COLLEGE STATION, TEXAS — They are Big Bertha and Tiny Tina, a couple of piglets.
They may look and act differently (hence, their names), but these oinkers are identical. They are the newest cloned animals from Texas A&M University, which - with their births - leads the academic pack in the number of species cloned. And the fact that animals with the exact same genes can be different sizes and have different character traits may be just the first of many things that scientists hope can be learned from these little pigs.
This latest cloning project - and the wealth of information scientists hope it will provide - is just one of the many such animal-cloning experiments under way. Even as the human-cloning debate has dominated headlines and congressional hearings, scientists have cloned everything from mice to lambs to bulls.
And it is in the pens of these cloned animals - rather than the theoretical realm - where both the advances and problems of cloning are being played out.
After the 1996 birth of Dolly the sheep, the first cloned animal, the technology has been galloping along. There are now cows and goats that produce more milk and tastier meat, bulls able to resist disease, and pigs that can act as organ donors.
And this is only the beginning, say cloning supporters. For instance, breeding disease-resistant cows could save people's lives in third-world countries. And by cloning endangered species, animals such as the Atwater prairie chicken and desert bighorn sheep could be saved from extinction.
"You could repopulate the world [with an endangered species] in a matter of a couple of years," says H. Richard Adams, dean of Texas A&M's College of Veterinary Medicine. "Cloning is not a trivial pursuit.... We're trying to improve life for people here on earth."
Dr. Adams is quick to defend his school's program and to dismiss cloning's sensational aspects.
The school has come under criticism for its "Missyplicity" project, in which the owners of a dog are spending $3.7 million to have the pet cloned.
In addition to such moral controversies, opponents say there are still too many physical problems associated with animal cloning, such as deformities and high death rates during gestation. A recent article published in the journal Science, for instance, noted that researchers have found that apparently normal cloned animals develop abnormalities later in life.
But so far, so good with the health of Second Chance, a 1,000-pound Brahma bull born in Texas in June of 1998. He is being carefully watched because his donor, Chance, at the age of 21, was the oldest animal ever cloned.
The owners, Ralph and Sandra Fisher, had a special attachment to Chance, a favorite with kids at rodeos and county fairs and who appeared in several movies. One look at his clone, and the Fishers were convinced their old friend was still alive.
"This is the same animal back again. This is not a son or a twin brother," says Mrs. Fisher. "It's him."
Second Chance is the spitting image of Chance. And as for personality, say the Fishers, the two are identical. For example, Chance's favorite spot was in the front yard, just outside the kitchen window.
"The day we brought Second Chance home, he laid in the same exact spot. And the first time he saw Ralph, he loped across this pasture toward him, licking his face and his boots," says Sandra Fisher. "I'm a little hesitant to say he has memory, but he has the same instincts. Let me put it like this: Given the same problem, Chance and Second Chance would figure it out the same way."
Studying questions such as the cognitive ability and behavior of clones is of major importance, but it's hard to draw conclusions just yet, scientists say. There are simply not enough clones in the world to make valid comparisons.
That's why A&M scientists are so excited about their new piglets. Unlike cloned cattle and sheep, which produce only one offspring at a time, the litter of pigs provide scientists a chance to study several clones at once.
Consider for a moment that Bertha is roughly 40 percent larger and more aggressive than Tina, the nervous runt. Exact same genes, totally different animals.
"We're seeing some pretty drastic differences in the body weight and behavior," says Jorge Piedrahita, who heads the pig-cloning project at A&M. "What that tells us is that small differences in environment can cause large differences in personality."
Last month, Dr. Piedrahita and his crew started working with the piglets, testing memory and pattern recognition with the help of treats. The answers they get could offer more insight into the nature vs. nurture debate.
But with all that scientists are learning from cloning animals, many of those same scientists draw the line at cloning humans.
"We still don't know enough about cloning," says James Womack, director of the Center for Animal Biotechnology and Genomics at Texas A&M. "It would be foolish to attempt it with our current state of knowledge."
For instance, there is still a very low success rate for cattle. And of the few cloned calves that even make it to birth, many don't live long.
"There is a lot of trial and error right now," says Dr. Womack. "And as a society, we are not prepared for that error in humans.