Ancestral Modern Humans and Neandertals Might Have Had Children Together. (A Draft Sequence of the Neandertal Genome in Science (2010) 328: 710-722)
What’s behind it?
Scientists keep track of different organisms by giving them strategic names. You might recall the mnemonic “King Philip Cried Out For Goodness Sake” to remember kingdom, phylum, class, order, family, genus, and species. Organisms sharing the same phylum are considered to be more related than those that only share the same kingdom, and only if you are members of the same species are you similar enough to mate and have children. There’s much debate about the proper scientific name for neandertals: are they ‘Homo neanderthalensis’ or ‘Homo sapiens (subspecies) neanderthalensis’? If the former, they are considered a separate species. If the latter, they could interbreed to have children, just as Jean Aule stated in her now-classic book series “Clan of the Cave Bear“. Currently at the Smithsonian Institute in Washington D.C., there’s a new exhibit on Human Origins that insists on the label “Homo neanderthalensis” for the neandertal group – meaning they’re a different species from us. Are they right?
What does the science say?
Scientists were able to sequence DNA taken from three neandertal fossils and compared it to five present-day humans from different parts of the world. A group of genes that are inherited only through the mother show that neandertals as a whole were not simply an ancestral group leading to modern humans: we didn’t evolve through a “Neandertal Phase” of evolution nor are they an isolated offshoot from the evolutionary tree. Perhaps they were a different group of humans. Despite being different, there are several genes that suggest contribution of genes from neandertal to anatomically modern humans of Eurasian lineage, but not for other groups of anatomically modern humans.
The take home message:
This means that if you’ve got a European background, there’s genetic evidence for a great (great, great,…, great) grandfather of you who was a card-carrying neandertal (well, they didn’t have paper, cards or writing, so that’s quite a stretch). The species concept as described here is rather oversimplified. Some organisms are different species but on occasion breed and have young together. You might ask is “were neandertals the same species as our modern human ancestors?” Why did only some of us get only a few of their genes if they mated together?
Examine the crime scene to seek the truth.
image: gamespot.com game: Crime Scene – The Game (for DS)
categories: science, technology, forensic science
The ability to recreate a crime scene as a virtual world may change how forensic scientists collaborate.
http://www.reuters.com/article/idUSTRE5AQ0TR20091127
What is behind it? Forensic science has changed a lot in recent years but the way the forensic scientists work has not. Now, researchers at North Carolina State University are using the Unity game engine to build a tool to let Crime Scene Investigators (CSIs) work together in a virtual world. They’ll be able to take a 3D scan of a crime scene and re-create it in a game world, complete with avatars they can use to act out different scenarios. Just like on Bones, they’ll be able to try out different ideas about how the crime was committed to see if it fits the evidence.
What does the Science Say? The Scientific Method is about developing a theory, designing a way to test that theory, and then carrying out those tests to see if they could be right. When we are dealing with crimes, we are often also dealing with things that are dangerous. Until now, forensic scientists had limited abilities to re-create crime scenes. For example, it just isn’t practical to set up a live experiment to test out a theory about how someone was killed, or to shut down a large museum to test a theory about a theft there. However, we can do this in a virtual world, and with the ability to scan an actual crime scene we can increase the accuracy of the mock-up and thereby increase our confidence that we are testing something realistically.
The take home message: Videogame technology has many applications beyond entertainment. Serious games have become a new way to communicate and learn. Videogames are now used for everything from military recruitment to health, social change, advertising and politics. We are only just starting to understand how and what people learn in video games, and you can expect to see games being used for serious purposes like CSIs more and more.
‘Clan of the Cave Bear’ is Not Entirely Fiction »« Coke as addictive as Coke!?
The same brain processes behind drug addiction can also explain your craving for triple-cheese meat-lovers pizza. http://bit.ly/a2eAc5
What’s behind it? A recent study has shown that the brain pathways involved in forming addictions to drugs are the same ones involved in overeating high-fat/high-calorie or “junk food”. Our brains are just as capable of developing addictions to Twinkies as they are to cocaine. Obesity is growing to become a major health crisis, particularly for the youngest generation. Understanding how our brains react to junk food can help us figure out why we repeatedly decide to binge on Big Macs. But can we really become dependent on our junk food fix?
What does the science say? There are specific parts of our brains that are called “reward” pathways. Essentially it’s the way your brain makes sure you repeat behaviours – it “rewards” you with a pleasurable feeling for your good work. Your typical drugs of addiction like heroine and cocaine activate these pathways and over time cause you to need more and more of these drugs to get that “reward”. You also can start to develop serious negative side-effects until you get your fix. This study says that junk food addiction also acts through these same pathways. The animals in the study easily became addicted to a diet of cheesecake, bacon and sausage-like items, and they continued to overeat even when anticipating receiving electric shocks.
The take home message: Your Mom is right – having unlimited access to junk food can be harmful. It now seems that our chocolate bar habit can develop into an addiction, one we may have serious trouble fighting. We tell kids about the dangers of drugs – do we now include cheesecake and bacon in our pamphlets? Food for thought.
Fighting Crime with Videogames »« Tweet of the Week, March 20
All-Natural Doesn’t Mean All-Safe
Some vegetarians love animals; others just hate plants H/T @deborahblum: Psst. Plants are out to kill you. http://bit.ly/8XBpF9 10/03/17
What is Behind It: It sometimes seems like I hear the benefits of all-natural things everywhere. The kid on the commercial says that his ice-cream is “Naaatural, cuz’ it comes from Nature.” People don’t want things in their food that they can’t pronounce. Cleaning products are advertised as “chemical free”, so people who are afraid of chemicals will want them. The problem is, it is impossible to avoid chemicals. Everything you touch, eat, breath or are is made of chemicals.
What Does the Science Say: The link this week is to a blog about some poisonous plants people have in their homes. Peace Lilies, Poinsettias and Holly regularly send people to the hospital. Even some foods, if prepared improperly or eaten excessively have enough poisonous chemicals to make you ill. Spinach, rhubarb, and beets all have oxalate, the chemical that makes Peace Lilies poisionous. Oxalate is dangerous, no matter where it comes from, because it pulls the calcium out of your blood. Without calcium, nerves and muscles won’t work, and those are kind of important.
The Take Home Message: Just because a chemist makes something doesn’t make it harmful, and just because a chemical comes from the earth doesn’t make it healthy. Poisons were around long before chemists, and chemists make lots of chemicals you depend on every day. People sometimes claim that some drugs are safe because they’re natural. Just because the earth made it doesn’t mean it is safe. By that argument, strychnine is just fine because it comes from a seed.
Coke as addictive as Coke!? »« Tweet of the Week, March 12, 2010
Laser beams to the head can (maybe) fix what’s wrong
RT @stevesilberman Headline du jour: Gold Nanoparticles and Lasers Kill Brain Parasite That Causes “Crazy Cat Lady” Syndrome http://bit.ly/aQFzRd 2010/03/09
What is behind it? A parasite that infects rats and cats can also infect cat owners and cause an illness called Toxoplasmosis. Toxoplasma Gondii, a single-celled creature that lives in cats can be passed on to animals (including us) that come in contact with cat feces. The parasite affects an infected rat’s brain, and causes the rat to find a cat and get themselves eaten. The reaction in people is a bit less extreme. There have been studies that show a link between Toxoplasmosis in humans and psychiatric disorders like anxiety, depression and schizophrenia. Generally though, for people with a healthy immune system, Toxoplasmosis only makes them feel like they have the flu.
What does the Science say? Researchers in Australia have found a way to make teeny-tiny pieces of gold stick to toxoplasma gondii. The plan is to shoot the gold with a laser that can pass through body tissue harmlessly. The gold would absorb the laser energy, heat up, and fry the critter it is attached to. Since 15% of Americans have Toxoplamosis, a new treatment would be nice.
The take home message. The new science achievement in this story is the ability to attach gold nanoparticles to parasites. Science has known for a while that shooting gold particles with a laser causes them to get super hot. Two questions remain. Can they find the right type of laser to go through the body harmlessly and still heat up the gold? And can they convince the person down the street with two dozen cats that lasers and being injected with gold particles is a good idea?
Tweet of the Week, March 20 »« Tweet of the Week, March 5, 2010
Marijuana Use Causes Psychosis (Or Does it?)
Psychosis may be a long term effect of smoking pot. Smoking pot may be self-medication for psychosis. http://bit.ly/cR5ARw 2010/03/02
What is behind it? A recent study shows that people who have used marijuana for several years have a higher than normal chance of also having trouble recognizing what is real. Symptoms of psychosis, such as hallucinations and delusions, showed up twice as often in people who had used marijuana for six years or more. Anyone familiar with TV sitcoms showing pot-smokers is not surprised at the correlation and headlines shout that pot causes psychosis.
What does the Science Say? The study shows that pot-smoking and psychosis often go together. They are correlated. It doesn’t show that pot causes the psychosis. In fact, it may be the other way around. Someone who is prone to psychosis might feel more normal when using pot and end up using it more often than other people as a form of self-medication.
The take home message: People, even the media, often jump to conclusions. Just because things go together (correlation) doesn’t mean that one causes the other (causation). It is easy to assume that smoking pot turns otherwise normal people into someone like Leo from That 70′s Show. We can’t rule out, however, that maybe Leo tokes up because he was losing his connection to reality already.
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