 |
|
|
''The Cloning of Adults Is Impossible'' |
|
By Mario Osava *
RIO DE JANEIRO – Mayana Zatz is one of the
many women who have contributed to making Brazil the most advanced
Latin American nation in terms of genetic research. Zatz is the
coordinator at the Center for Human Genome Studies at the University
of Sao Paulo and conducts research in progressive muscular dystrophies.
She also heads a medical assistance association for ill children,
and has published 160 studies in various journals. As a result of
all this, she was one of the five recipients of this year’s UNESCO/L’Oreal
Prize for Women Scientists.
Q: What are muscular dystrophies?
A: They are genetically transmitted diseases that cause the progressive
and irreversible degeneration of the body’s musculature, and as
a result cause a great deal of suffering for the ill individual
and his or her family. They affect one out of every 2,000 births.
There are more than 30 types, though the most serious and common
is Duchenne muscular dystrophy, which is manifest only in boys,
who by age 10 already need a wheelchair for mobility.
Q: Why does research involving these diseases provide so much
genetic knowledge?
A: Because of their high incidence and characteristics. By studying
the genes that cause the disease we come to understand how they
act in their normal state and why they cause diseases if they are
modified. Duchenne muscular dystrophy, for example, is hereditary
in two-thirds of the cases, there is a risk of repetition with families.
The sisters of affected boys do not present the disease themselves,
but can pass it on to their sons. Prevention is very important.
There are already tests that provide a reliable prenatal diagnosis,
but Latin America lacks legislation that would allow the termination
of a pregnancy if the fetus is found to have a grave genetic disease.
Q: Is genetics an area in which developing countries are in better
conditions to make scientific advances, as has occurred in Brazil?
A: In Brazil we have our great biodiversity as an advantage. In
human genetics, the mixing of races favors the study of different
genetic groups. In addition, we have larger families, which are
the source of a great deal of information. These factors are less
frequent in industrialized countries.
Q: Why are you against cloning but a supporter of genetic therapy?
A: The cloning of adult humans is only a fantasy, scientists will
never be able to create an exact copy. If even identical twins,
coming from the same embryo and raised together are different, imagine
two people separated by many years but with the same genes. Additionally,
the use of adult cells, already adapted to specific functions, will
always cause problems for cloning. It is different from genetic
treatments using mother cells, or T-cells, which maintain their
capacity to transform themselves into other tissues, such as muscles,
a liver or other organs for transplant. These cells are plentiful
in umbilical cords and in embryos, which are discarded by fertilization
clinics.
Q: Doesn’t that create ethical problems?
A: There are people who are opposed to it because embryos might
be used in reproductive cloning or bought and sold. But these are
debates for the future. The ethical problem today, one society should
be discussing, is the use of genetic testing, which is continually
being improved. One test identifies, in people who will never be
affected, the risk of having children with muscular dystrophy or
other diseases, and allows the choice of avoiding it. Another involves
diseases that would be manifest later in life. A test can indicate,
for example, that a normal person will have genetic mutations or
has a higher risk of this. I am against those tests that predict
diseases that are still untreatable because they could serve the
interests of insurance companies, health insurance providers and
employers.
Q: Do you support the cultivation of genetically modified seeds?
A: I am in favor of it because it is not very different from the
hybrids that have provided the wonderful diversity of fruits and
vegetables we enjoy today. They present no risk to human health,
but their environmental impact should be studied more closely.
* Mario Osava
is an IPS correspondent.
|
