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发帖数: 1 | 1 转自Bloomberg：
https://www.bloomberg.com/amp/opinion/articles/2018-11-27/crispr-fears-
designer-baby-outrage-won-t-last-as-ethics-evolve
It’s too soon to know whether a Chinese researcher who claims to have
successfully edited the genomes of newly born twins is telling the truth.
But if he is, and if the girls turn out to be healthy and normal, it heralds
a significant change in the scientific and ethical status of human gene
editing. The outrage might not last long.
The consensus in the scientific community now is that human gene editing is
medically dangerous and ethically wrong. Both of those beliefs are
susceptible to changing, almost as fast as science is capable of progressing.
And, interestingly, the two main concerns about gene editing using the
Crispr-Cas 9 system are almost diametrically opposed, logically speaking.
The first worry is that Crispr technology, while cheap and powerful, isn’t
reliable enough for use in humans. Specifically, the concern is that changes
in one gene that has been “knocked out” and replaced with another could
have unforeseen and harmful effects elsewhere in the genome.
Called “off-target” effects, such unintended modifications are rare but
not unheard of in Crispr experiments in mice. When it comes to humans, the
worry goes, an intended mutation that is beneficial or even lifesaving could
turn out to have serious, permanent negative effects elsewhere.
The second worry is that Crispr editing of the human genome will work all
too well. That could lead to parents seeking to have designer babies,
offspring whose genomes have been edited so that they will be more athletic
or more attractive or more intelligent.
The ethical concerns there range from the obvious (it seems too much like
eugenics) to the more subtle (it could enhance class differences between
those with access to the technology and those without).
Then there’s the fact that gene editing isn’t restricted to that one child
. Crispr genetic mutations are passed on to the next generation, whether for
good or for ill.
These scientific and ethical concerns are serious. But they can change fast.
Consider the off-target effects. This worry is based on empirical science:
either there is a meaningful probability of dangerous off-target mutations,
or there isn’t. If children like the twins who have been reportedly
modified are born and live healthy, normal lives, then scientific worries
about off-target effects will begin to recede.
As an editorial in Nature Medicine pointed out last summer, all acts of
sexual reproduction carry a background probability of spontaneous mutation
— that’s why evolution is possible. If the rate of off-target effects is
lower than that of natural mutation, scientists and regulators may come to
consider it to be tolerable.
That leaves the designer-babies worry — and there are a couple of reasons
to predict that it, too, may fade.
To begin with, designing taller or smarter babies is not a realistic
possibility in the foreseeable future. Most observable human features are
associated with hundreds of genetic mutations, not just one or two. One
leading study on height found that 697 genetic variants accounted for one-
fifth of the difference among people. It isn’t realistic to use Crispr to
knock out and replace those 697 genes to achieve a possible 20 percent gain
in height.
Other examples of human variability, such as intelligence, would be even
harder to change with current editing techniques. We can’t even produce a
consistent definition of intelligence, much less identify its genetic
determinants.
As the public gradually realizes that designer babies aren’t a very
realistic option, the ethical worry about producing them is likely to fade.
What will remain is the strong ethical value of protecting future
generations from debilitating disease. The reported Chinese human editing
case was unnecessary, because there are other, simpler ways of protecting a
fetus from contracting HIV from a paternal donor. But plenty of other
diseases can be avoided only by genetic mutation.
If and when it becomes scientifically safe to proceed with human gene
editing, the legitimate ethical concern about designer babies is likely to
be outweighed by the ethical imperative to avoid disease, and to enable
parents to reproduce who might otherwise not have been able to do so.
Over time, the ethical question will cease to be whether it is permissible
to use gene editing to prevent disease. Instead, ethicists will be asking
whether it is ethically permissible not to make interventions that would
avoid human pain and suffering.
All this will take time — possibly as long as a decade, depending on how
many scientists break the current norms and how well their patients do. But
if the science works, expect the ethical norms to follow. Forty years ago,
ethicists fretted about in vitro fertilization. Today, the practice seems
ethically unproblematic or even attractive to the public in most countries. | s******r
发帖数: 5309 | 2 基因编辑这个技术商业潜力巨大，花街表示坚决支持。 | l*******2
发帖数: 1 | 3 看看韩春雨 贺建奎就知道了，从来没有哪个领域有这种轰动效应
【在 s******r 的大作中提到】
: 基因编辑这个技术商业潜力巨大，花街表示坚决支持。
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