Molecular biologist Peter Savolainen

Molecular biologist Peter Savolainen of the Royal Institute of Technology in Stockholm, Sweden, and his colleagues have studied the origins of domestic dogs using hair samples and mitochondrial DNA. Mitochondrial DNA is found outside the nucleus of cells in small bodies called mitochondria, which provide energy to cells. Unlike regular DNA, they are passed on only from mother to child. Over successive generations, mutations will build up in the mitochondrial sequences, and so by studying the variability of mitochondrial DNA in various individuals, scientists can construct trees (called phylogenetic trees) that illustrate the genetic relationships of the individuals, and give an approximation of when they branched off from a common ancestor; more variability means a more ancient origin.

In a paper published in November 2002, the researchers revealed the results of mitochondrial DNA analysis of 654 domestic dogs representing domesticated dogs from Asia, Europe, Africa, and arctic regions of North America. The greatest differences in the sequences turned up in samples from East Asia, which meant dogs had been domesticated there the longest. The domestic dog, Savolainen concluded, probably evolved in East Asia-perhaps as recently as 15,000 years ago-spread across Asia and Europe, and then traveled to the New World with migrating groups of humans.

Q: Why were you interested in dog genetics in the first place?

It started in 1993 when I did my Master’s thesis work on human DNA analysis at the government forensic lab in Sweden. I was setting up the first analysis in Sweden for that. People there thought that they’d like to have some dog samples analyzed for forensic purposes, because there had been some important murders in Sweden that were unsolved, and one of the few clues were some dog hairs on the corpses. It was two murders and the police wanted to know if it could be the same murderer. That was the start of my Ph.D. studies. It was a cooperation between my school and the forensic lab. I set up a method for analyzing dog hairs. This was the first analysis, I believe, of any animal sample ever done.

Q: Did it work?

Yes, it worked. It looked like the hairs had come from the same dog. A few suspects owned dogs, and we tested the dogs, but they were all excluded. Nothing more came out of it until just two years ago, when the murderer was caught for some other reason; however, the dog was dead and buried so we couldn’t check its DNA. That is how it started.

To do this kind of forensic analysis, you need a database. You are looking at a certain region of DNA and compare that between individuals and hopefully you find different types so you can differentiate between individuals. We were looking at mitochondrial DNA, so we were looking at what had been done before on mitochondrial DNA in dogs. But nobody had done anything, which surprised us. So then we had to build up our own database on dog mitochondrial DNA. We did a small database of 100 dogs from the normal Swedish dog population.

Molecular biologist Peter Savolainen

Q: Why focus on mitochondrial DNA?

Because we were looking at hairs. Normally, nuclear DNA works very badly with hairs, so you have to go to mitochondrial DNA. Nuclear DNA is good because it can give you a definite identification and you can’t get that with mitochondrial DNA, but it gives you something.

Q: Why did you expand that to look at the evolution of dogs?

At that time I had no knowledge at all of population genetics, but just looking at the data, I thought there was more we could do with this, that we could say something about dog history and origin. When I did my research for the first forensic study, I tried to look in the literature for the history of dogs so I would know what DNA variation to expect. I read a lot of books about the history of dogs, but got more and more frustrated. There were meters on the bookshelf written on the history of dogs, but it was based on almost no hard facts. There was also bad information from archaeology, so I saw that we needed to do this for the community. At that point I started to try to collect samples on a larger scale, from around the world.

Q: How did you decide which dog breeds to look at?

What I learned through my contacts around the world, collecting dog samples, was that the concept of dog breeds was something European, in Europe and North America. In other parts of the world, you don’t necessarily have “breeds,” and covering breeds was not of direct interest to me. What I was after was as good a sample as possible from each part of the world, of what could be supposed to be the original dog population in each part of the world, so that I could compare these samples with each other.

Q: Does your data show which dogs are the most ancient?

My data is only about the first origin of dogs-where and when they evolved and in how many different places. We could show that it probably happened only once and that it happened somewhere in East Asia. All of the types of “ancient” dogs have only one single common origin from the wolf.

Q: What would have been special about East Asia that might have caused this to happen?

I don’t know so much about that, but one thing is that southern Asian wolves are generally smaller than north Asian and European and North American wolves, so perhaps they were easier to handle. There have been theories that the dog would have come from somewhere in the Middle East, because these wolves are smaller, but wolves are approximately the same size across south Asia, across India and southern China. I can’t say that I have any good idea why it happened just there. Perhaps it was just chance.

Q: Did the results surprise you?

I am open-minded. Many people thought that the dog should have come from the Middle East, for example, but that was based on very little fact. I could have expected more or less anything.

Q: Have you pinned down the date of domestication any more specifically?

With the data we have, we can’t pin down a certain date. It is impossible. However, we have more data coming, and we believe that we will be able to give a better date. With DNA data, you can never get a very specific date because the errors in the measurements are so big. You can only say something plus or minus 5,000 years, for example. So for the exact dating you have to rely on the archaeological data, and that tells us that the dog seems to have evolved 10 to 15,000 years ago, and what we can say is that the DNA data doesn’t contradict that.

Q: Have you expanded the study?

We are working on a new study and have more samples from everywhere, which means that we can say more detailed things.

Q: How many more dogs?

In the old study we had 654 dogs, from our own work and from the literature, and now we are working with 1500 dogs, with samples collected worldwide. Because we have a more complete sample, I am more certain about the results than I was in 2002.

Q: Not everyone agrees with you….

No, but that’s because they haven’t seen the new data. I think it will be convincing. There can always be disagreement, but now we can be more certain that the data are correct. We should be publishing it this year.

Q: Do you plan on additional studies with more samples?

We have already gotten samples from dogs from around the world so we can do more specialized analysis of, for example, African dogs, so we can say in more detail how and when African dogs came to Africa. I have tried to work from the basic questions up to the more specialized ones; I started with where and when the dog originated, and now I want to answer how did the dog spread from this East Asian origin to other parts of the world, and then also how the first different types of dogs evolved. We have started to look at that, and we are also trying to get a good sample of every kind of breed.

Q: Will you be using the database for forensic purposes?

I haven’t done any forensic cases for a few years because I have been focusing on dog history. But we could use our population data to say that this type that we found in a specific sample is so common in the dog population, we have found it in so-many German Shepherds but not in any poodles, so the hair probably comes not from a poodle but from a German Shepherd. The more data we have the better answers we can give to the police.

Q: Do you plan to study the domestication of other animals?

If nobody else does cats, I guess I will have to do it. I have done a few studies on other animals — for example, I was involved in a Chinese study on the origin of the yak — and we are planning to take a look at the domestication of horses also. But I think we have a lot to do for at least the next five years with dogs.

While his prolific mating is a clear sign of the king’s success, this unique gorilla’s extensive family tree grew out of tragic circumstances.

At first, daily life for Titus was routine. He was a member of a stable group of happy individuals. The group even surprisingly allowed a young outsider to join them, which is very unusual among gorilla groups. Normally they will not tolerate outsiders. Tragedy struck when Titus’s father, “Uncle Bert,” was murdered by poachers. The young outsider, Beetsme, who had become close with Titus, could sense an opportunity. He exhibited classic takeover behavior and grew aggressive toward the females of the group. In a skirmish with Titus’s mother, “Flossie,” Beetsme struck her infant, killing it. Flossie and Cleo, Titus’s sister, subsequently deserted the group, leaving young Titus orphaned and abandoned.

For a time, Titus, Beetsme, and the other remaining young males formed a group of their own. But when another group disbanded, females from that group joined them, and Beetsme became the leader of the new family group. He drove away every other male, except for Titus, who he allowed to stay, possibly to help keep the group safe from outsiders. He had succeeded in eliminating competitors for what were now his females — or so he thought.

This image shows some of the offspring Titus is known to have sired. Images are not available of all of them, as some may have died or left the area. Click to enlarge.

Beetsme was unaware that Papoose, the dominant female, was growing rather fond of his young companion, Titus. Even researcher Martha Robbins agreed with Papoose’s judgment, joking in The Gorilla King that in her own opinion Titus was the more handsome of the two. Behind Beetsme’s back, Papoose was mating with Titus. It was the beginning of an impressive dynasty.

In the course of her research, Robbins began a series of paternity tests to see who was having the most reproductive success. The tests proved that Titus had fathered several babies with Papoose, among them, Pasika, Bukima, Turakora, and Kuryama (the male whose challenges to Titus’s reign are documented in The Gorilla King).

All told, researchers at Karisoke believe that Titus has sired over 20 babies, though they are still completing DNA tests to make sure. They do know beyond a doubt, however, that he has fathered at least 13 — still more than any other known mountain gorilla.

Not too bad for a gorilla who had such enormous odds to overcome.

Whooping cranes learn survival lessons from human surrogate parents on NATURE’s Flight School.

At five-feet tall, with a wing span of nearly 8 feet, whooping cranes are among the largest and most beautiful birds of North America. But hunting and other forms of human encroachment drove them to the very edge of extinction in the mid-20th century, when the head count for the last known flock plummeted to an all-time low of just 15. Legal protection, conservation measures, and artificial breeding programs have slowly lifted the number of whoopers to more than 400 today, of which nearly 300 are in the wild. But those are still dangerously low figures.

Enter Operation Migration — a group of scientists from the Patuxent Wildlife Research Center in Maryland, the International Crane Foundation in Wisconsin, and other conservation groups. To help ensure the survival of these endangered birds, Operation Migration maintains an artificial breeding program that prepares chicks for adulthood. Disguising their human appearance with whooping crane costumes, researchers meticulously train the chicks for flight. Using ultralight aircrafts, the scientists then lead them on their inaugural migration — covering more than 1,200 miles. The scientists are hoping that their experiment will enable the birds to grow up as normal adult cranes and successfully breed.

Follow the whooping cranes’ migration and share the excitement, perils and, in some cases, the heartbreak of the scientists of Operation Migration in Flight School.

To order a copy of Flight School, please visit the NATURE Shop.

Online content for Flight School was originally posted April 2004.

In 1923, Psychobiologist Robert Yerkes purchased two young chimps from a zoo for his own behavioral studies. These two chimps, named Chim and Panzee, would be the first of thousands to be used for the sake of scientific research in the United States. And while internationally, the use of chimps in research has declined over the last decade, in the US, chimps continue to be used in biomedical research. According to the Humane Society of the US, approximately 1300 chimpanzees live in 11 laboratories around the US-making the US chimp population the largest collective chimpanzee colony for biomedical research in the world.

It is a harsh irony that what makes chimps so like humans, makes them such sought-after research subjects. Sharing so much of our biological makeup (99% of DNA, in fact), chimps have been used in the study of infectious diseases, gene therapy, vaccine development, reproduction, language, behavior, even anatomy.

Though they can catch or be infected by nearly all known human infectious diseases, Hepatitis research remains the largest area of chimpanzee use in the US. Nearly one third of chimp research dollars in 2003 and 2004 went to Hepatitis studies. The research has virtually eradicated Hepatitis B and C infections acquired through blood transfusions, though critics of chimp research say the first Hepatitis B vaccine was made from the blood of infected humans.

Introduction What are the alternatives for medical research? Slideshow Interview with Gloria Grow, founder Fauna Sanctuary Caring for Captive Chimps Q and A with the filmmaker Video Links and books Download Wallpaper For Educators In the 1980s, during the height of the HIV and AIDS outbreak, chimps were aggressively bred as subjects for studies of the disease. But this breeding campaign would soon result in thousands of surplus chimps when they were found to be poor models – never developing full-blown AIDS.

Critics of chimp research argue that the case of HIV is not an isolated case of scientific indiscretion. Even in the case of Hepatitis, chimps respond differently from humans. Chimps infected with Hepatitis B will not become sick while humans exhibit traditional symptoms of liver disease. And chimps infected with Hepatitis C will not develop cirrhosis of the liver or liver cancer, though humans will. And in fact, with regard to drug development, 70% of drugs that have tested safe in nonhuman primates are known to be harmful to the human fetus.

Fortunately, science presents some possible solutions. In July of 2005, Hepatitis C researchers reported a breakthrough in the technology to grow the virus entirely in cell culture. And the vaccine for this disease is now made from bacterial culture.

Using human volunteers with a specific illness in clinical trials for new drugs is, say animal research critics, a more accurate and humane alternative to testing drugs in animals like chimps. Today, a great deal of Hepatitis research is successfully carried out through observation and clinical trials on humans with the disease. The perceived risks of participating in trails is getting smaller. In one form of human clinical trial, called micro dosing, human volunteers are given minute doses of an experimental drug too small to even have negative effects on the body. The physiological effects of the drug are then extrapolated using high tech laboratory equipment like a mass spectrometer. This method can be very effective, and was used during clinical trials for drugs to treat AIDS and HIV.

Unfortunately, human studies are expensive to undertake and are limited by a shortage of human volunteers. While it may be some time before they replace testing in animals such as chimps, they can still provide valuable clues as to how different classes of substances elicit their effects, and thus reduce the need for animal testing. They can also provide a much-needed framework for the development of alternatives based on human or animal tissue and cell systems.

In in-vitro testing on human cell cultures and tissues has become an emerging alternative. Conducted on living cells in containers such as a test tube or Petri dish, the method tests the toxicity of substances, essentially “in bulk,” meaning that large numbers of compounds can be screened rapidly and simultaneously in numerous cell lines, rather than in one individual animal. The method is not only much faster than animal tests, it is also more accurate since human cell lines are used. In-vitro studies on human cells and tissues have made possible the investigation of the immune-stimulating effects of potential vaccines and the analysis of HIV transmission.

New research tools and equipment can also provide alternatives to testing in animals such as chimps. By providing scientists with a clearer and more precise understanding of the physiology of disease(s), scientists can monitor actual patients of the disease they are studying at the cellular level. Techniques such as paper chromatography, radioimmunoassay, genetic engineering polymerase chain reaction, and positron emission tomography have all advanced our understanding of biomedical knowledge. Positive emission tomography, for example, can be used to safely and noninvasively examine the activated lymph nodes and spleens of patients given vaccines or to monitor viral infections in a temporal and spatial manner.

Of course, the genomic revolution has equipped scientists with unparalleled tools for engineering “personalized medicine.” Knowing the correlations between human disease and specific genes could allow doctors to prescribe the right drug at the right dose for the right person, based on unique variations in their DNA- not on the DNA of a chimp, or even a mouse.

While some of these techniques are years away, others are already here and in place. But as more viable humane options are uncovered, perhaps testing our drugs on chimps will seem less necessary and less ethical. And we can finally release chimps from their role as research subjects in our society.

It doesn’t take much imagination to see the similarities between a human child and an adult. But as NATURE’s The Body Changers shows, in other animals, the young may bear little resemblance to the grownups. It’s hard to see a butterfly within the fuzzy form of a caterpillar, for instance, or a sleek dragonfly in the squat features of its aquatic larva. Indeed, early naturalists sometimes believed that the larva of some animals, such as eels and frogs, were a totally separate species from the adults, because they looked so different.

Today, however, we realize that many creatures undergo startling transformations as they mature. But we are just beginning to understand the genetic blueprints that guide these changes.

Genes exert a powerful influence on body changes.

Over the last few decades, researchers have been homing in on the chunks of DNA, called genes, that hold the instructions that tell cells when, and where, to grow. Some genes, or sets of genes, for instance, control where limbs or wings sprout. Others determine the top and bottom of an organism, or its head and tail. By turning these genes on and off in sequence, organisms guide their development from just a single cell to a creature made up of billions of specialized cells. Eye cells, for instance, look and behave very differently from skin cells, though both are children of exactly the same original cell.

To create such differences, some genes exert especially powerful control over cells when turned on. In 1995, for instance, Swiss biologists showed that inserting and turning on a few related genes in fruit fly cells could cause surplus eyes to sprout virtually anywhere: on wings, legs, and even antennae. Researchers manipulating other genes have caused salamanders to grow legs in the oddest places, or not grow them at all. And turning off some genes by blocking their action can prevent some animals from maturing at all, leaving them permanently stuck in their larval forms. Such research is helping scientists understand genetic diseases, and may eventually lead to new treatments.

The research is also teaching us something about evolution. Researchers have discovered that many of these key developmental genes — which have been given whimsical names such as “sonic hedgehog” and “superfly eye” — appear in many animals, from insects to humans. Over time, they have been passed along as one species has transformed slowly into another.

But different animals may use similar genes in different ways. A gene that prompts an arm or a leg to bud off from a main body in a mammal, for instance, might prompt a sharp spine to bud off on the shell of a sea urchin. Despite the very different structures involved, the underlying genetic instructions are the same, suggesting that the two animals shared a common ancestor long ago. “A lot of evolution represents the commandeering of genes from one form to another,” David Jablonski, a paleobiologist at the University of Chicago, told the magazine SCIENCE in 1999.

Gene hunters are far from finding — or understanding — the millions of genes that play key roles in body changes. It is already clear, scientists say, that genes allow for a lot of creativity in organism design. It’s like having a set of building blocks you can snap together in an infinite variety of ways. According to one researcher: If you don’t like one design, you can change it.