Around 5 million of our 3 billion DNA letters differ between individuals

Ancestry testing matches DNA to known genetic variants found in specific ancestries

After a lab receives a person's sample, the DNA is separated into single strands, which are chemically cut into smaller fragments. The fragments are then fed into an array of variants of known origins, and technicians observe if a person's fragments bind to specific variants.

DNA carries the unique instructions that shape how each person grows and functions

The human genome contains over six billion DNA letters, organized into 46 chromosomes inherited from both parents. Genes—sections of DNA—serve as templates for making proteins, and variations in these sequences can affect how our bodies work or respond to the environment.

Changing a single letter in DNA can permanently alter an organism

Genetic mutations occur when cells replicate, which requires a copy of DNA to be created, and involve substituting, deleting, or inserting letters in a cell's genetic code. Mutations can be caused by normal cellular processes, chemical exposure (e.g., carcinogens), or radiation and may result in genetic disorders or genetic variations that drive evolution.

All humans share 99.9% of the same DNA

Of the 3 billion base pairs that make up the human genome—the complete set of genetic material for the species—the diversity of humans is the result of variations in about 3 million molecular bases. The closest nonhuman genetic match is the chimp, with 98.8% similar genetics.

Genetic drug matching, called pharmacogenomics, can help avoid dangerous drug reactions

Certain gene variants can affect how quickly or slowly medications are broken down in the body, affecting drug effectiveness and the risk of drugs failing. Such testing is often not covered by insurance companies though research indicates if these tests were performed for more than six drugs across the US population, avoided ailments would likely climb into the hundreds of thousands. (Some users may encounter a paywall.)

Here’s how different genetic disorders get passed on

The human genome is complex, as identified by the Human Genome Project. This article digs in to genetic disorders, the most common ones, and how they are diagnosed.

Why your dog’s DNA isn’t destiny

DNA tests tell people about their pet’s breed and attempt to predict things about its behavior and health. But for all that these tests might provide some interesting results, they need to be taken with caution. Here's a look at what we can and can't learn from our pets' DNA.

Scientists identify hundreds of genes responsible for OCD

Researchers analyzed the DNA of more than 53,000 people with OCD and identified 30 areas in the genome linked to the disease, containing 249 genes of interest. Of those, several were linked to other brain disorders, paving the way for genetic treatments of various mental illnesses.

The lack of diversity in DNA databases limits their applications

European ancestry dominates genetic research, hindering the usage of genetic databases for precision medicine for other groups, including African Americans, who face higher health risks due to genetic variants. Many Indigenous communities have also resisted genetic research due to past exploitation. (Some readers may experience a paywall.)

US regulators have approved an at-home genetic test looking for BRCA gene mutations

The direct-to-consumer genetic test, approved by US regulators in 2018, examines 3 out of the more than 1,000 known breast cancer-linked genetic mutations. It looks for genetic variations that can increase risk for breast, ovarian, and other cancers. These mutations are most commonly found among Jewish people with Eastern European ancestry.

Polygenic scores aim to predict traits based on the contributions of many genes

These novel tests for multifactorial conditions evaluate the probability of traits like elevated blood pressure, diabetes, or high cholesterol based on what researchers currently know about different gene variants and their links to various traits. The tests are predictive, not definitive, partly because environmental factors influence the expression of genes. What's more, knowledge about cumulative effects from individual genes continues to evolve. The American Society for Reproductive Medicine states that these tests are too unreliable and nascent for clinical use.

Explore the differences between healthy and cancerous cells using a DNA microarray

In this simulation, you will learn how scientists use microarrays to experiment on thousands of genes at the same time. By determining which genes are on or off, users can identify those that contribute to cancer formation.

Modern genetic testing stems from a 1950s discovery about the cause of Down syndrome

Scientists found that an additional copy of chromosome 21 causes the disease and developed an approach to stain chromosomes so they could be manually sorted and counted, which is called karyotyping. The breakthrough discovery by Marthe Gautier, a young French doctor and cytogenetics researcher, was appropriated by a male colleague, who listed himself as the lead author of the study reporting the finding.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

The Golden State killer case spotlights how genetic testing can affect your—and your relatives'—privacy

Police managed to use consumer DNA test results to close a case 32 years after a killer was believed to have committed at least 12 murders and 50 rapes. Their "smoking gun": They compared a DNA sample from the crime scene to genetic data relatives had shared on an open-source genealogy database. The suspect was caught after investigators explored family trees on this database and connected the dots from over 100 distant relatives who had some percentage of DNA that matched the killer. (Some users may encounter a paywall.)

Despite privacy risks, scientists are using DNA in the air to assess ecosystem health

While DNA in soil and water samples has long been used for such analyses, airborne DNA is being incorporated into such efforts to monitor individual species abundance, detect invasive species, measure biodiversity, and determine the success of conservation actions. Future work may include detecting attacks from biological weapons.

Explore the original goals of the Human Genome Project

The project goals emphasized DNA sequencing technologies and methods, which would lead to future treatments of genetic disorders. Exploring the project data's ethical and social implications was also considered.

Carrier screening enables individuals without symptoms to see if they carry a gene for disease

Some conditions are autosomal recessive—meaning a person may carry a gene for that condition, but not have symptoms. Cystic fibrosis, sickle cell disease, and Tay-Sachs disease are examples of autosomal recessive diseases in which a person must inherit two copies of a nonfunctioning gene—one from each parent—to develop disease.

All publicly available DNA sequences are available at GenBank

The National Institutes of Health's database stores comprehensive, annotated DNA sequences as part of the International Nucleotide Sequence Database Collaboration. It encourages unrestricted data access within the scientific community while allowing submitters to retain intellectual property rights over their data.

The structure of DNA helices comes in three major varieties

The hereditary molecule can take the form of A-DNA, B-DNA, or Z-DNA based on environmental conditions such as ion concentration and humidity—a characteristic identified by Rosalind Franklin. A-DNA is the shortest and widest of the three, while Z-DNA is the longest and narrowest. B-DNA—the most common variety in living cells—is the intermediate.

Visualization of printing synthetic DNA

Ever wonder how synthetic DNA is made? Discover how GenScript uses innovative technology to synthesize precise, high-quality DNA at a larger scale than ever before.

Biological aging tests assess the breakdown of physiological systems

Known as aging clocks, these tests compare various metrics, like DNA methylation patterns and protein profiles, to healthy baselines. However, the non-uniformity of these baselines across individuals limits testing accuracy and prevents their clinical use.

Twin studies helped scientists understand why mosquitoes like some of us more than others

A combination of carbon dioxide output, skin chemistry, genetic factors, hormones, and clothing choice can make us particularly vulnerable to mosquito bites. Watch how mosquitoes responded to one man in the video versus his wife, a research approach typically conducted with identical and fraternal twins to test mosquito attractiveness.

Your DNA may determine whether you like coffee or tea

Whether people prefer coffee or tea may boil down to a matter of taste genetics. People with a version of a gene that increases sensitivity to the bitter flavor of caffeine tend to be coffee drinkers, according to a report. Read on for more.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Everything scientists could learn by looking at your skull

Our skulls are all unique, but they also share characteristics across groups of people. In the absence of fingerprints, forensic scientists can learn a lot about you just from your skull.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

The 2026 Ebola outbreak is hampered by a lack of vaccine against the species of the virus, heightening the need for rapid tests to aid in disease control.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

Meet the 56 signers of the Declaration of Independence—most of whom didn't put pen to paper until August 2, 1776—and see their original signatures.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Calculate how much of your tax dollars go to each federal program based on your income, filing status, and number of children

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.