Blogs / Discoblog

Though some believe humans have reached the dead-end of our evolutionary journey, small skink lizards (Lerista) seem to still be in the thick of it. Skink lizards already have elongated, snake-like bodies with relatively small, shrunken legs. Now, new research [pdf] finds that the lizards are giving up walking for good, and have been rapidly evolving away their limbs.

Adam Skinner of the University of Adelaide performed a genetic analysis on several species of skink lizards with different sized limbs. He found that there have been at least ten independent reductions in limbs throughout the lizards’ evolution, without any signs of reversal. Some species now have fewer digits (lizard fingers) while others have lost whole limbs. Complete loss of limbs could have occurred in as little as 3.6 millions years—a blink of an eye in evolutionary terms.

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Religion has a funny way of dividing people. But religious fervor and intolerance may also keep you from getting sick, according to evolutionary biologists Corey Fincher and Randy Thornhill of the University of New Mexico. They propose a theory that says religious diversity was an evolutionary adaptation to keep groups of people separate and prevent them from infecting each other with diseases.

The researchers noted that religious diversity varies significantly across the globe. Why does Brazil have 159 religions while Canada only has 15? Fincher and Thornhill believe there is a relationship between geography, climate, and religious diversity. Since warmer locales harbor more infectious diseases, it was a good survival strategy to keep to yourself and religion enforced isolation.

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Attention criminals: You might want to consider changing your last name to Smith, the most common—and least traceable—last name in both Britain and the U.S. Why? Because men may be carrying a name tag in their genes.

The Y chromosome is passed from father to son with little variation, and in many cultures, so are last names. Researchers at Leicester University in the U.K. seized on this coincidence to study the genetic linkages among British surnames. She found that men who share the same last name, especially the less common ones, are likely to share a common ancestor. This means your Googlegänger is probably a long lost relative after all.

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This is it. The evolution of Homo sapiens is complete, says British geneticist Steve Jones—not because we’ve reached some pinnacle of perfection, but because we’ve run ourselves into an evolutionary dead end. Jones argues that the structures of contemporary society have jammed the three main drivers of evolution: natural selection, mutations, and random change.

He spoke yesterday at the University College London, delivering a lecture entitled “Human Evolution is Over” (in case you had any doubts as to his hypothesis). Here are his three main points:

1) Fewer early deaths. If everyone lives to reproductive maturity (in the developed world, nearly 98 percent of people survive to the age of 21), natural selection can do little work.

2) Fewer elderly fathers. As a man ages, the likelihood of genetic mutations in his sperm increases dramatically. It used to be common for men to father many children with many different women well into old age, but this is less acceptable in today’s society.

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Break a mirror and you’re stuck with bad luck. Walk under a ladder and you’re tempting fate. Sound ridiculous? Scientists believe such beliefs may be genetic, part of adaptive behaviors passed on to create an evolutionary advantage to surviving impeding danger.

Boiled down, a superstition is the belief that one event caused another event, without any evidence of the link. “All animals will display behaviors that imply a causal relationship that isn’t there,” says Kevin Foster, evolutionary biologist at Harvard University. Foster uses a pigeon as an example: The pigeon will take flight if it hears a hand clap, the same way it would react if it heard a gun shot.

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We know that women can look at a man’s face and judge whether he has the potential to be a good father. But looks can only go so far—it’s really your genes that matter. In the latest study on love and attraction, a group of scientists found that people in Europe and the U.S. choose partners with dissimilar immune cells, ultimately leading to children with stronger immune systems.

The researchers measured the Major Histocompatibility Complex (MHC)—a large region of the genome linked to the immune system and body odor—of 30 European American couples, and compared them to 30 Nigerian couples.

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Archaeologists excavating a burial site near Nazareth dating back to between 6750 and 8500 B.C. found the area littered with shells, axes, and other artifacts—no surprise there. But something else also caught their attention: a high number of phallic figurines.

It’s not unusual to find reproductive-themed artifacts in grave sites from this period, says study leader Nigel Goring-Morris of the Hebrew University. But this period of history, not so long after the agricultural revolution, typically produced more female figurines, associated with the fertility of the land. Even though most of the 65 people buried in this 10 meters by 20 meters plot were young men, he says, the finding is an odd one.

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A millennium and a half after the fall of their empire, ancient Romans might still be wreaking havoc on the European continent.

On average, Northern Europeans are more resistant to HIV infection and take longer to develop AIDS than Southern Europeans, and French researcher Eric Faure thinks that represents the legacy of the Roman Empire, strangely enough. There’s a gene variant in question, called CCR5-Delta32, which produces proteins that the HIV virus has trouble attaching to. But while in some areas of Northern Europe 15 percent of people carry this gene variant, only 4 percent of Greeks have it. In fact, if you look at the distribution of places where few people carry the gene, Faure says, the map looks suspiciously like that of the extent of Roman rule.

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If a creature was big, slow, and delicious, there’s a good chance that early humans hunters found it too good to pass up.

Researchers combing the Red Sea have identified a new species of clam, a giant one that could measure more than a foot in length and may have been one of our ancestors’ favorite meals. The oversized mollusk went undiscovered for so long because it accounts for only one percent of the current population of clams. However, checking the fossil record, the scientists found that the giant clam once made up 80 percent of the population, then dropped off precipitously around 125,000 years ago, a date that roughly coincides with early humans coming out of Africa.

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Proponents of marriage like to toss around the statistic that married people (and married men in particular) are happier and healthier than the wretched ranks of the unwed. But new research has found that the happiness/health gap is narrowing, not because the married crew is losing its happy glow (though that may indeed be occurring), but because the single component is getting happier.

The study, led by Hui Liu, assistant professor of sociology at Michigan State University, used data from the National Health Interview Survey from 1972 to 2003. The researchers found that while the self-reported health of the married is “still better than that of the never-married,” the “gap has closed considerably.” Single women shouldn’t rejoice just yet: The uptick was due overwhelmingly to improvements in the health of never-married men. Liu thinks that this result may be “partly because never-married men have greater access to social resources and support that historically were found in a spouse.” (Female robots, perhaps? Or Internet porn?) Still, single women also saw an increase, and the singles health boost also spread across racial lines to both blacks and whites.

For those with one or more marriages in their past, the results aren’t as clear—the health of the the divorced, widowed, and separated worsened from 1972 to 2003 relative to their married peers (though whether entering into a second or third marriage increased your health wasn’t mentioned). So maybe the statistic should be revised to something like “first marriages and single-malehood, and possibly second and third marriages will make you happier and healthier.” Happy dating!

Image: iStockPhoto