Scientists have recovered DNA from mammoth fossils found in Siberian permafrost that are more than a million years old. This DNA—the oldest genomic evidence recovered to date—illuminates the evolutionary history of woolly mammoths and Columbian mammoths. It also raises the prospect of recovering DNA from other organisms this ancient—including extinct members of the human family.
Ever since the recovery of two short DNA sequences from a recently extinct zebra subspecies known as the quagga in 1984, researchers have been working to get ever larger amounts of DNA from ever older remains. Advances in ancient DNA extraction and sequencing methods eventually brought to light genomes of creatures from deeper time, including cave bears and Neandertals.
In 2013, investigators announced that they had retrieved DNA from a 700,000-year-old horse fossil—by far the oldest genomic data ever obtained. But as astonishingly old as that genetic material was, some experts predicted that sequenceable DNA should survive more than a million years in fossils preserved in frozen environments.
The new findings, published today in Nature, bear that prediction out. Tom van der Valk and Love Dalén of the Center for Paleogenetics in Stockholm and their colleagues obtained DNA from molar teeth belonging to three mammoths from different time periods. Mammoth species can be distinguished on the basis of dental characteristics. One tooth, discovered in deposits thought to be around 700,000 years old, looked like that of an early woolly mammoth, Mammuthus primigenius. The other two teeth—one dated to around one million years ago and the other to 1.2 million years ago or more—resembled molars of the steppe mammoth, Mammuthus trogontherii.
Read the full article at: www.scientificamerican.com
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CRISPR has sparked a renaissance in genome editing. Now, next-generation CRISPR technologies let scientists modify the genome more efficiently and precisely than before. Such tools could one day serve as therapeutics, but many challenges remain.
Most drugs are small molecules that can be packaged into a pill. Genome editors are large, complicated molecules – so scientists can’t just stuff them into a pill for people to swallow, or inject them into people’s bodies. They have to find other ways to get the molecules into patients’ cells. One method relies on viruses, says Guangping Gao, a gene therapy researcher at the University of Massachusetts Medical School and president of the American Society of Gene and Cell Therapy. Scientists could potentially package genome editors into small viruses like adeno-associated viruses, for example. These viruses, which have already seen clinical use in several FDA-approved drugs, could then infect patients’ cells and dump their payloads.
It could be that scientists will need to develop entirely different delivery systems. Researchers are currently experimenting with lipid nanoparticles and using electric fields to coax genome editors into cells that can then be transplanted into patients. Delivery remains a major hurdle, Gao says, but he’s still excited about genome editors’ potential. “Gene therapy is now in its golden age,” he says. And genome editors “open even more avenues for treating disease.”
Read the full article at: www.hhmi.org
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Latest NASA Perseverance News is HERE
Ingenuity has phoned home from where it is attached to the belly of NASA’s Perseverance rover. Mission controllers at NASA’s Jet Propulsion Laboratory in Southern California have received the first status report from the Ingenuity Mars Helicopter, which landed Feb. 18, 2021, at Jezero Crater attached to the belly of the agency’s Mars 2020 Perseverance rover. The downlink, which arrived at 3:30 p.m. PST (6:30 p.m. EST) via a connection through the Mars Reconnaissance Orbiter, indicates that both the helicopter, which will remain attached to the rover for 30 to 60 days, and its base station (an electrical box on the rover that stores and routes communications between the rotorcraft and Earth) are operating as expected.
“There are two big-ticket items we are looking for in the data: the state of charge of Ingenuity’s batteries as well as confirmation the base station is operating as designed, commanding heaters to turn off and on to keep the helicopter’s electronics within an expected range,” said Tim Canham, Ingenuity Mars Helicopter operations lead at JPL. “Both appear to be working great. With this positive report, we will move forward with tomorrow’s charge of the helicopter’s batteries.”
Read the full article at: mars.nasa.gov
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