of developing cardiovascular disease can be decreased by eating healthy, exercising and not smoking.
It’s also an emotional process. Testing positive for a particular mutation doesn’t always mean you develop the disease, but the anxiety that goes with the results can be difficult to handle.
DNA Testing and the Law
On about any given day, a news story breaks with DNA solving a criminal case, but it was originally used to determine paternity. Then, in 1986, British molecular biologist, Alec Jeffreys, used forensic DNA to clear a 17-year-old boy who’d confessed to two rape-murders. The actual killer was caught, also with DNA evidence.
In the U.S. the following year, Tommy Lee Andrews was convicted of rape in Florida when his DNA matched evidence found on the victim.
Just a few years later, the federal government initiated the Combined DNA Index System (CODIS). These national, state and local DNA databases serve as storage and sharing of DNA profiles, and are available to law enforcement agencies across the U.S.
To aid in building the profiles, the Department of Justice (DOJ) says, “States began passing laws requiring offenders convicted of certain offenses to provide DNA samples. Currently, all 50 states and the federal government have laws requiring that DNA samples be collected from some categories of offenders.
“The past decade has seen great advances in a powerful criminal justice tool. DNA can be used to identify criminals with incredible accuracy when biological evidence exists,” the DOJ adds. “By the same token, DNA can be used to clear suspects and exonerate persons mistakenly accused or convicted of crimes. In all, DNA technology is increasingly vital to ensuring accuracy and fairness in the criminal justice system.”
There are two ways to utilize DNA in a criminal investigation. One is where a DNA sample can be taken from a person of interest and used in comparison with DNA from other areas of the crime scene. A person’s DNA can be identified with tissue, blood, sweat, semen, bone, saliva, etc.
Lawyers.com says that each sample must be intact and large enough to analyze: a quarter-sized bloodstain or a dime-sized semen stain. “Then, each sample’s band pattern (its sequence) is compared to the other. If the bands match, scientists consult a national database of band patterns and determine the statistical chances that the match is a coincidence,” the site explains.
“In cases where a suspect has not yet been identified, biological evidence from the crime scene can be analyzed and compared to offender profiles in DNA databases to help identify the perpetrator. Crime scene evidence can also be linked to other crime scenes through the use of DNA databases,” the DOJ says.
As researchers continue to study DNA’s unique qualities, its feasible benefits in battling diseases like cancer and its ability to solve cold cases, there is no limit to its value.
Article by: Kim Cassell