Y Chromosome Loss Becomes Common in Men With Age
By age 70, about 35% of men have lost the Y chromosome from some blood cells, with affected cells ranging from roughly 4% to 70%.
Details
As men age, some blood cells can lose their Y chromosome. This is called mosaic loss of chromosome Y, or mLOY, because the change affects only a portion of cells rather than every cell in the body. Large genetic studies have found that mLOY becomes much more common with age and is detectable in more than 30% of men over 70. The amount of affected blood cells can vary widely between individuals. A 2025 study using whole genome sequencing from more than 25,000 genetically diverse male participants found mLOY in 11.5% of the overall study population, with the frequency rising sharply with age. The researchers also found genetic factors associated with susceptibility to mLOY and showed that some Y chromosome variants are more likely to be lost than others. Earlier research has associated mosaic Y loss in blood with several age related conditions, including cancer, cardiovascular disease, Alzheimer disease, and shorter survival. These are associations in much of the human evidence, and the biological reasons for the links are still being investigated. Importantly, this does not mean that an older man suddenly loses the Y chromosome from his entire body. It is primarily a mosaic change in certain cell populations, especially blood cells, while other cells can retain the chromosome.
More videos
- Why Spider Legs Work Like Tiny Hydraulic Systems
Spiders lack extensor muscles in their major leg joints, so they use blood-like fluid pressure to extend their legs, which curl when that pressure stops.
Tags: Medicine
- Turtles Have Been Around for More Than 200 Million Years
Some of the oldest known turtle fossils date to about 215 million years ago, showing turtles were already around during the Triassic Period.
Tags: Medicine
- Why Crows Cover Themselves in Ants
Crows and many other birds deliberately cover their feathers with ants, a behavior called anting, but scientists still do not know exactly why.
Tags: Medicine
- Scientists Identify About 18,000 New Species Every Year
Scientists identify about 18,000 new species each year, revealing how much of Earth life is still unknown to science.
Tags: Medicine
- Lungfish Are Closer to Humans Than Most Fish
Lungfish are more closely related to humans and other land vertebrates than they are to most familiar fish like salmon and tuna.
Tags: Medicine
- Some Sea Stars Can Regrow an Entire Body From One Arm
Some sea stars can regrow an entire body from a single arm, and one species can split into two males that later become females as they grow.
Tags: Medicine
- Your Body Has More Bacterial Cells Than Human Cells
Your body has roughly 30 trillion human cells and 38 trillion bacteria, so bacteria slightly outnumber human cells, with most concentrated in the gut.
Tags: Medicine
- Sleep Helps Flush Waste From the Brain
In mice, sleep expands the space between brain cells, helping cerebrospinal fluid wash away waste, including proteins linked to Alzheimer’s disease.
Tags: Medicine
- Humans Are Still Evolving, and It Shows in Surprising Traits
Humans are still evolving, with recent genetic adaptations linked to free-diving, high-altitude living, disease resistance, and digesting milk as adults.
Tags: Medicine
- These Ants Rescue Their Wounded After Termite Battles
Megaponera analis ants rescue injured nestmates after termite battles, carrying them home so they can recover and return to future raids.
Tags: Medicine
- The Tiny Ear Muscle Some People Can Flex on Command
Some people can voluntarily flex a tiny middle-ear muscle called the tensor tympani and hear a low rumbling sound that only they can hear.
Tags: Medicine
