All humans share 99.9% of the same DNA

The 4% DNA difference between humans and chimps

On the genetic level, we’re not all that different from chimps. But those small differences in DNA can have huge effects. This 11-minute video digs in to the topic.

Half of human DNA is inherited from each parent

Within most cells reside 23 pairs of chromosomes made of tightly wound DNA, and half of each pair is inherited from each parent. The 23rd pair consists of two X-shaped chromosomes, or one such chromosome paired with a Y chromosome, and determines biological sex.

Only 2% of human DNA codes for proteins

The entire human genome contains about 20,000 protein-coding genes, with the rest having initially been categorized as "junk" DNA. However, research since 2003 suggests that this "dark genome" regulates how protein-coding genes are expressed in response to environmental factors encountered by cells.

Genes are the basic units of heredity

These segments of DNA—long molecules made of nucleotides that coil into chromosomes—code instructions for making specific proteins, which correspond to different traits. Approximately 98 to 99% of human DNA is non-coding, with functions beyond protein synthesis.

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

Genetic testing examines gene variants to help explain disease symptoms. It explores how genetic differences between individuals can be used to understand risks of developing diseases like Huntington's Disease or passing variants linked to disease onto offspring.

Humans are more genetically similar to cats than to dogs

While humans are not closely related to either cats or dogs from an evolutionary standpoint, scientists find that human and cat chromosomes are organized more similarly to each other than human and dog chromosomes, making cats a better model for studying human diseases.

Why genetic similarities between humans suggest a past near-extinction event

Researchers have found that low genetic diversity among humans—even those on opposite sides of the planet—may result from a breeding population of as few as 1,280 adults, estimated to have existed 930,000 years ago. This genetic bottleneck may have resulted from a near-extinction or from a small population of human ancestors, from which we all descend, that broke off from a larger population.

You're probably 2% Neanderthal

Scientists examining the evolutionary history recorded within our DNA are uncovering the global human story in greater detail. Watch the film to discover what percent Neanderthal you may be.

Where are humans on the evolutionary tree?

This interactive tree-shaped map explores the evolutionary connections between more than two million species. According to this map, humans are on the same branch as great apes, tarsiers, and treeshrews. That branch then splits into even smaller branches, with humans appearing on the same twig-like branch as chimpanzees and bonobos.

About 70% of the Human Genome Project's reference genome came from one donor

Volunteers who donated blood to the Human Genome Project consented to using no more than 10% of their DNA, raising questions about the project's legality. Listen to how pressure from a private competitor may have driven officials to ignore ethical standards.

Up to 8% of the human genome consists of ancient viral DNA

Human endogenous retroviruses are remnants of infections that affected human primate ancestors millions of years ago and were passed on by infiltrating sperm and egg cells. Studies have shown that this DNA may play a role in immune responses and in placental formation.

Nineteen years after its conclusion, scientists finish what the HGP started

The Human Genome Project mapped 92% of the human genome sequence upon its completion in 2003, leaving unreachable DNA regions unmapped. PacBio HiFi DNA sequencing allowed its completion 19 years later, with the additional mapping of 200 million DNA letters.

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.

Explore different living beings' sizes, from DNA to whales and the Pando clone

The Pando is actually a single organism in Utah, comprising more than 47,000 stems connected by a vast root system. It spans roughly 108 acres. Meanwhile, the average human stands at 5 feet and 7 inches. DNA, the genetic instructions for life, stands at a height of 3.5 nanometers.

Studies suggest only 9% of a dog's personality comes from its breed

While all dogs descend from wolves domesticated and bred for specific tasks by humans at least 15,000 years ago, most behavioral characteristics result from a mix of genetics and environment, which result in diverse canine dispositions within the same breed.

South American lungfish has the largest animal genome, with 91 billion base pairs

This genome is 30 times larger than a human's due to significant amounts of "junk DNA" and jumping genes, or transposons. Transposons can jump or copy over to other parts of a genome and may aid adaptation.

The first criminal conviction through the use of DNA evidence was in 1988

Chromosomes contain markers where short DNA sequences repeat a variable number of times from person to person. A DNA profile is constructed by identifying the number of repeats across 20 regions throughout a genome, which can be compared against a database. DNA paternity tests work similarly by comparing markers between children and their fathers. (Some readers may experience a paywall.)

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.

Nitrogenous bases connect like puzzle pieces due to their shape

There are four bases—adenine, thymine, cytosine, and guanine—which keep the two strands of DNA connected via chemical bonds between them. Connections between thymine and adenine require two hydrogen bonds, while those between cytosine and guanine need three hydrogen bonds. These differences in bond number prevent non-complementary pairings.

Organisms can possess multiple unique sets of DNA in one body

Genetic chimeras can result when cells with different DNA combine, such as when two sperm cells fertilize two egg cells, creating two embryos that then merge. In mosaicism, mutations arise within an organism after conception and can spread through cell division, resulting in diseases and forming genetically distinct anatomy.

Like fingerprints, brain anatomy is unique too

Researchers have discovered that a combination of experiences and genetic factors shape the anatomy of the human brain. They found even quick experiences affect the brain’s genetic makeup, which—over time—means every person develops a completely unique brain anatomy. While brain imaging could be used to identify individuals, it remains much more expensive than fingerprinting for now. Read to found out more about this study from the University of Zurich.

The oldest DNA recovered so far is 2 million years old

The oldest DNA recovered so far is about 2 million years old and has given scientists an unadulterated peek into ancient history. This nine-minute video explores the findings and implications of the DNA, which was pulled from frozen soil in...

Genetics may account for nearly 67% of mosquito attractiveness

In a mosquito attraction study published in 2015, identical twins appeared equally attractive to mosquitoes in lab tests, whereas some nonidentical twins were far less likely to be bitten than their siblings. Other work related showed that body odor is also more similar between identical twins.

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.

More than 90% of the atoms in the human body were forged by stars

Excluding all of the universe's hydrogen and most of its helium and lithium that formed in the Big Bang, elements found in significant amounts in our bodies formed through nuclear fusion within stars, collisions between neutron stars, or stars undergoing supernova. For example, all of the oxygen (65% of our mass) came from massive stars exploding.

Nearly 99% of the Smithsonian's specimens are hidden in high-security

At the National Museum of Natural History, nearly 99% of its 147 million specimens are stored in secure research collections rather than on display, where they are actively used for scientific work ranging from tracking invasive species to improving aviation safety.

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.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

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

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

Three Ebola species are responsible for most large outbreaks of the disease, yet the only approved Ebola vaccine is known to work against just one of them.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

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.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

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.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

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

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

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

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

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.

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

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

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.

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.