Image courtesy of Dr. Gary B. Anderson, University of California
A sheep named Dolly
British scientists made world headlines in 1996 with
the cloned sheep named Dolly. Dolly was world's first cloned mammal.
Scientists say cloning sheep and other animals could lead to advances
in medical research, including cloning animals to produce human
antibodies against disease. At the same time, rapid progress in
stem cell research and genetics has raised widespread debate about
the ethnics and boundaries of science and medicine.
Mending broken hearts
Embryonic cells from mice can help mend the broken hearts of sheep.
This cross-species experiment is one more step in finding out
whether human embryonic stem cells can mend the damage done by
heart attacks. A heart attack damages the muscle and blood vessels
that allow a heart to pump blood around the body.
Doctors have long sought a way to repair this damage, and some
experts say that embryonic stem cells hold the answer. Michel
Pucéat of the French National Centre for Scientific Research
in Montpellier and his colleagues performed the research. Pucéat
says that this form of cardiac therapy holds much future promise.
Potential organ donors
Esmail Zanjani, Chairman of Animal Biotechnology at the University
of Nevada, Reno, hopes to use sheep to incubate organs that one
day can be transplanted into humans or cells that can be injected
into human fetuses to treat genetic diseases in vitro.
The project involves taking human stem cells from the bone marrow
of adult volunteers or from one of the federally approved embryo
lines and injecting them into the fetuses of sheep before the
unborn lambs immune system develop enough to reject the
The hybrid animals created by this transgenic mixing of cells
are known as chimeras. Zanjanis work has captured national
and international attention. Each year, thousands of people die
waiting for an organ to transplant.
The first transgenic farm animal was a sheep created in 1985.
Biotechnology firms and research institutes involved in pharmaceutical
development and production use transgenic animals for three different
purposes: as a research model, as a test kit, and as pharmaceutical
This new branch of transgenic animal production which has emerged
in recent years has a new name: pharming. Pharming is the production
of pharmaceutical human proteins in transgenic farm animals.
In most cases of pharming, changing the composition of milk is
the main strategy. Transgenic sheep have been used to produce
Factor IX and VIII to treat hemophilia, human protein C to treat
thrombosis, CFTR to treat cystic fibrosis, and alpha- 1-antitrypsin
(AAT) to help prevent emphysema.
<== SHEEP PRODUCTS