Menu

Genome-Edited Hornless Cows’ Offspring Are Healthy: Study

All six calves inherited the gene for preventing horn growth, but four also got a piece of the plasmid used to introduce the sequence to their dad—complicating regulatory approval.

Oct 9, 2019
Kerry Grens

ABOVE: Genome-edited bull Buri (top row) was mated with six female horned cows (middle row) and sired six calves (bottom row).
FROM FIGURE 2 OF NAT BIOTECHNOL, DOI:10.1038/S41587-019-0266-0, 2019.

A genetically edited bull successfully passed down to his offspring a gene that scientists had introduced into his genome as an embryo so that he would not grow horns as an adult, scientists reported Monday (October 7) in Nature Biotechnology. The six calves—which, at two years of age, are perfectly healthy, the researchers report—are expected to lack the dangerous horns that are often removed from dairy cows in a process that is labor-intensive, costly, and dangerous itself. 

Four of the calves also inherited a bit of the plasmid that had ferried the hornless gene, called POLLED, into the bull’s genome. The unintended presence of foreign DNA has derailed their route to market in Brazil and the US.

“We’ve demonstrated that healthy hornless calves with only the intended edit can be produced, and we provided data to help inform the process for evaluating genome-edited animals,” coauthor Alison Van Eenennaam, a researcher at the University of California, Davis, says in a press release sent to The Scientist. “Our data indicates the need to screen for plasmid integration when they’re used in the editing process.”

Spotigy and Buri, two bulls that had the POLLLED gene inserted into their genomes from a hornless breed of cattle, were born in 2015. Buri then moved to Davis to be monitored and bred, ultimately siring six calves in September 2017.

See “Designer Livestock

Van Eenennaam’s initial analysis found that the calves were heterozygous for the dominant POLLED allele—just as scientists had hoped they would be. In a number of examinations since they were born, the animals have continued to show good health and no abnormalities, except the lack of horns.

But as she and her colleagues were preparing their manuscript, the US Food and Drug Administration’s (FDA) review of the calves’ genomes spotted the plasmid sequence, inserted right next to the POLLED gene, Wired reports. The agency posted its findings to bioRxiv in July of this year.

The presence of the plasmid felled a partnership between Brazil and Recombinetics, the biotech that developed the hornless cows, and the company is no longer seeking US approval of its modified dairy cattle. To Van Eenennaam’s disappointment, the FDA has decided Buri’s calves cannot be slaughtered for market—even those lacking the plasmid in their genomes—and must be incinerated instead, according to Wired.

Van Eenennaam’s paper was revised to include the discovery of the plasmid sequence in some of the calves—a finding she tells Wired indicates proper oversight of genetically edited animals.

Kerry Grens is a senior editor and the news director of The Scientist. Email her at kgrens@the-scientist.com.

November 2019

Oceanic Connections

Biologists consider the movements of marine animals

Marketplace

Sponsored Product Updates

TTP plc Desktop Biology enables development and manufacture of DnaNudge technology
TTP plc Desktop Biology enables development and manufacture of DnaNudge technology
·        Novel multiplex technology developed to help consumers make healthier choices based on their genetic profile·        TTP involved with all aspects of product development, from initial concept to prototype testing and manufacture·        Culmination of technology and product development partnership spanning just over 3 years
Targos and Ultivue partner to incorporate highly standardized UltiMapper™ tissue multiplex phenotypic assays in support of clinical research services
Targos and Ultivue partner to incorporate highly standardized UltiMapper™ tissue multiplex phenotypic assays in support of clinical research services
Targos Molecular Pathology GmbH, a market leader in clinical biomarker services announced today a technology partnership with Ultivue, the innovation leader in multiplex tissue biomarker assays, to offer the biopharmaceutical industry new capabilities to improve the characterization of cancer patients’ samples selected for clinical research programs. 
MicroMedicine to Launch Automated, Microfluidics-based Cell Isolation Technology at the Society for Immunotherapy of Cancer (SITC) Meeting
MicroMedicine to Launch Automated, Microfluidics-based Cell Isolation Technology at the Society for Immunotherapy of Cancer (SITC) Meeting
MicroMedicine, Inc., a life sciences technology company, today announced that it will be launching its patented one-of-a-kind white blood cell isolation technology, the Sorterra™ Cell Isolation System, at the 34th Annual SITC Conference.
Measuring the Affinity of Challenging Protein Targets
Measuring the Affinity of Challenging Protein Targets
Watch this webinar from Fluidic Analytics to learn more about microfluidic diffusional sizing, how it can be used to measure not only protein size and binding affinity, but also stoichiometry and protein conformation in protein-protein, protein-antibody, and protein-aptamer interactions!