If you want to be leggier, consider moving to Florida. It might even work if your parents have average-sized limbs. New research has found that DNA isn’t the only route to long legs: Warmer temperatures can also lead to longer limbs by helping cartilage grow, at least in mice.
Researchers raised baby mice in cold (45F), normal (70F), or warm (81F) temperatures for about two months. The mice raised in warmer temperatures grew longer tibias and femurs (leg bones), and metatarsals (”toes”). The researchers say the effect may be partly explained by increased blood flow under warmer conditions, which promote growth of the cartilage capping the ends of long bones. However, this doesn’t fully explain the results, and they believe temperature also affects other biological mechanisms, like the expression of proteins.
People have long observed that animals, including humans, seem to take on different sizes and shapes depending on the climate of their habitats. One main observation, known as Allen’s rule, says that warm-blooded animals living in warmer habitats tend to have longer limbs to allow for more heat dissipation. In colder climates, stubbier limbs help conserve heat. Bunnies are an often cited example: the Arctic Hare is round and compact while the desert-dwelling Jackrabbit is leggy and long-eared. But these traits were believed to be derived genetically, from one generation to the next. The new study, published in PNAS [subscription required], is evidence that environment also plays an important role, and can take effect within a single generation.
So chalk one up for nurture in nature vs. nurture. Or, at least, it’s a good reason to take that tropical island vacation.
Related Content:
DISCOVER: DNA Is Not Destiny
DISCOVER: How Good Genes Go Bad
Image: flickr / lemoncat1
December 8th, 2008 at 4:30 pm
I’m glad I grew up in Florida!
December 8th, 2008 at 7:10 pm
This doesn’t make very much sense to me. I mean to say, I don’t think this applies to humans. What about all those tall Swedes and Norwegians?
Come to think of it, every person I’ve met in Florida is shorter than me, and I’m 6′3″.
December 8th, 2008 at 11:53 pm
I grew up in Western Australia…definately considered a hot part of the world. I have short arms and legs and don’t think the warm climate helped at all!
In fact, although I am missing a pronounced brow ridge, my stature is very similar to a Neanderthal! Could this be more evidence for my theory that Homo Sapien interbred with Neanderthals? Yikes!
December 9th, 2008 at 12:09 am
I don’t think so.
I am living in Guangzhou, one of the warmest city in China, But I don’t think local people looks leggier.
December 10th, 2008 at 5:11 pm
The Allen’s rule is about ths shape, not the size.
And, unless you have a twin grew up in Alaska, and has longer arms and legs than you (assume you grew up in one of the tropical islands), you can’t make yourself a counterexample to the reported research just because you think you should have longer arms.