Modern Science Archives : Page 41 of 53 : Proslogion

Silver Foxes Change Rapidly… and in Surprising Ways

silver_fox1 — In the experiment, farm-bred silver foxes went from being agressive towards people (left) to being friendly (right) in as little as six generations. (Photos from reference 1)

I recently read about a fascinating experiment that has been going on in Russia for the past 50 years. Dmitry K. Belyaev acquired some silver foxes from a farm that breeds them for their fur. The farm started about 50 years prior to the experiment, so several generations of foxes had experienced human contact to some degree. However, the foxes still did not care for human contact and were quite aggressive if they were forced into such contact.

Belyaev took this group of foxes and began trying to develop a new trait: tameness. Each fox was exposed to a human for a specific amount of time at specific ages. The fox was then evaluated based on how well it reacted to the human, and only the foxes with the best overall reactions to humans were bred. In a mere six generations, some foxes were born that not only enjoyed human contact, they actually craved it! This behavior became characteristic of the entire population, so that the foxes now behave like dogs – wagging their tails, whimpering, licking people, and generally doing all they can to interact with people.¹

Now these results are cool on at least two levels. First, I was shocked at how quickly the foxes adapted to human socialization. For human-friendly foxes to appear in a mere six generations just astounds me. I know that dogs were domesticated from wolves, but I always imagined that it took a long, long time. After all, a lot has to change in order to take an animal that avoids people and is aggressive towards them and turn it into an animal that not only jumps up on your lap to cuddle with you but begs to be able to do so! According to this experiment, however, the change can happen quickly. Second, I just think it would be incredibly cool to have a pet fox. From time to time, I see a wild red fox in the neighborhood where I live. I would love to have such a beautiful animal as a pet!

Those are the cool aspects of the experiment. However, there are a lot more interesting aspects to the experiment, and they indicate that we still have a lot to learn when it comes to genetics.

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The Debate is Settled on Another “Vestigial Organ”

Most dolphins are born with hairs on their rostrum. However, those hairs quickly fall out, leaving empty pits behind. The photograph on the left gives a rather striking example of these pits, which are often called vibrissal crypts. For a long time, there has been controversy in the scientific literature regarding what these pits are. Some have contended that they are leftover vestiges from when the ancestors of dolphins had whiskers ¹, while others have suggested that they serve some sort of sensory purpose.²

Wolf Hanke and his colleagues set out to settle this controversy for at least one species – the Guiana dolphin (Sotalia guianensis). As they say in the introduction to their study ³

These vibrissal crypts are often described as vestigial structures lacking innervation and the characteristic blood sinuses [15,16], which are probably reduced in favour of the sonar system.

However, they indicate that there are some data that contradict this this idea, so they decided to do a detailed study of the Guiana dolphin’s vibrissal crypts. First, they examined the microscopic structure of the tissue. They noticed that each crypt had about 300 nerves plugged into it, which is more than the number of nerves plugged into a rat’s whisker. It seems obvious that there wouldn’t be such a large amount of nerve tissue wasted on a useless structure.

In addition, the tissue looked a lot like the electroreceptors found in the bill of a platypus which allow the platypus to detect electrical fields in the murky water where it lives. Why would the platypus want to sense electrical fields? Because whenever a muscle contracts, it sends out a weak electrical signal. As a result, a platypus can find prey without seeing or smelling it. All the platypus has to do is find the electrical signals being emitted by the prey’s contracting muscles.

So the microscopic structure of the tissue in the vibrissal crypts makes it look like the Guiana dolphin uses them to detect electrical signals, just as the platypus does. The scientists decided to put this idea to the test, and the results were astounding.

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You Never Know What They Will Discover…If You Let Them!

tkncm_low — Tetrakis(nitratoxycarbon)methane, a theoretically-possible molecule discovered by ten-year-old
Clara L. Lazen.

Back when I was on the faculty at Ball State University, I was cleaning some platinum foils that I was using in my research. I brushed them with ethanol and then put them in a flame until they glowed red hot. By accident (which is often the way scientific truths are discovered), I found that if I passed a platinum foil back over (but not into) the ethanol while it was hot but no longer glowing, it would start to glow red hot again. When I pulled it away from the ethanol, it would stop glowing, but if I put it near the ethanol soon enough, it would once again begin to glow. I was fascinated by this effect and played with it for quite a while. The next day, I was teaching chemistry to a class of gifted-and-talented high school juniors, and I showed them what I had found. Then I gave them the “explanation” for it.

Platinum is a known catalyst, which means it tends to speed up a reaction without being consumed. In addition, alcohols are known to decompose into another class of organic molecules called “aldehydes,” and that happens quickly in the presence of the right catalyst. Thus, it was “obvious” what was going on: the platinum was catalyzing the decomposition of ethanol vapors into aldehyde vapors (specifically, acetaldehyde vapors), and the energy released by that reaction heated the already-hot platinum sufficiently to start it glowing red again. The students oohed and ahhed over the effect, and they dutifully wrote down my explanation in their notes. At the end of class, however, one of the students patiently explained to me that my analysis couldn’t be correct.

You see, she had done something I hadn’t bothered to do. She used the appendixes in the back of her book to calculate the energetics of the decomposition of ethanol into acetaldehyde, and she found that the reaction actually absorbed energy. It did not release energy. Thus, it could not be heating the platinum! Needless to say, I was rather impressed with this young lady’s analysis. The next class period, I told all the students that I was wrong and that I would look into the real explanation. However, I couldn’t find anything in the chemical literature that was relevant. As a result, I asked the young lady if she would work under my NSF research grant that summer and figure out what was really going on. She was surprised that I thought she could figure something like that out, but she said she would be happy to try.

It took her only a few weeks to learn what was really going on. Yes, the platinum was catalyzing the decomposition of ethanol into acetaldehyde, but that wasn’t what was causing the effect. Instead, the other product of that decomposition, hydrogen, was reacting with the oxygen in the air to make water. That reaction released the energy which caused the platinum to heat up enough to glow red hot again. This young lady’s work was so solid and elegant that we published a paper on her explanation of the effect.¹

Why am I telling you this story? Because a friend of mine alerted me to an article that brought it all back to me in vivid detail.

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Motherhood Has a Lasting, Cellular Impact!

In pregnancy, the placenta is a barrier between the baby and the mother (Gray's Anatomy Image)

A very interesting writer named Amanda Read is a Facebook friend of mine. She has an amazingly diverse reading list, and she often posts things that she has read and found interesting. A while back, she posted a story about how a baby’s cells reside in his or her mother long after the baby is born, and that they may aid the mother in healing certain kinds of tissues. When I read the story she posted, I immediately expressed my skepticism. After all, we have an amazing immune system that fights any cells that are identified as foreign. Even though the baby develops in the mother’s body, there is a placenta that forms a barrier between the mother and the baby. It was obvious to me that a baby’s cells could not pass across the placenta, because the mother’s immune system would immediately attack them as foreign cells.

Well…it turns out that I was dead wrong. When I actually looked into the story, I found that while the story was a bit biased, the fact is that a baby’s cells do, indeed, cross the placenta, and they do, indeed, stay with the mother for a long, long time. In addition, the mother’s cells cross the placenta and stay with the baby for a long, long time. This phenomenon is called fetomaternal microchimerism, and believe it or not, scientists have known about for quite some time.

The first paper that discussed this phenomenon was written by Herzenberg and his colleagues in 1979. Published in The Proceedings of the National Academy of Sciences USA, the paper details how they found cells with Y chromosomes in mothers after pregnancy, but only if the baby was a male.¹ Since a woman has no Y chromosomes, it was clear that the cells they found didn’t belong to the woman. The authors didn’t have the ability to use genetic testing to confirm that the cells belonged to the baby, but they showed that these Y-chromosome-containing cells appeared only when the mother had a baby boy. Thus, it was clear that the cells must be coming from the baby.

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The Appendix: More Evidence That the Creationist Prediction Is Correct

For many, many years, evolutionists have called the human appendix a vestigial organ. In their view, our supposed ancestors needed a large cecum for digestive purposes. Over time, however, we evolved so that we didn’t need such a large cecum anymore. However, mutation and natural selection never got around to completely removing the large cecum and, as a result, we have a leftover, useless, small version called the appendix. As one evolutionist put it:¹

…we have an appendix (a small remnant of a prior ancestor species’ intestinal sack) which not only is of no use to us but which can sometimes kill us when it gets clogged up and infected! What kind of god or other “intelligent designer” would design organisms with such useless, imperfect, wasteful, and sometimes even harmful physical features?

As I wrote previously, there is strong evidence that this evolution-inspired idea is incorrect. Evidence indicates that the appendix acts as a safe reservoir of the beneficial bacteria that usually populate your intestine. That way, when you have a disease that wipes out those bacteria, they can quickly repopulate your intestine so as to restore your normal level of health. This function conforms quite nicely to a creationist prediction made several years before this evidence began to mount.

Of course, a few pieces of evidence do not make a clear-cut case. As a result, it is important to test the idea that the appendix has a vital function in the human body by making predictions based on that assumption and then seeing whether or not the predictions are confirmed by the data. This has recently happened. In 2007, some medical scientists wrote a paper suggesting that the appendix served as a reservoir for the beneficial bacteria that live in our intestines.² As a result, they predicted that if specific intestinal diseases were investigated, it should be found that people who have those diseases are better able to fight them if they have an appendix.

Well, a study that tested this prediction was recently published, and the prediction was dramatically confirmed.

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More on Comparing the Human and Chimpanzee Genome

dna1 — A schematic representation of DNA, concentrating on the nucleotide bases that encode biological information. (Click for credit)

How similar is the human genome to the chimpanzee genome? Since both genomes have been fully sequenced, you would think that would be an easy question to answer. Unfortunately, it is not. After all, how do you compare the genomes of two different species? You might think that the most straightforward way would be to simply line the two genomes up and see how much they overlap. If that’s the way you are comparing the genomes, then the answer is relatively easy. Based on the analysis done by the Chimpanzee Sequencing and Analysis Consortium, about 75% of the two genomes overlap well. There is an error rate of about 3% within that overlap, however, so the two genomes are 72% similar based on this kind of analysis.

The problem is that simply lining two genomes up and looking for overlap might not be the best way to compare them. After all, it seems that genomes have been designed to change. Genes and their regulatory agents can move around, be copied to different parts of the genome, etc. As a result, when you compare genomes between species, you might need to be a bit more careful in how you do it.

One popular means by which geneticists compare genomes today is by looking at chunks of DNA in one organism and comparing them to the genome of the second organism. One common way to do this is to use the computer program called BLAST (Basic Local Alignment Search Tool). This program takes a chunk of DNA from one organism and splits it into a series of short sequences called “words.” It then looks through the genome of the second organism, trying to find regions where there is a lot of similarity with the words generated from the first organism. If the similarity is above a specified threshold level, BLAST scores it as an overlap, keeping track of precisely how similar the two sections of DNA are within that overlap.

In other words, rather than looking for long stretches of DNA that overlap between two organisms, BLAST looks for smaller regions of overlap. This makes sense, of course, since a given gene or a given regulatory piece of DNA takes up only a small part of the total genome. By comparing small parts of two genomes rather than the genomes in their entirety, you are better able to find the functional units within the DNA that are similar.

So…when scientists use a comparison method such as BLAST, how similar are human and chimp DNA? Surprisingly, the jury is still out on the definitive answer to that question!

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Antiboitic Resistance Doesn’t Dissapear Quickly

sow_piglet — A piglet nursing (Image in the public domain.)

Those who are not very familiar with the phenomenon of antibiotic resistance often use it as evidence to support evolution. However, those who understand genetics and biochemistry do not. That’s because most antibiotic resistance arises from genes that have been around for a long, long time. For example, an interesting study published just this year showed that many of the genes involved in antibiotic resistance were around with the mammoths, long before antibiotics were available. This seems to indicate that rather than being a response to the human production of antibiotics, at least some antibiotic-resistance genes are necessary for the proper survival of bacterial populations.

A new study provides additional evidence for this idea. In the study, researchers analyzed pigs that were kept on a pig farm known to be antibiotic free for two and a half years. The results were not at all what they expected. You see, bacteria have two ways of storing DNA. They have their primary genome, which contains all sorts of genetic information. However, they also have small, circular strands of DNA called plasmids. An important difference between a bacterium’s primary DNA and its plasmids is that a bacterium can transfer plasmids to other bacteria. It cannot do so with its primary genome.

Because of this distinction, plasmids are generally thought to be “accessory” DNA. They contain lots of nice information, but since they are not a part of the bacterium’s primary genome, they are considered non-essential components. Since copying a plasmid each time the bacterium reproduces takes energy, it is assumed that bacteria get rid of plasmids that they aren’t using.

Well, it turns out that most known genes that confer antibiotic resistance to bacteria are found on plasmids. Since biologists assume that plasmids which aren’t used are lost after a few generations, it was assumed that if you get rid of antibiotics, a bacterial population would get rid of the plasmids that contained genes for antibiotic resistance in just a few generations. It turns out that they were wrong.

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Certainty and Science Do Not Go Together!

Dr. Daniel Botkin holds a PhD in ecology and is currently Professor Emeritus in the Department of Ecology, Evolution, and Marine Biology at the University of California, Santa Barbara. He is best known for his books about nature, and has been called “one of the preeminent ecologists of the 20th century.” His website has a lot of good material, including an excellent FAQ regarding global warming.

The reason I am blogging about Dr. Botkin is that he authored a fantastic article in the December 2, 2011 issue of the Wall Street Journal. The article starts with an incredibly unscientific quote which comes (ironically enough) from NASA senior scientist Michael J. Mumma:

Based on evidence, what we do have is, unequivocally, the conditions for the emergence of life were present on Mars—period, end of story.

This kind of statement might excite people, but it does nothing to promote science. In fact, it does quite the opposite. As Dr. Botkin masterfully points out in his article, the phrase “period, end of story” should never be uttered by anyone who is trying to be scientific. The fact is that in science, we never have the end of the story. New information comes in constantly, and sometimes, it overturns old ideas, despite the fact that those ideas might be accepted by virtually every scientist on the planet. As the title of Dr. Botkin’s article correctly proclaims, absolute certainty is not scientific.

Dr. Botkin goes on to discuss how global warming advocates hurt their cause by making statements with absolute certainty, and I agree with his assessment. As I read his article, however, I couldn’t help but think about the hypothesis of evolution.

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Another Goldilocks Planet?

kepler22b — An artist's rendering of Kepler 22b.
NASA image in the public domain.

More than a year ago, I discussed a planet named Gliese 581g. It was hailed as a “Goldilocks planet,” which means it is not too far away from its star and not too close to its star. Instead, it is at just the right distance, allowing it to receive the right amount of energy from the star so that stays warm enough to support life. Unfortunately, it’s not even clear that the planet really exists. One team of astronomers is confident that it does exist, but another team is confident that it does not. The latest analysis that I have seen adds more evidence to the “does not exist” side of the debate.

Well, the Kepler project has found another Goldilocks planet. I blogged about the Kepler project just a few days ago. It is a project designed to find planets that are roughly the same size as earth. They have found many, many such planets, and one of them, currently called Kepler 22b, is about 2.4 times the size of earth. What makes it special, however, is that it orbits a star similar to the sun, and it orbits that star at a distance which would allow it to receive just the right amount of energy to keep it warm enough to support life. Unlike Gliese 581g, there seems to be no doubt that the planet exists.

The popular media is abuzz with the news, and as usual, they aren’t being very accurate in their reporting. For example, here is how a space.com writer tells the story:

Kepler-22b’s radius is 2.4 times that of Earth, and the two planets have roughly similar temperatures.

Such a statement is nonsense, given what the Kepler team actually discovered.

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Life Isn’t All That Special?

Dr. Seth Shostak has a B.S. in physics from Princeton and a PhD in astronomy from the California Institute of Technology. Obviously, then, he knows a thing or two about astronomy. His original research started out using radio telescopes to measure the motion of distant galaxies, but for quite some time now, he has been involved in the search for extraterrestrial intelligence (SETI). He is currently the senior astronomer at the SETI institute.

In a recent report, CNN interviewed him to lead off a discussion about the possibility of extraterrestrial life. Here’s what he said:

…one thing that strikes you is that every time we learn something new about the universe, what we learn is that our situation doesn’t seem to be all that special, and that suggests that life is not all that special, either.

When I heard that statement, the first thing I wondered was, “How can such a well-educated astronomer say something that absurd?” Really? Our situation isn’t all that special? We live on a special planet that orbits a special star (at just the right distance) that resides in a special part of the galaxy. Yet our situation isn’t all that special?

And then there’s the last part of the statement. Life isn’t all that special? Really? Even with all our technology, we can’t come close to making it. Indeed, single-celled organisms can stitch DNA together better than we can. Despite a lot of looking, we haven’t found life anywhere else in the universe. Nevertheless, according to Dr. Shostak, it isn’t all that special.

I was hoping that the rest of the video would explain how in the world anyone could consider such a statement to be even remotely reasonable. However, it never did.

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