Re-creating Extinct Animals

According to a recent article in the New York Times, advances in DNA sequencing and genetic engineering techniques are leading to cautious optimism among scientists that someday it may be possible to bring extinct animals back to life. But it will not be easy. DNA undergoes decay after death, falling apart into little pieces within about 60,000 years. Determining the correct sequence of an extinct species’ DNA requires special DNA sequencers that can analyze the tiny pieces and then calculate how they were aligned in the original intact molecule.

The second step would be to actually reconstruct the deciphered DNA code back into intact DNA once again. One way would be to “reverse engineer” the DNA of a close living relative species until it is similar to the known sequence of the extinct species. So far this has not been possible because of the sheer numbers of base pairs (perhaps half a million) that would need to be modified. But researchers are hopeful that techniques will be available soon to modify up to 50,000 sites at a time. The extinct species’ DNA would then be inserted into an egg of the living relative and incubated in that relative until birth.

How would your students react if it were to be announced one day that an extinct human such as a Neanderthal had been reverse engineered and then born to a modern human or a primate mother?!

Ginkgo Doesn't Prevent Dementia

According to a study in the Journal of the American Medical Association, daily doses of the popular herbal antioxidant Ginkgo biloba neither prevent nor delay the onset of dementia (cognitive impairment). The most common type of dementia is Alzheimer’s disease.

Herbal extracts of Ginkgo remain popular as a memory enhancer, even though previous scientific evidence showed that Ginkgo just doesn’t enhance memory. So don't expect this latest finding regarding dementia to put much of a dent in Ginkgo’s annual sales of over $200 million. Good marketing apparently trumps good science.

Surrogate Grandmother

According to an Associated Press article that appeared in many major newspapers and news services yesterday, a 56-year-old woman gave birth last month to triplets. The event was noteworthy because the three baby girls were actually her biological granddaughters.

Apparently a young couple could not conceive because the woman had had a hysterectomy. So they used in vitro fertilization (IVF) to produce their embryos, which were then implanted into the young woman’s 56-year-old mother.

My class took quite an interest in the many and varied reproductive possibilities raised by modern IVF techniques. They understood the obvious benefit, which is to enable some infertile couples to have children of their own. They also quickly grasped that it could also be used (in combination with preimplantation genetic diagnosis) to choose a child’s sex, to avoid having a child with certain genetic disorders, or even to cure an older sibling of a genetic disorder (See the Current Issue in Human Biology 5th ed., pp. 396-397). But they didn’t come up with this scenario!

Whatever Happened to Golden Rice?

Golden rice was once heralded as a cure for vitamin A deficiency, which kills or blinds children in poorer countries worldwide. But twelve years after its development golden rice is still not being produced and distributed. The primary reason is categorical opposition to all genetically engineered (GE) foods by organizations such as Greenpeace. Greenpeace argues that although golden rice might indeed benefit vitamin-deficient children, acceptance of golden rice would open the door to other GE crops that Greenpeace vehemently opposes.

In the face of intense, well-organized opposition, government regulatory agencies have been reluctant to approve GE crops, including golden rice. The company holding the patent on golden rice eventually gave up, saying there was no money in it. It's still being studied in a few labs by humanitarian organizations such as World Food Day, but don’t expect to see it on grocery shelves any time soon. That's too bad, for golden rice really is a product that could help people in need, as opposed to just helping food producers and manufacturers.

New Nutrient Standards for Packaged Foods

Finally, someone has decided to make it easy for consumers to pick the healthiest packaged foods! A coalition of some of the biggest food companies has teamed up with scientists and the federal government to develop and promote a simple front-of-package logo called “Smart Choices” to indicate that a food meets certain nutritional standards. The standards include limited quantities of total and saturated fats, cholesterol, added sugars and salt, as well as minimum quantities of nutrients for good health, such as calcium, potassium, fiber, and certain vitamins. And like the “Heart Healthy” program originally developed by the American Heart Association, the new program is based on good scientific evidence.

Once consumers understand what the logo means and accept its underlying health assumptions, they can simply look for the logo on the front of the package. “Pattern recognizers” such as myself (who can’t find their favorite products in the grocery store if the manufacturer changes the packaging!) will appreciate the help in picking healthful foods. The logo is a green check mark in a square along with the words, “Smart Choices Program”. For a complete listing of the nutritional requirements to earn the Smart Choices label, visit the Smart Choices website. The logo should begin appearing on products in stores by the middle of next year.

Who Were the Flores People?

Since their discovery in 2004, the origin and identity of a diminutive people who lived on the island of Flores, Indonesia 70,000 to 12,000 years ago have been the hot topic among paleoanthropologists (see the Current Issue in Human Biology 5th ed., pp. 520-521.) The discoverers immediately claimed to have unearthed a new human species, which they named Homo floresiensis. Nay-sayers still dispute the claim, saying that the one skeleton found so far, named LB1, is nothing more than a diseased human with microcephaly.

Well, it seems that the new-species proponents are gaining ground these days. Analysis of LB1’s hands and feet suggest that this is not the skeleton of a modern but diseased human. Her wrist bones and especially her feet are closer to those of Homo erectus, an African Hominid that lived in Africa more than a million years ago. Her feet are so long that scientists think she must have walked with a high-stepping gait and been a poor runner. How Homo floresiensis reached Indonesia and survived there for over 50,000 years is a mystery.

For a good look at the one skeleton unearthed so far, see “When Hobbits (Slowly) Walked the Earth”, Science April 25, 2008, pp. 433-435. You can get the article online at www.sciencemag.org - search for "When Hobbits".

What's in That Energy Drink?

How much caffeine is there in those so-called “energy drinks”? Take a look at the article in press in the journal Drug and Alcohol Dependence (2008) by C.J. Reissig, et al., entitled “Caffeinated energy drinks – A growing problem”, available online at www.sciencedirect.com. According to Table 1 in the article, some of them are pretty high-powered. Most energy drinks have about the same caffeine concentration as brewed coffee, but considering that some drinks come in 16- or even 24-oz sizes, that's a lot of caffeine.

Sales of these products continue to climb. Health officials are growing increasingly concerned by reports of acute caffeine intoxication, dependence, and withdrawal among children. There is also a trend toward the combined use of energy drinks and alcohol among young adults.

Which ones do your students drink? Do they know what’s in them?