POLLY - THE FIRST GENETICALLY ENGINEERED CLONED SHEEP
A Church of Scotland View
In February 1997, the Roslin Institute and PPL Therapeutics plc
announced the first production of Dolly, the cloned sheep who
was the first mammal to be cloned from the somatic tissue of an
adult. Dolly was of almost the same genetic composition as the
sheep from whose cells she was developed, but she was not
genetically engineered as such. Five months later, on 24 July,
PPL announced that Polly, a genetically engineered lamb, had
been produced by the same method of nuclear transfer that had
produced Dolly. In addition to her usual complement of sheep
genes, she also contained a human gene which had been added to
the cells while they were still a cell culture. The full
details of the work have yet to be published, but this
represents an important development.
The gene is one intended to produce a therapeutically useful
protein in the milk of the sheep. Genetically modified sheep of
this general kind have been produced by Roslin and PPL for a
number of years, using a "conventional" method of genetic
manipulation known as micro-injection. Now this manipulation
has been achieved by the Roslin's nuclear transfer method. This
was the next logical step for Roslin and PPL from producing
Dolly, and although not as dramatic a piece of science as Dolly,
it represents possibly a more important breakthrough in what it
could mean for animal genetic engineering. Its technical
significance is that in principle it gives geneticists a far
more precise way of doing genetic manipulation, and a far wider
range of genetic changes which they could do in farm animals,
compared with the limited and rather "hit and miss" methods
which have been used hitherto.
Return to Contents
From an ethical point of view, this does not pose any particular
new problems. In May the General Assembly of the Church of
Scotland expressed an overall approval for the Roslin and PPL
work towards producing therapeutic proteins in the sheep's milk.
It expressed serious concerns about cloning of animals, if the
nuclear transfer methods which produced Dolly were to be done
routinely in agricultural production. But it saw no objection
to their use for the very limited purpose of producing
transgenic sheep for producing therapeutic proteins, which PPL
have just announced. Polly indeed represents the logical next
step in this work.
This is not to say that all genetic modification of sheep or
other animals is necessarily justified, but this area of
application is ethically acceptable in that it offers
significant human medical benefits, with a relatively small
intervention in the animals. It is also important to recognise
that these are preliminary results. It remains to be seen how
effective the method would prove in other circumstances, or on
other animals.
Return to Contents
There are many unknowns about the nuclear transfer technology
and the way it works. As pointed out at the time of earlier
Dolly announcement, much development work is necessary, and in
particular, assurances will be needed that the animal welfare
aspects would be acceptable. Important questions have been
raised about the number of failed pregnancies and unusually
large progeny which appear to be resulting from the nuclear
transfer experiments which Roslin have performed to date. While
the suffering does not appear to be so extreme that one would
wish to put a stop to this work already, it is clearly necessary
to understand the causes and establish whether the problems can
be prevented, before the method could be allowed for more
general use. It would seem fair to allow the Roslin scientists
a chance to do this. If after a reasonable time there seemed
little prospect doing so, then one would have to review whether
it was ethical to go ahead any further. Roslin themselves have
indicated they would not wish to proceed with a technique which
was shown to have insoluble welfare problems.
Return to Contents
As with Dolly, in theory the method might be applicable to
humans, in order to achieve the germline genetic engineering of
human beings. Roslin and PPL have no such intentions. Indeed,
it would be illegal in the UK and a number of other countries.
There would be immense technical difficulties in pursuing such
an idea. But it would also raise enormous ethical problems, not
only regarding germline therapy, but also because the result
would mean that they were clones. The Church of Scotland, along
with many other bodies, has already expressed its opposition to
the application of nuclear transfer technology to whole human
beings, because cloned individuals would result, representing an
abuse of human individuality. But, people argue, if the
scientific knowledge is there, someone else might try to do such
work. It is therefore up to citizens of each country to press
for legislation and controls to make that impossible worldwide.
Return to Contents
Back to Cloning home page
This page has been produced by the Society Religion and Technology Project of the Church of Scotland (SRT for short), and is copyright, Donald M.Bruce, 1996. We're usually happy for people to reproduce all or part of our articles, but please write or email us for permission first, at our address below.
Return to the top of the Page
This page has been produced by the Society Religion and Technology Project of the Church of Scotland. For more about our work on other issues, see our Other SRT Project pages, our SRT Publications List, or our On-line SRT Newsletter.
We'd also welcome any comments you may have. We don't claim to have said the last word!
If you want to send us a comment or obtain further information or receive our latest Newsletter,
email us at :
mailto:srtp@srtp.org.uk
or send an ordinary letter or fax to :
Dr.Donald M.Bruce,
Society, Religion and Technology Project,
, 121 George Street, Edinburgh, EH2 4YN, Scotland.
tel. +44 (0)131-240 2250, fax +44 (0)131-240 2239,
email address : srtp@srtp.org.uk
Return to Contents
Return to Further Information
This page has been produced by the Society Religion and Technology Project of the Church of Scotland. For more about our work on other issues, see our Other SRT Project pages, or our SRT Publications List.
We'd also welcome any comments you may have. We don't claim to have said the last word!
If you want to send us a comment or obtain further information or receive our latest Newsletter,
email us at :
mailto:srtp@srtp.org.uk
or send an ordinary letter or fax to :
Dr.Donald M.Bruce,
Society, Religion and Technology Project,
, 121 George Street, Edinburgh, EH2 4YN, Scotland.
tel. +44 (0)131-240 2250, fax +44 (0)131-240 2239,
email address : srtp@srtp.org.uk
Return to Contents
Return to Further Information
|
SRT PROJECT WEBSITE - SUBJECT INDEX
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Return to Contents
Return to Further Information
Links to other SRT Project Pages
SRT Website Map
