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[lang_en]What if there were no men anymore? It could happen. The Y-chromosome has been shrinking for millenia. A few years ago, the media was abuzz with stories of the “Incredible Shrinking Y.” Most said that the Y was in no danger of completely withering away, but some argued the other side.

Y So Lonely?

The fact that it doesn’t have a matching pair poses a bit of a problem for the Y chromosome.

All the other chromosomes come in two copies. Every time a cell divides, mistakes in genes can creep in. In paired chromosomes, that means that if there is a mistake on one chromosome, a cell can always get the correct gene sequence from the other chromosome.

Over time, mistakes have crept into the Y chromosome, too. But every time a gene on the Y chromosome went bad, it basically disappeared. Scientists theorize that the X and Y chromosome started out with about the same amount of genes — about 1,000. Today, the Y chromosome has less than 80 genes.

Hope for Y’s Future

Some geneticists think the Y chromosome is now little more than a genetic wasteland that will eventually just disappear. If that were to happen, it would certainly spell the end of sexual reproduction.

But David Page of MIT’s Whitehead Institute vigorously disagrees. “At the same time that it is continuing to lose genes, it’s found some new ways of replenishing itself,” Page says.

-Joe Palca

So imagine that the “some geneticists” are right, and the chromosome is a disappearing wasteland. Then what? Look no further than the Whiptail lizard.

Whiptail lizards are long slender lizards with pointed snouts and long tails. They are generally tan, brown or olive in color and may have lighter stripes or spots of yellow or white.

Whiptails are found throughout the Sonoran Desert region from sea level up to 8000 ft. They inhabit low desert scrub, as well as grasslands, woodlands and pine forests. They are often found under rocks or in leaf litter. Whiptails eat a variety of insects and occasionally smaller lizards.

Most species reproduce sexually and lay 1 or more clutches of 1-6 eggs in late spring or early summer. In Arizona, however, approximately 60% of of whiptail species reproduce asexually. These species consist entirely of genetically identical females that lay unfertilized eggs. Eggs typically take 60-75 days to hatch.

This is a species where we are literally watching as male lizards are phased out, one subspecies at a time. Future of humanity? I’m not going to bet on it, but I’m certainly not going to rule it out, either.

-Chelsea Leroux[/lang_en]