Our world-class clones (no bull)

On the global stage, the contribution of Australia and New Zealand to the livestock cloning arena is world class, which is only natural given the region's strong tradition in agriculture.

In Australia the field is led by groups including the Monash Institute of Reproduction and Development in collaboration with Genetics Australia, Clone International, which has a partnership with Geron in the United States, and the South Australian Research and Development Institute (SARDI), which is internationally renowned for its sheep cloning efforts.

Across the Tasman in New Zealand, AgResearch is regarded as among the most successful cattle cloning groups in the world.

The potential of cloning as a valid livestock reproduction technology took its first major step into reality with the creation of Dolly the sheep in 1997 through somatic cell nuclear transfer. The technique, which involves an adult donor cell being fused with an egg that has had its nucleus emptied of chromosomal DNA to create an embryo, fired the imaginations of scientists worldwide.

For those in the animal agriculture sphere, here was a technology that could possibly enable prize stock to be recreated in perpetuity. It was a technology that had the potential to exponentially increase the semen output of genetically superior bulls by simply allowing breeders to make endless copies.

And when combined with genetic tinkering to improve qualities such as wool, meat and milk output, it presented the chance to clone perfect production animals on a large scale and quickly.

But despite the strides made since Dolly first hit the headlines, scientists concede serious commercial returns from livestock cloning still appear somewhere off on the horizon.

Clone International this year sold two of its cloned elite bulls for about $400,000, but most in the field agree that the real commercial gain will come only once the scientific fundamentals of the technology are understood.

While several international groups have now validated the fact that somatic cell nuclear transfer works, they say Nobel prizes are waiting for the molecular biologists who can get to the bottom of how and why it works.

According to Clone International's CEO, Dr Richard Fry, cloning is far from a new concept.

Fry says scientists had been splitting embryos and cloning eight cell embryos for years. What was novel, he says, was that with somatic cell cloning, companies like his could make genetically identical copies of animals once it was realised they were superior.

For Clone International, which in collaboration with Australia's largest private artificial breeding company RAB is cloning dairy bulls for export, it could take five years before a prize bull is identified.

Clone International, through Geron, holds the licence to the technology that produced Dolly and is able to apply that to cattle, sheep and horses within Australia and New Zealand.

"Our aim is to produce a copy that is genetically identical to the original animal and to put a large number of copies of animals on the ground to make their genes more available," Fry says.

The company recently sold two clones of Australia's top Holstein sire, the RAB-owned Donor, for $200,000 each in Asia.

Fry says that when one considered Donor produced 130,000 straws of semen annually at $25 each and that this was only enough to supply the local market, the commercial potential became clear.

Another application recently exploited by Clone International was the creation of the clone of another popular sire, Nuclear, who had been unable to produce semen for the past 18 months following an accident.

By creating a clone, Nuclear Alpha, demand for the prize bull's semen could again be met.

Apart from the need for more basic research, another aspect holding back cloning is poor efficiency; that is, the number of live offspring expressed as a percentage of the total number of fused embryos created.

According to a Roslin Institute review of literature, efficiency rates for nuclear transfer cloning generally hover below 6 per cent in mice, 5 per cent in cattle, 0.5 per cent in pigs, 1.7 per cent in sheep and 1.6 per cent in goats.

But the team at New Zealand's AgResearch are confounding the average cattle cloning efficiency at least, by achieving rates of up to 20 per cent - a result that effectively halves the cost of production faced by peers.

Nonetheless, a scientist with AgResearch's Reproductive Technologies Group, Dr David Wells, says even this rate is not good enough to be commercial on a large scale.

"It's still quite an inefficient process," Wells says.

"At the present one can only really use it at the top end to produce a small number of clones from elite breeding bulls. There's still a long way to go because 15 to 20 per cent of live births at term is less than half what we would expect to get following IVF, which is 45 to 50 per cent in cattle."

That's compared to 55 per cent for artificial insemination (AI) and 67 per cent for natural mating.

"AI is quite expensive and inefficient and inconvenient for farmers, and the notion is that one could generate hundreds of clones of a top ram or bull and use natural mating to replace AI and increase the dissemination of genetic gains," Wells says.

He says a novel application of the technology could be to "resurrect" beef carcasses shown to have especially tender meat. By conducting a line assessment of carcasses in an abattoir, scientists could identify those with the best meat characteristics, take a sample and recreate the animal.

Wells says that by using cloning to reduce the level of genetic variance, the result could be more uniform products for consumers. He says cloning could also be integrated into animal conservation schemes to help preserve indigenous breeds of livestock.

But he warns that the potential gains from the technology need to be balanced against the possible loss of genetic diversity among animals.

Another application being pursued by Genetics Australia in collaboration with the Monash Institute and Victorian Institute of Animal Science is the combination of transgenics and cloning. In March, the group unveiled four genetically modified calves born with an extra gene for milk protein production - a first for the Australian dairy industry.

The team, which produced Australia's first cloned cows and bull, revealed Holly, Molly, Lolly and Jolly, the result of a research project to establish technologies that would help produce more nutritious dairy products and that could bring possible medicinal benefits.

The extra gene was intended to increase the protein content in the cows' milk by as much as 15 per cent. Genetics Australia Research and Development manager and Monash Institute senior research scientist Dr Ian Lewis says the success raised hope that researchers could perhaps insert genes in animals to create human medicines - a feat that could prove a boon for third world countries.

Lewis says cloning would enable accelerated breeding of these genetically modified animals, and predicts that rather than buying semen in straws, breeders of the future could instead be purchasing cloned GM embryos.

"These products and technologies are at least 10 years away and will only come to pass if the general consumer population supports it," Lewis says. "But we need to be developing this technology because we don't want to be left behind and then have to buy it in, because that would be bad for the Australian consumer, farmer and economy."

Education is one of the reasons behind the research work at SARDI, where a livestock reproduction team led by Dr Simon Walker is examining the benefits of cloning technology in sheep.

Walker's team was the first in Australia to clone a sheep when Matilda was born in April 2001. It now has four cloned sheep.

Although Clone International holds the license to clone sheep through Geron, it has chosen not to because of the difficulties and the fact the monetary value is not on par with the dairy bulls that have become its focus.

Walker says the license had no effect on its own research work, which is focused on making the technology more efficient, getting a better understanding of the biological problems encountered by cloned animals and generating enough clones to evaluate under commercial grazing conditions.

"Our brief is to really not just develop the technology but to see if it is of value to farmers," Walker says. "Others have taken the assumption that it is of value and are pressing ahead with the commercial aspects.

"But the first thing we have to do is determine if it works well enough and what the benefits actually are for farmers, rather than trying to position ourselves in the market."

The group is examining foetal development of clones to determine why most die and why those born with defects are most commonly afflicted with defects of the urinogenital tract, particularly the kidneys.

"We have to stress that this is basic research to understand a new procedure and that sheep seem to be a problem species," Walker says.

While the group is on par with the few sheep cloning labs around the world, Walker says its work would be improved through a better understanding of the basics of nuclear reprogramming.

AgResearch's Wells agrees that the basics of the technology were the new focus for his group, too.

"We repeated the Dolly success and we're relatively efficient, but we don't understand how it is possible to clone this way," Wells says.

"We're wanting to move into the more basic biology to get a greater fundamental understanding of how it is possible to reprogram the biological clock or pattern of gene expression from a differentiated cell back to a stem cell."

But it is not only sheep and cattle that are keeping Australian scientists busy. Clone International has also begun research work in the race to be the first to clone a horse.

The local team is up against a group from Cambridge who are understood to have created cloned equine embryos.

"We have been able to grow cell lines from horses which has also enabled us, as part of our business, to put down genetic protection packages for horse insurance purposes," Fry says.

He says horses appear able to be cloned only from live tissue, and the company is creating cell banks from well-known pacer Gamalyte.

Despite the argument that animal cloning brings the science world closer to the controversy of human cloning, livestock researchers say the technology is simply a potential reproduction alternative for farmers wanting to keep their stocks at a high quality level.

Walker says the technology is simply an efficient way of distributing genes within a livestock population. "It's not about increasing genetic merit, it more about duplicating, in our case, sheep of high genetic merit," he says.

"So if you can duplicate genetically elite rams, for example, in Australia, you can sell them to more clients and at the same time provide a means of preserving a prized genotype."