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Artificial insemination is used to improve the genetics of dairy cattle, like this bull.Credit: Leonhard Foeger/Reuters

Bulls are being injected with sperm-producing stem cells from other males that have more-desirable genetics. The recipient bull’s own sperm production is first impaired through gene editing — so, from then on, his offspring will be the donor’s. If scientists can surmount lingering technical hurdles, the technique could be used for other livestock that are tricky to breed using artificial insemination, and for conserving species for which semen storage is difficult.

Nature | 5 min read

Biologists raised lice for four years on differently coloured rock pigeons to watch how they would adapt. Not only did the lice change colour to blend in with their hosts — they reached the colour extremes found on other lice species that have been merrily adapting on other types of bird for millions of years. It goes to show that for parasites, the host is their environment — and the pressure of surviving on that “host island” is a powerful driver of evolutionary change.

The Atlantic | 6 min read

Reference: Evolution Letters paper

HUMAN GERMLINE GENE-EDITING

A human embryo at the eight-cell stage.Credit: Yorgos Nikas/SPL

Eighteen leading ethicists and researchers from seven countries, including some of those who originally developed CRISPR–Cas9 as a gene-editing tool, are calling for the world to adopt a moratorium on editing human genes that can be passed to the next generation.

• “By ‘global moratorium’, we do not mean a permanent ban,” say the writers — “rather, we call for the establishment of an international framework in which nations, while retaining the right to make their own decisions, voluntarily commit to not approve any use of clinical germline editing unless certain conditions are met.” Also, the proposed moratorium would not apply to germline editing for research purposes, in which no gene-edited baby is born. (17 min read)

• The bold call follows the controversial claim made by biophysicist He Jiankui that he had become the first to make such a change in the DNA of two embryos. Also, “scientists who were apparently aware of this work did not take adequate measures to stop it”, note the ethicists and researchers. (13 min read, from February)

• Nature responds to the call with an editorial exploring how such a moratorium could be implemented — and whether it would work at all. “China had regulations on gene editing that amounted to a national moratorium, but they clearly didn’t work,” it notes. Nevertheless, germline gene-editing research needs rules, it argues. The journal also asks for stakeholders to chime in, especially those whose voices have been somewhat sidelined so far, such as patient groups and those experienced with related research and regulations. (5 min read)

• The US National Institutes of Health supports the moratorium, calling for deep reflection at this “crucial moment in the history of science” in which “a new technology offers the potential to rewrite the script of human life”. The Royal Society, the US National Academy of Sciences and the US National Academy of Medicine offer a plan of action through their international commission, which is supported by dozens of scientific academies around the world. (Both 3 min reads)

The Comment article in Nature that kicks it all off | 17 min read

All about the CRISPR-baby controversy (from February) | 13 min read

Nature’s editorial | 5 min read

The NIH response | 3 min read

The national academies’ action plan | 3 min read

FEATURES & OPINION

Colombian ecologist Cristian Román-Palacios managed to score a place at the University of Arizona in Tucson, but found the process of applying to graduate school in the United States confusing. “This is what I wish somebody had told me when I started,” he says, offering five detailed steps to success.

Nature | 4 min read

An almost-all-electric transport network, a sharing economy and a lot less meat are just some of the changes in NPR’s extremely optimistic future scenario for a world remade to stop climate change. The analysts who contributed agree that the biggest barrier to such a future isn’t developing the solutions, but finding the collective will to use them.

NPR | 13 min read