D. Andrew Merriwether ambles into his lab wearing a green T-shirt, a weathered Binghamton University ball cap and a graying ponytail. He ignores the birthday cake on the bench (chocolate frosting with peanut butter cups) and pulls up a stool.

He has been doing some fieldwork, he says. For this particular molecular anthropologist, that means he was actually in the field — with his alpaca.

He’s looking for genetic links that cause choanal atresia — a disorder found in both the alpaca and humans in which tissue or bone blocks nasal passages. It’s frequently fatal among the alpaca because babies with the condition can’t breathe while nursing.

Choanal atresia has perhaps 20 causes, Merriwether says. Only a couple may be genetic, but understanding the genetics may lead to strategies for prevention or early diagnosis in humans.

That’s a small part of how the alpaca play into his research. “They’re just so neat: curious, quick, smart,” he says. “They survive on almost nothing.”

As a species domesticated by early South American populations, they reflect the culture of the people about whom Merriwether did his dissertation 20 years ago. “For the poorest people of South America, it’s their only source of cash income,” he says. Like those people, Merriwether and his wife shear their alpaca herd.

Genetically, the alpaca had to adapt to life in the 13,000-foot altitudes of the Andes just as people did, says Professor Ralph Garruto, a National Academy of Sciences member whose presence at Binghamton drew Merriwether to the faculty in 2003. How they did that is a question with implications for cultures across the world.

“How do people who are genetically different adapt to the same stressors?” Garruto asks. Women in most parts of the world can’t carry a fetus to term above 10,000 feet, but the people of the Andes do it routinely — as do the alpaca. “All the changes in the alpaca help us see the mechanism in that animal and whether there are parallels in humans. We’re talking survivability and functionality of human beings.”

The alpaca aren’t Merriwether’s sole focus. About a third of his research lies in Melanesia, with the peoples of New Guinea and the Bismarck Archipelago. He has many of the same questions he had about the South American cultures that got him into molecular anthropology in the first place: How did they get there? How long ago? How have they adapted?

“Almost every question I am interested in,” he notes, “has DNA as a way of answering it.”

Binghamton University biologist Heather Fiumera thinks that some of those health problems may lie in the fact that mitochondrial function requires the cooperation of two different genomes. Every human inherits two genomes: one in the cell’s nucleus, which is a mix of mom and dad’s DNA, and a different one in the mitochondria (the cell’s powerhouse), which contains a replica of mom’s mitochondrial DNA. “It may be that some combinations of mitochondrial and nuclear genomes work together more efficiently than others,” Fiumera says. “While mutations in either genome may affect mitochondrial function, they don’t explain the whole story. You might inherit a mitochondrial genome that helps you become a world-class marathon runner, but your brother” — who would have the exact same mitochondrial genome as you — “might not be as successful, even with the same training.” Similarly, a mitochondrial mutation may cause a severe metabolic disorder in one sibling, but mild symptoms in another, because of how the mitochondrial mutation interacts with their different nuclear DNAs.

Fiumera and her colleagues received a $1.25 million award from the National Institutes of Health (NIH) to explore the importance of these genetic interactions. The five-year grant will help Fiumera scale up the studies she is already doing in yeast. “We’re swapping mitochondrial genomes and seeing if it affects how our yeasts grow,” Fiumera says. “And we are finding that it really matters.”

Kristi Montooth, a biologist at the University of Indiana, says the work may help to illuminate why metabolic diseases are so variable and unpredictable. “There are mutations in mitochondrial genomes that, on their own, don’t have a negative effect,” she says. “But brought together with certain nuclear genomes, there’s a synergistic effect that causes them to function badly.”

The problem goes back to the evolutionary origins of the mitochondrion. Scientists believe that a mitochondrion has its own DNA because it was once a free-living bacterium that was engulfed by another cell. But instead of becoming dinner, the mitochondrion was co-opted to provide energy for its predator. The two cells managed to work together and, over time, became dependent upon one another. Mitochondria have inserted some of their genes into the nucleus, and the nucleus uses protein messengers to control how much energy the mitochondrion produces and how it does its job. It may be that the two genomes are still co-evolving and still learning the best ways to live together peacefully.

“Heather’s exploiting a lot of the genetic and genomic tools that yeast offers to take this to the next level,” says David Rand, who studies the coevolution of nuclear and mitochondrial genomes at Brown University. “The ability for Heather’s experiment to track down the interactions is going to be quite powerful.”

Yeast is a single-celled fungus with some powerful genetic tools that allow Fiumera to mix and match mitochondrial and nuclear genomes. Are there special combinations that allow better mitochondrial performance? Does “strain A” work better with mitochondrion 1 while “strain B” works better with mitochondrion 2? Fiumera will decide which combinations thrive best by subjecting her yeasts to a variety of unpleasant environments — including heat stress, oxidative stress and low-nutrient conditions — and measuring how well the mito-nuclear hybrid strains grow.

Montooth says previous studies have focused on swapping mitochondria between different species of yeast. But by looking at the variation within just one species and exploring how that variation relates to dysfunction, Fiumera’s work is more relevant for studying human disease.

So far, Fiumera’s preliminary studies have shown that the mitochondrial-nuclear interactions are responsible for as much as 20 percent of the differences in growth rates between strains. “That’s huge,” she says. Until now, Fiumera and her team have managed to look at the interactions among only a handful of strains. The NIH grant will help to buy laboratory equipment that will measure growth rates in about 200 samples at once, helping Fiumera to test hundreds of different yeast strains. She predicts they will collect more than 10,000 growth rates in just the initial phase of the project.

The second part of the experiment will be to map the genes involved in determining whether a combination is effective or ineffective. Fiumera says she’d eventually like to see whether beneficial combinations are more common in wild yeast populations; if mitochondrial-nuclear interactions are as important as biologists expect, it is likely that natural selection favors different combinations in different environments.

But Fiumera won’t be doing all of this work alone. “This project is a marriage between yeast genetics and population biology, and it is enhanced by my actual marriage to a population geneticist,” she jokes, referring to her husband, Binghamton biologist Anthony Fiumera, who will be collaborating on the project. Binghamton computer scientist Kenneth Chiu will lend his expertise to help the biologists parse through huge data sets.

Since energy production is so vital to a cell’s functioning, mitochondrial genes and machinery tend to be highly similar in organisms as far flung as yeast and humans. That allows Fiumera to hope that one day her research will be used to devise treatments for people who are suffering from debilitating metabolic disorders.

“You have to understand the mechanism behind a problem,” she says, “before you can fix the problem.”

Now it’s possible to boost the odds of getting a winner with a simple genetic test. ThoroughGen, founded by Binghamton biologist Steven Tammariello, performs genetic testing on horses. The company is one of four competing in the equine genetic-testing business.

ThoroughGen offers a basic three-gene test for Thoroughbreds at a cost of $175. It screens for one gene that is vital to energy production and two tied to muscle function. Energy production is linked to stamina, muscle twitch to speed. For an added fee, the company will check for additional genes associated with behavior and soundness, including bone density and heart size. The behavior genes indicate whether a horse is likely to be trainable, and soundness is a critical concern since some racehorses are prone to breakdown.

“This is just the tip of the iceberg,” says Tammariello, noting that the horse has some 21,000 genes.

The business really takes off at horse sales, where potential buyers want to find out if they’re getting a horse with promise. ThoroughGen and its partner, Performance Genetics, deliver results overnight, a critical consideration at a horse sale where buyers have to make up their minds quickly. Tammariello carts a portable testing device to sales. “If I receive a sample by 4 p.m., I can give clients results the next morning,” he says. Just one strand of hair from the horse’s mane is all he needs.

The field is so new that it’s still fighting pockets of resistance. “If someone comes to a sale expecting to sell their horse for $400,000, I can understand why they would be nervous that we might say the horse has a flaw,” Tammariello says. Still, for many breeders in the Thoroughbred industry, genetic testing is the future.

And it’s the future for other breeds of horses as well, not just the racers. “If buyers want to find out what makes the strongest Belgians, we can do that,” Tammariello says. “I’ve been contacted by an Argentinean group that wants to figure out which gene variants are found in a top polo pony. We can look at any variation that anybody wants to look at, in any breed of horse.”

Of course, the tests aren’t foolproof. The right genes don’t guarantee a winner; the wrong genes don’t guarantee a loser. But the tests do boost the odds of picking fast horses and avoiding slow ones. “Only a small percentage of horses overcome genetic flaws,” Tammariello says.

Tammariello grew up near Erie, Pa. His father, a geneticist, taught biology at nearby Edinboro University of Pennsylvania. When he had time, young Tammariello would watch Thoroughbred races at Erie’s Commodore Downs.

Tammariello earned a Ph.D. at Ohio State, where he studied molecular genetics, and did postdoctoral work at the University of Kentucky, where he looked at the molecular regulation of Alzheimer’s disease. Afterward, he joined Binghamton’s faculty, focusing on research in Parkinson’s disease and related neurodegenerative illnesses. “I wasn’t trained as a horse geneticist,” he says. “But I’ve always been a fan of horse racing, and my wife and I have owned partial interest in nine horses.”

One day Tammariello wondered if there was a way to look at a horse genetically in order to get a predictor of its racing potential. “I assumed that someone would have already done genetic testing on Thoroughbreds,” he says. Yet when he did an Internet search to find genetic-testing services, he came up with none.

So Tammariello, with help from a small group of researchers, began to look for Thoroughbred genes linked to athleticism. “If we found a gene that was important to athleticism in greyhounds or humans, we looked to see if we could find the same genes in the horse,” he says. Gradually, they found some.

They also compared breeds of horses to one another. “We looked at genes that were important to muscle twitch and energy in breeds from Belgian draft horses to Thoroughbreds,” Tammariello says. “We found a variant in draft horses that was also found in slow Thoroughbreds. A lot of our clients have brood mares and they want to know whether they carry the variant for slower muscle twitch. Slower twitch is useful for muscular power, but not for speed. We can test a whole bunch of Thoroughbreds and predict which ones aren’t going to make it to the track.”

This gives breeders a new option. They can continue to breed top horses to top horses, or they can use the tests to figure out which horses might make the best breeding match. That should produce more good horses, though not necessarily faster times. “Honestly, I don’t think speeds will get faster,” Tammariello says. “I tell my clients that this is not a way to breed superhorses. What we are trying to do is decrease the number of substandard horses that are produced.”

Texas Thoroughbred breeder and veterinarian Jim Ward has used Tammariello’s services. “Genetic testing is probably going to be a game changer,” Ward says. “I’m familiar with beef cattle and dairy cattle, where they made big strides in breeding after identifying gen- etic traits. I don’t see why it couldn’t work the same in horses. The logic is good.

“If you can eliminate those horses that don’t have a chance, you’re going to save yourself a lot of money,” he adds. “Training race horses is expensive. You’ve got to do it for a year or so before someone tells you that your horse can’t run. We’re talking about $25,000 a year in training and veterinary expenses.”

There is, as you might expect, a parallel genetic testing movement for human athletes. A growing number of companies offer tests that suggest which children might excel in which sports and which aren’t likely to excel at all. But if a child proves to be a washout in sports, he or she can go onto other things. Racehorses aren’t so lucky.

“Right now, there are more Thoroughbreds produced than ever make it to the track,” Tammariello says. “In fact, about one-third of the Thoroughbreds born each year will never race. Some are not sound enough. Some are not fast enough. So there’s a whole population of horses that they don’t know what to do with.”

But by genetically testing stallions and mares, breeders may get a better idea which matches are likely to pay off. “We wanted to improve the chance of horses running well,” Tammariello says. “At the same time, we wanted to decrease this surplus of horses. If you have a good idea of what you will get, you may forgo breeding horses that have a high probability of failure as racehorses.”