thenation | On April 18, scientists at Sun Yat-sen University in Guangdong, China, published an article in the obscure open-access journal Protein & Cell
documenting their attempt at using an experimental new method of gene
therapy on human embryos. Although the scientific significance of the
results remains open to question, culturally the article is a landmark,
for it has reanimated the age-old debate over human genetic improvement.
The Chinese scientists attempted to correct a mutation in the
beta-globin gene, which encodes a crucial blood protein. Mutations in
this gene lead to a variety of serious blood diseases. But the
experiments failed. Although theoretically the new method, known as
CRISPR (short for “clustered regularly spaced short palindromic
repeats”) is extremely precise, in practice it often produces
“off-target” mutations. In plain English, it makes a lot of changes in
unintended locations, like what often happens when you hit
“search/replace all” in a word-processing document. The principal
conclusion from the paper is that the technique is still a long way from
being reliable enough for the clinic. Nevertheless, the science media
and pundits pounced on the story, and for a while “#CRISPR” was trending
on Twitter.
CRISPR is the fastest, easiest, and most promising of several new
methods known collectively as “gene editing.” Using them, scientists
can edit the individual letters of the DNA code, almost as easily as a
copy editor would delete, a stray comma or correct a speling error.
Advocates wax enthusiastic about its promise for correcting mutations
for serious genetic diseases like cystic fibrosis and sickle-cell
anemia. Other applications might include editing HIV out of someone’s
genome or lowering genetic risks of heart disease or cancer. Indeed,
every week brings new applications: CRISPR is turning out to be an
extraordinarily versatile technique, applicable to many fields of
biomedical research. I’m pretty immune to biomedical hype, but gene
editing has the marks of a genuine watershed moment in biotechnology.
Once the kinks are worked out, CRISPR seems likely to change the way
biologists do experiments, much as the circular saw changed how
carpenters built houses.
The timing of the paper was provocative. It was submitted on
March 30 and accepted on April 1; formal peer review was cursory at
best. Two weeks before, scientists in the United States and Europe had
called for a moratorium on experiments using CRISPR on human “germ-line”
tissue (eggs, sperm, and embryos), which pass alterations on to one’s
descendants, in contrast to the “somatic” cells that compose the rest of
the body. The embryos in the Chinese experiments were not implanted and
in fact could not have become humans: They were the unviable, discarded
products of in vitro fertilization. Still, the paper was a sensational
flouting of the Westerners’ call for restraint. It was hard not to read
its publication as an East Asian Bronx cheer.
The circumstances of the paper’s publication underline the fact
that the core of the CRISPR debate is not about the technological
challenge but the ethical one: that gene editing could enable a new
eugenics, a eugenics of personal choice, in which humans guide their own
evolution individually and in families. Commentators are lining up as
conservatives and liberals on the issue. Conservatives, such as Jennifer
Doudna (one of CRISPR’s inventors) and the Nobel laureates David
Baltimore and Paul Berg, have called for cautious deliberation. They
were among those who proposed the moratorium on using CRISPR on human
embryos. “You could exert control over human heredity with this
technique,” said Baltimore. George Q. Daley, of Boston Children’s
Hospital, said that CRISPR raises the fundamental issue of whether we
are willing to “take control of our genetic destiny.” Are we ready to
edit our children’s genomes to perfection, as in the movie Gattaca? Could the government someday pass laws banning certain genetic constitutions or requiring others?
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