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Human genome

The human genome is the genome of Homo sapiens. It is made up of 23 chromosome pairs with a total of about 3 billion DNA base pairs. There are 24 distinct human chromosomes: 22 autosomal chromosomes, plus the sex-determining X and Y chromosomes. Chromosomes 1-22 are numbered roughly in order of decreasing size. Somatic cells usually have one copy of chromosomes 1-22 from each parent, plus an X chromosome from the mother, and either an X or Y chromosome from the father, for a total of 46. There are an estimated 20,000-25,000 human protein-coding genes. The estimate of the number of human genes has been repeatedly revised down from initial predictions of 100,000 or more as genome sequence quality and gene finding methods have improved, and could continue to drop further.

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Health & Medicine News

February 7, 2026

New simulations reveal that both H1N1 and COVID-19 spread across U.S. cities in a matter of weeks, often before officials realized what was happening. Major travel hubs helped drive rapid nationwide transmission, with air travel playing a bigger ...
A major study suggests menopause is linked to changes in brain structure, mental health, and sleep. Brain scans revealed grey matter loss in areas tied to memory and emotional regulation, while many women reported increased anxiety, depression, and ...
For decades, Americans were surrounded by lead from car exhaust, factories, paint, and even drinking water, often without realizing the damage it caused. By analyzing hair samples preserved across generations, scientists uncovered a striking record ...
New research suggests that Epstein-Barr virus may actively provoke the immune system in people with multiple sclerosis. Scientists found large buildups of virus-targeting immune cells in the nervous ...
Researchers have discovered a previously unknown enzyme that plays a crucial role in fat production. By blocking it, they stopped weight gain, reduced liver damage, and lowered harmful cholesterol levels in animal studies. The finding opens the door ...
Colorectal cancer has long baffled scientists because, unlike most tumors, patients often do better when their cancers are packed with immune-suppressing regulatory T cells. New research finally explains why. Scientists discovered that these T cells ...
Scientists at Keck Medicine of USC are testing an experimental stem cell therapy that aims to restore the brain’s ability to produce dopamine, the chemical whose loss drives Parkinson’s disease. The early-stage clinical trial involves implanting ...
New research using rhesus monkeys suggests that the brain’s relationship with alcohol may begin forming long before a person ever takes a drink. Scientists found that exposure to alcohol before birth reshaped the brain’s dopamine system, a key ...
Scientists in Australia have uncovered a clever new way to fight some of the most dangerous drug-resistant bacteria by targeting a sugar that exists only on bacterial cells. By designing antibodies that recognize this unique sugar, researchers were ...
A new imaging breakthrough combines ultrasound and light-based techniques to generate vivid 3D images that show both tissue structure and blood vessel activity. Developed by researchers at Caltech and USC, the system delivers detailed results ...
Researchers have figured out how psoriasis can quietly turn into joint disease for some patients. Immune cells formed in inflamed skin can travel through the blood and reach the joints, where they sometimes trigger inflammation. The key difference ...
People who switch to a fully unprocessed diet don’t just eat differently—they eat smarter. Research from the University of Bristol shows that when people avoid ultra-processed foods, they naturally pile their plates with fruits and vegetables, ...

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