Deep red garnets are found all over the world, from Thailand and Sri Lanka to the Adirondacks.
The stones that make their way into rings and necklaces must have a flawless interior. But sometimes garnets are marred with intricate traceries of microscopic tunnels.
Magnus Ivarsson, a geobiologist at the Swedish Museum of Natural History, and his colleagues found evidence that contradicted standard geological explanations for how the cavities might be formed. In a paper in PLOS One, the researchers are floating a new hypothesis: Perhaps what's making the tunnels is alive.
The mineral doing the tunneling must be harder than the surrounding substance, and garnets happen to be very, very hard.
When the researchers cracked the garnets open, they tested the insides of the tunnels and found signs of fatty acids and other lipids, potential indicators of life.
The researchers' best guess goes like this: Normal wear-and-tear on the surface of a garnet creates divots. Microorganisms, probably fungi, can colonize these hollows. Then, if the stone is the best nearby source for certain nutrients, such as iron, perhaps they use an as-yet mysterious chemical reaction to burrow deeper, harvesting sustenance as they go.
Zombie gene may protect elephants from cancer
Maybe it's the elephant's genes that never forget.
In addition to having great memories, elephants are known for having a very low incidence of cancer. Research has uncovered a surprising factor that protects elephants against the disease: a gene that had gone dormant in their ancestors, but got turned back on as their bodies grew ever bigger.
Scientists call it a "zombie gene" — "a reanimated pseudogene that kills cells when expressed."
By understanding how those species have evolved to ward off malignancies could, in time, help biologists find ways to drive down human vulnerability to cancer.
Lynch's team went looking for LIF (short for Leukemia Inhibiting Factor) genes in 53 mammals.
In most species, they found a single active LIF gene. But in the modern African elephant — as well as in the manatee and the rock hyrax, distant cousins — they found seven to 11 additional copies of the LIF gene, called pseudogenes. In every species but the elephant, these LIF genes and their extra duplicates were inactive.
But in the elephant, the team saw that one of the additional copies of the LIF gene was active. When the researchers induced cell stress, a widely recognized tumor-suppressor mechanism turned on. That, in turn, activated the LIF6 pseudogene.
Stirred to life, the zombie gene proceeded to carry out its grim program, entering the internal machinery of damaged cells and ordering them to kill themselves. In elephant tissue, the damaged cells turned themselves inside-out, and cancer was thwarted before it could gain any momentum.
And when the researchers suppressed the action of the LIF6 "zombie gene," they found that stressed cells were more likely to form tumors in elephant tissue.
