Page 36 - Breeding Edge ebook

His gene editing appears successful so far, Dunham reports. In his first parent generation, “we have
really strong evidence that these fish were sterile or had greatly reduced reproductive capacity,” he said,
noting that complete adoption is never achieved in the first generation.

Significantly, most of animal-related gene editing to date doesn’t mess directly with the genomes of
humans or higher life forms. Nearly all of it involves modifying simpler life forms to improve health for
people, farm animals and wildlife, and most of it, like the PRRS remedy, targets diseases or harmful
pests.

Gene editing, in fact, portends even more direct benefits to human health. Possible herpes resistance, for
example. Nearly all adults are infected with types of herpes viruses, a group that cause cold sores,
keratitis, genital herpes, shingles and mononucleosis. The viruses can remain dormant for long periods
and then spring up. But scientists now suspect that they can use CRISPR genome editing to inactivate
herpes by attacking its genes directly within people’s virus-infected cells.

Meanwhile, gene editing is sure to spell more human medical blessings via farm animals, often
called farmaceuticals.

A few such advances, using transgenic
procedures, have already been approved,
because they offer clear benefits for
people. In 2006, for example, the biotech-
reluctant European Union (and in 2009,
the U.S.) green-lighted a breed of goat
modified to produce a human anti-clotting
protein, called antithrombin alfa, in its
milk. The protein is needed to treat people
with hereditary antithrombin deficiency, a
rare clotting disorder. Now, it can be harvested from the goat’s blood, instead of from a human donor’s
blood, the traditional source. Also, the EU and U.S. have both approved a genetically-modified chicken
that lays eggs containing an anti-cholesterol drug.

Kris Huson, communications manager for Recombinetics, explains that her company, like many other
biomedical research entities, likes to employ pigs as surrogates for developing health remedies for
people.

“Now, particularly with gene editing – and pigs share so much DNA with humans and human diseases –
they are just a superior animal model,” she said.

Her company has modified pig genomes so the animals can develop colon cancer, human heart disease,
Alzheimer’s, diabetes, and other human disorders and/or resistance to such disorders, giving researchers
targets to pursue human health remedies.

Mice have long been used as a model for human health research, she points out. “But it is a big stretch to
go from a mouse heart to a human heart,” she says, so pigs, whose organ sizes are similar to human
ones, have become highly desired for clinical research.

“The next step is using pigs as an ‘oincubator,’ we are calling it, -- sort of an incubator -- to grow
human tissue cells and organs in the context of a pig.” She asks: “Could we one day grow organs
for patients: a cornea, lung tissue, hepatocytes, pancreas cells?”

34 www.Agri-Pulse.com