Researchers at the University of Milan mixed swine sperm with the
DNA of a human gene called decay accelerating factor, or DAF, and
then used the modified sperm to fertilize pig eggs. The eggs were
implanted into sows to produce litters of pigs that carried the
human gene.

“What we obtain at high efficiency and low cost is genetically
modified pigs expressing the human protein,” said Dr. Marialuisa
Lavitrano, a University of Milan researcher and first author of
the study appearing Tuesday in the Proceedings of the National
Academy of Sciences.

Lavitrano said that 205 piglets in 20 litters were produced using
the modified sperm technique and the human genes were present in
20 to 50 percent of the young. Tests showed that the human genes
were present in the animals’ central organs and that the human
genes would be passed along to later generations of pigs.

Organs from the test animals are not ready for transplantation
into humans because there are still pig genes that would cause the
organs to be quickly rejected, said Lavitrano. But she said the
technique shows that by adding human genes to pig sperm it is
possible to develop animals with organs that will not be rejected
by the human immune system.

“They could be the starting point for new transgenesis (gene
transfer) experiments,” she said. Lavitrano said that five to
seven other pig genes will need to be silenced or replaced by
human genes before useful organs could be harvested from the
animals. “With our efficiency we think we can add the other genes
and breed the animals in about two years,” she said.
[10/21/2 – Associated Press]