Stories tagged Life Science

Nov
26
2006

Neanderthalensis-Sapiens love child?: DNA sequencing may provide the answer. Photo courtesy of Mark Ryan's mother
Neanderthalensis-Sapiens love child?: DNA sequencing may provide the answer. Photo courtesy of Mark Ryan's mother

Did Neanderthals, the stocky, muscular human relatives that dominated Europe until 30,000 years ago, have the ability to communicate through language? And if so, did any of their chat sessions ever lead to dating and possibly mating with us, their not-so-distant cousins?

DNA extracted from the thigh bone of a caveman who lived 38,000 years ago in Croatia may supply scientists with the answers to these and other questions.

Two studies, one in Germany, the other in California, have reported new and exciting techniques for compiling the entire genome for Neanderthals, modern humans closest and most recent evolutionary link. Their research results, reported in the journals Nature and Science, respectively, convey they have demonstrated independently that it is now possible to recover the Neanderthal genome. Just a few years ago, the idea of doing this kind of sequencing was considered hopeless.

Dr. Svante Paabo who led one project at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany said that one million units of the estimated 3.2 billion units of Neanderthal DNA have already been mapped.

What has made this possible is a new DNA sequencing machine developed by a Branford, Connecticut company called 454 Life Sciences. The new sampler uses firefly light to sort through and catalogue vast amounts of fragmented DNA.

Dr. Paabo also shared some of his precious sample of Neanderthal DNA with Edward M. Rubin of the Joint Genome Institute in Walnut Creek, California. Using a different method, Rubin’s team identified 62,250 units of Neanderthal DNA.

Richard G. Klein, a Stanford University paleoanthropologist not involved in the studies, found the results “monumental.” He added that the full Neanderthal genome would resolve many longstanding questions about Neanderthals and their connection to modern humans, including physical and behavioral differences.

Of particular interest is whether Neanderthals could speak and had developed a language. The FOXP2 gene is thought to be one of the last evolving components leading to language development and has shown significant change since human-chimpanzee split occurred about six million years ago. If the Neanderthal genome is fully retrieved, and the FOXP2 gene more resembles the chimp version, then the thinking is that language development is less likely.

Dr. Paabo’s team has estimated the establishing Neanderthal population size to be about 3,000 individuals, while Dr. Rubin’s team reports that human and Neanderthal genomes are at least 99.5 percent identical. However, both research teams think it unlikely the two species interbred but the idea cannot be completely ruled out.

The extraction of readable DNA poses problems for scientists. The samples are often contaminated by bacterial DNA that attacked the remains when they were fresh or other human DNA left from curators or scientists handling the specimens.

On top of that, DNA begins to quickly degrade into short fragments after death making it tricky to locate a sample that has somehow survived. Dr. Paabo searched through museum collections all across Europe before finally finding one that satisfied his stringent criteria. It was a small bone from a cave in Croatia that had languished in a box of insignificant and relatively little-handled fossils. Only about 6 percent of the DNA present was Neanderthal, but with the new sequencing machine it should be more than enough to retrieve the specie’s gene sequence.

With 1 million units of Neanderthal DNA already mapped, Dr. Paabo estimates the rest should be completed in about two years.

SOURCES and MORE INFO:

BBC
454 Life Sciences Neanderthal info
Genome Research
Human Genome Project

Nov
17
2006

A new vaccination strategy in India could finally eliminate polio by the end of the decade.

In northern India, particularly Uttar Pradesh and Bihar, the polio virus persists, despite good vaccination coverage, due to overcrowded living conditions and poor sanitation. Researchers at the Imperial College in London say that the three polio strains in the trivalent vaccine can interfere with each other inside the body, producing immunity to one strain but not another. So switching from a vaccine that protects against three strains of polio to a vaccine that protects only against the dominant one, along with stepped up vaccination efforts, could help eliminate the virus from its few remaining reservoirs.

More polio stories on the Buzz:

Polio in Minnesota

Minnesota's polio hero

Polio jumps an ocean to Indonesia

Nov
15
2006

Two years ago, a scientist in Australia has a really lucky day. Tired after driving for several hours, he stopped to stretch his legs and -- boom! -- he tripped over a 100-million-year-old pterosaur jaw. (Pterosaurs were flying reptiles that lived at the same time as dinosaurs. The Science Museum has one hanging in our main lobby.) The jaw bone was encased in rock; after two years of careful preparation, the bone is finally free and can be studied by scientists.

(OK, so it wasn't a technically a dinosaur, and it was actually off to the side of the road, but c'mon, how often do I get to reference my favorite bad song of the Seventies?)

Nov
14
2006

The Bell Museum of Natural History is hosting a CAFE SCIENTIFIQUE tonight (Tuesday, November 14) at 6pm at the Varsity Theater in Dinkytown. (There's a $5 suggested donation, but you can attend for free.)

This month, Cafe Scientifique explores the science and politics of genetically modified organisms, or GMOs. What is a GMO? How and why have researchers been modifying the genetic makeup of plants and animals, and what are the possible risks and benefits of this type of research? Speakers from the University of Minnesota will discuss the science as well as the policy concerns of genetically modified organisms.

Guest speakers are:

  • Professor Anne R. Kapuscinski, Ph.D., University of Minnesota Department of Fisheries and Conservation Biology, Sea Grant Extension Specialist in Biotechnology and Aquaculture
  • Jennifer Kuzma, Ph.D., Interim Director and Assistant Professor at the Center for Science, Technology, and Public Policy, Humphrey Institute, University of Minnesota.

Dr. Kuzma was featured on Minnesota Public Radio's Midmorning show this morning, discussing the politics of genetically modified foods and potential safety issues.

Do you have questions about genetically modified crops? Do you try to avoid genetically modified foods at the grocery store? What worries you or excites you about the potential of GMOs?

Nov
03
2006

All week, the comic strip "Non Sequitur" has been running gags about whether or not a duck's quack echoes. The joke is that once someone asks you the question, you can't stop thinking about it until you know the answer. It's Friday, and I've resisted the temptation to look it up until now, but I've caved!

I can't think of a single scientific reason why a duck's quack WOULDN'T echo, but I had to look it up anyway. The good news? I'm hardly the first person to do it. When I googled "Does a duck's quack echo?" I got 105,000 hits, including links to some real research.

Here are some of the best sources of info:

BBC news: "Sound science is quackers"

Salford University: "The duck's quack echo myth" (This is an awesome page.)

The Straight Dope: "Is it true a duck's quack won't echo?"

Science Made Simple: Does a duck's quack echo?"

About.com (Urban Legends and Folklore): "A duck's quack doesn't echo"

MadSci Network: "Why won't the quack of a duck echo?"

SPOILER: Yes, a duck's quack, like any other sound, echoes. But the WAY a duck quacks, with the long "AAAAAACK" sound at the end of the call, tends to mask echoes, making them hard to hear.

Oct
26
2006

A manatee: Photo courtesy US Geologic Survey
A manatee: Photo courtesy US Geologic Survey

Rescuers from the US Fish and Wildlife Service are trying to capture a manatee that has strayed far from home. These large, gentle creatures normally live in the Gulf of Mexico. But one half-ton hombre swan 700 miles up the Mississippi River and is now inhabiting the harbor at Memphis, Tennessee!

Scientists are concerned for the animal's health. Nearly hairless, manatees need water 68 degrees or warmer. The river is a little bit chillier than that, and biologists worry that the creature’s digestive system could shut down. They are trying to corral it and move it to Sea World Florida, where it can receive medical attention.

Oct
26
2006

Dermestid colony: (Courtesy US FWS)
Dermestid colony: (Courtesy US FWS)

First of all, check out the Museum's dermestid cam. (Dermestid beetles are scavengers—organisms that eat the remains and wastes of other plants and animals.)

If you're at the museum, go to the Science Buzz station in the Mississippi River Gallery on Level 5 to watch a live feed from the dermestid colony. Or, even better, you can look into the colony itself from the queue for the 3D theater, down by the Triceratops on Level 3.

It's a dirty job, but someone has to do it.
Rot happens. And scavengers—like dermestid beetles and turkey vultures—eat rotting things. We associate rot with death, but it also makes life possible. How? As dead plants and animals decay—helped along by scavengers—the nutrients inside their bodies are returned to the soil. That helps new plants grow and starts the food chain over again. Without scavengers and decomposers, we’d be up to our necks in dead stuff. Think of them as the ultimate recyclers!

Bad to the bone
Adult dermestid beetles are small, black, and hairy with patches of white. The brownish-gold larvae have blunt heads and tufts of long brown hair on their rear ends. And they’re hungry—an infestation of dermestid beetles can destroy a museum’s collections. So why does the Museum keep a dermestid colony? The insects eat old, dried out, mummified stuff—leather, fur, feathers, skin, hair, wool, silk, and dried food products. They eat it all, right down to the bone. So they’re valuable for cleaning skeletons.

Many insects lay eggs and develop on dead bodies, eating them as they go. Blow flies—among the first to colonize a body—come and go fairly quickly. Dermestids, on the other hand, can be found around a body as long as there’s anything to eat—from near the time of death to years later. The kinds of insects that a scientist finds with a corpse, and the ages of the larvae and pupae, can be used to estimate when the death occurred. So insect scavengers can also help solve crimes.

Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone
Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone

Set up a beetle habitat of your own
It’s easy to observe the transformation of complete metamorphosis when you set up your own mealworm colony. Mealworms, the larval form of darkling beetles, are commonly sold in pet stores as food for reptiles and amphibians. These beetles are completely harmless and cannot bite or run very fast. As long as they're well fed, adult beetles won't try to escape their habitat.

Materials

  • A large plastic bin, 2–3” deep
  • A bag of oat or wheat bran
  • Two layers of burlap or cheesecloth, cut to fit inside the bin
  • Light all-purpose household oil to coat the outside edges of the bin when the beetles mature
  • Approximately 50 mealworms, available at pet stores or bait shops

What to do

  1. Lay a square of burlap in the tray.
  2. Pour 1–2” of bran into the tray.
  3. Add the mealworms.
  4. Lay a square of burlap or cheesecloth on top of the bran. (This gives the older larvae a place to pupate.)
  5. Add a fresh slice of apple, potato, or lettuce on top of the bran every week. This will provide all the moisture your mealworms need. Add fresh bran as the level goes down.

Simple experiments
Develop some simple experiments to observe behaviors and record major events in the mealworms’ life cycle:

  1. Measure individual mealworms weekly and record growth rates on a graph.
  2. Place a few “control” mealworms in the refrigerator to see if they develop at the same rate.
  3. Place mealworms in the centers of some Styrofoam meat trays. Cover half of each tray with black construction paper, and hypothesize whether the mealworms will move to the light side or the dark side of the tray.
  4. Record the number of times the mealworm molts, or sheds its exoskeleton, as it grows.
  5. Record the number of weeks until their mealworms pupate, and how long they remain in the pupae.
Oct
12
2006

Stop bleeding fast: photo by crystal via wikimedia
Stop bleeding fast: photo by crystal via wikimedia

Super quick fix for bleeding.

Last June 4th, I reported that MIT researchers used a self-assembling peptide nanofiber scaffold to repair severed brain structures in blind rodents and restore their sight. Those same researchers noticed the material's dramatic ability to stop bleeding in the brain and began testing it on a variety of other organs and tissues.

In a study published online October 10 in Nanomedicine the researchers report that the liquid controlled bleeding in rodents within 15 seconds in seven other wound types, including cuts to the spinal cord, liver [view video here] and femoral artery as well as skin punctures.

Platelets not needed

The liquid does not seem to form a conventional blood clot, the group notes. Electron microscopy turned up no sign of the platelets that would normally gather in a clot. The proteins might instead form tangles that act like hair blocking a drain, Ellis-Behnke suggests.
The gel eventually breaks down into amino acids, the building blocks of proteins, that can be used by surrounding cells for tissue repair.

This discovery has created lots of excitement, especially by surgeons. Still, they caution that extensive clinical trials are needed to make sure the materials work properly and are safe. The MIT researchers hope to see those crucial human trials within three to five years.

Read more at: New Scientist Tech and Scientific American

Oct
12
2006

Wobbly planet Earth: Photo courtesy NASA.
Wobbly planet Earth: Photo courtesy NASA.

The extinction of rodents and other mammals have been linked to variations in the Earth’s tilt and orbit, according to new research published in the journal Nature.

Dutch scientists studying 22 million year old rodent fossils in central Spain found that the rise and fall of the mammal species correlated with cooling periods due to changes in the Earth’s behavior. Rodents offer one of the best fossil mammal records and are excellent indicators of seasonal changes because of their short life spans.

"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change," Dr Jan van Dam, of the Utrecht University in the Netherlands, said.

The researchers discovered two cycles associated with changes in climate, habitat and food availability are linked to the disappearance of rodent species. One cycle, which lasts 2.4 million years, is linked to variations in the Earth’s orbit. The other 1.2 million year cycle is related to changes in the tilt of the Earth’s axis. Both cycles would cool the Earth, allowing the expansion of ice sheets and causing species to adapt or die out.

Right now Earth is in a relatively circular orbit and about 700,000 years away from the next period of axis stability.

"The environment is responsible to what happens to species," said Van Dam. "Biological factors are secondary, according to our results."

However, Larry Ciupik, an astronomer at Chicago’s Adler Planetarium says volcanic activities, plate tectonics and the amount of carbon dioxide in the atmosphere also contribute to species turnover.

MORE INFO
New Scientist
LiveScience.com

Oct
05
2006

Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.
Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.

I work at the Science Museum and I often learn unusual things during the course of my day. Some things are funny, some I store away to pull out in a Cliff Claven moment, and others make me want to run screaming to my desk to put them into this blog.

This is one of the latter.

Yesterday I learned that herrings may communicate with one another through their anuses by farting. I almost exploded when the person leading the meeting casually mentioned this fact. I ran back to my computer, and sure enough. Researchers at not one, but TWO institutions are studying the phenomena. Both the Institute of Coastal Research at the National Board of Fisheries in Sweden and the University of British Columbia, Vancouver have researchers looking into the matter.

Before this remarkable discovery, it was known that herrings communicated with one another through sounds produced by their swim bladder. Researchers thought that all the sounds they heard coming from the herring were coming from the swim bladder. But, and I am laughing as I type, they noticed that a stream of bubbles would leave the herring’s anus in time with the sounds they were hearing. Sure enough, they are connected, and that sound was soon dubbed by the quick-thinking researchers as a Fast Repetitive Tick (or FRT, if you will).

Researchers note that the unlike the gas we pass, these sounds are not produced by the digestive process, but rather a connection between the swim bladder and the anus. The exact purpose or reason behind the FRTs is not exactly known. One theory is that is a way for the herring to communicate with each other at night. Another is that is an anti-predator tactic. Seriously. Or, it could just be an incidental release of air from the swim bladder as the fish adjusts its buoyancy.

You can hear the herring communicating in this manner here.