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 The study from China appeared last weekend in an obscure online
journal called Protein & Cell. In an interview published on
Wednesday on the news site of the journal Nature, lead author Junjiu
Huang of Sun Yat-sen University in Guangzhou said both Nature and
Science rejected the paper, partly for ethical reasons.
"There have been persistent rumors" of this kind of research taking
place in China, said Edward Lanphier, chief executive of
California-based Sangamo BioSciences Inc and part of a group of
scientists who called last month for a global moratorium on such
experiments. "This paper takes it out of the hypothetical and into
the real."
The controversial technique is called CRISPR/Cas9, and represents a
biological version of a word-processing program's "find and replace"
function. Scientists introduce enzymes that first bind to a mutated
gene, such as one associated with disease, and then replace or
repair it.
At least half a dozen experiments have been planned or are underway
using CRISPR on human eggs or embryos to correct genetic defects
such as those causing cystic fibrosis or the BRCA1 breast-cancer
gene, the MIT magazine Technology Review recently reported.
Scientists warn that altering the DNA of human sperm, eggs, or
embryos could produce unknown effects on future generations, since
the changes are passed on to offspring. They distinguish this type
of so-called germline engineering from that which alters the DNA of
non-reproductive cells to repair diseased genes.
"It is too soon to apply these technologies to the human germ line,
the inherited DNA, in a clinical setting," said MIT biologist Rudolf
Jaenisch, president of the International Society for Stem Cell
Research.
Huang's experiments provide evidence of what can go wrong with
CRISPR. His team experimented on 86 one-cell human embryos, they
reported, all from fertility clinics and, because of chromosomal
defects, unable to develop into a baby. Their target was a gene
called HBB, which can cause the blood disease beta-thalassemia.
About a dozen embryos did not even survive the genome-editing, the
scientists reported.
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Of the surviving embryos, many showed "off-target" effects, they
reported, meaning genes other than HBB were altered. Other embryos
suffered "untoward mutations." Only a handful of embryos contained
the healthy DNA meant to repair the defective HBB genes.
"If you want to do it in normal embryos, you need to be close to 100
percent" on target in terms of fixing only the target gene, Huang
told Nature News, which reported that four or more groups in China
are doing similar experiments. "That's why we stopped."
Science and Nature said their policy is not to comment on
publication decisions. Springer, which publishes Protein & Cell and
is owned by European private equity firm BC Partners, did not
immediately reply to questions about its decision to publish Huang's
paper.
According to a note in Protein & Cell, the paper was received on
March 30 and accepted on April 1. Two days is an unusually-short
amount of time for a complicated study to undergo peer review by
journal editors and outside scientists for rigor and accuracy.
Lanphier fears that the call for a moratorium on editing the human
germline is being ignored. "This is the first of what may be many
papers" on human germline engineering, he said.
(Reporting by Sharon Begley; Editing by Michele Gershberg and Andrew
Hay)
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