New Zealand’s kākāpō recovery program has been given a major shot in the arm thanks to a significant donation from The Genetic Rescue Foundation supporter Stafford Marquardt and Google.
The woolly mammoth vanished from the Earth 4,000 years ago, but now scientists say they are on the brink of resurrecting the ancient beast in a revised form, through an ambitious feat of genetic engineering.
Speaking ahead of the American Association for the Advancement of Science (AAAS) annual meeting in Boston this week, the scientist leading the “de-extinction” effort said the Harvard team is just two years away from creating a hybrid embryo, in which mammoth traits would be programmed into an Asian elephant.
“Our aim is to produce a hybrid elephant-mammoth embryo,” said Prof George Church. “Actually, it would be more like an elephant with a number of mammoth traits. We’re not there yet, but it could happen in a couple of years.”
Scientists working in coördination with a U.S. conservation group say they’ve established an evolution-warping technology called a “gene drive” in mammals for the first time and could use it to stamp out invasive rodents ravaging seabirds on islands.
Gene-drive technology, so far demonstrated only in insects and yeast, is a powerful way of biasing the inheritance of DNA such that wild animals can be genetically altered as they reproduce, including to cause a population crash.
Now two scientific teams—one in Australia and one in Texas—say they’ve genetically engineered the house mouse, Mus musculus, so that its genome also harbors genetic surprises that could be unleashed on wild populations. The modified rodents were born in the last two months and the results are still preliminary.
The effort to establish gene drives in mammals is being coördinated by Island Conservation, a hard-charging conservation group based in Santa Cruz, California, whose specialty is bombing small islands with rat poison in order to save endangered seabirds. Its motto is “preventing extinctions.”
Until this obstacle is overcome, the technology is unlikely to succeed in the wild.
“These things are not going to get too far in terms of eradicating a population,” says Michael Wade, an evolutionary geneticist at Indiana University Bloomington. Gene drives could result in the genetic isolation — in which populations do not mate with each other — of groups that manage to avoid inheriting the modified genetic code, he and his colleagues found. And gene variants that decrease a population’s propensity to mingle with other populations — such as those that limit flight capacity in insects — would suddenly prove beneficial and could spread.
Resistance to gene drives is unavoidable, so researchers are hoping that they can blunt the effects long enough to spread a desired mutation throughout a population. Some have floated the idea of creating gene drives that target multiple genes, or several sites within the same gene, diminishing the speed with which resistance would develop. By surveying a species’ natural genetic diversity, researchers could target genes common to all individuals.
De-extinction could soon become reality – and the International Union for the Conservation of Nature is already making plans to encourage proper use of the technology.
Gene editing involves altering or disabling existing genes, which used to be extremely difficult. It took many years to develop the gene-editing tool that saved Layla, but thanks to a revolutionary method known as CRISPR, this can now be done in just weeks.
In fact, CRISPR works so well that the first human trial involving the method has already begun. In China, it is being used to disable a gene called PD-1 in immune cells taken from individuals with cancer. The edited cells are then injected back into each person’s body. PD-1 codes for an “off switch” on the surface of immune cells, and many cancers evolve the ability to thwart immune attacks by flipping the PD-1 switch to “off”. On the edited immune cells there is no switch for cancer cells to flip.
UC Berkeley biochemist Jennifer Doudna, molecular biologist Robert Tijan and a team of researchers have expanded the role of the newly discovered CRISPR protein C2c2 that targets RNA instead of DNA.
C2c2 has been described as an RNA-guided RNA-cutting enzyme; however, a full understanding of how this protein acts to cleave RNA was lacking. In a paper published today in Nature titled “Two distinct RNase activities of CRISPR-C2c2 enable guide-RNA processing and RNA detection,” the researchers were able to show that C2c2 has not one, as previously thought, but two distinct RNA cutting activities that in concert can be harnessed for robust RNA detection and degradation.