Editor

Recent Articles

SickKids scientist calls for ‘national strategy’ to get genome sequencing covered in Canada

BY GENNA BUCK
NATIONAL POST
Whole-genome sequencing is not available in Canada yet under any provincial health plan. But Ontario’s health-care quality agency is currently reviewing a proposal to cover it for children with unexplained developmental delay, said Wendy Ungar, director of technology assessment at Toronto’s SickKids hospital, a major Canadian centre for this area of research. Continue Reading →

Filed under:

World’s first living organism with fully redesigned DNA created

BY IAN SAMPLE
THE GUARDIAN

Scientists have created the world’s first living organism that has a fully synthetic and radically altered DNA code.

The lab-made microbe, a strain of bacteria that is normally found in soil and the human gut, is similar to its natural cousins but survives on a smaller set of genetic instructions.

The bug’s existence proves life can exist with a restricted genetic code and paves the way for organisms whose biological machinery is commandeered to make drugs and useful materials, or to add new features such as virus resistance.

In a two-year effort, researchers at the Medical Research Council’s Laboratory of Molecular Biology in Cambridge read and redesigned the DNA of the bacterium Escherichia coli (E coli), before creating cells with a synthetic version of the altered genome.

The artificial genome holds 4m base pairs, the units of the genetic code spelled out by the letters G, A, T and C. Printed in full on A4 sheets, it runs to 970 pages, making the genome the largest by far that scientists have ever built.

“It was completely unclear whether it was possible to make a genome this large and whether it was possible to change it so much,” said Jason Chin, an expert in synthetic biology who led the project.

The DNA coiled up inside a cell holds the instructions it needs to function. When the cell needs more protein to grow, for example, it reads the DNA that encodes the right protein. The DNA letters are read in trios called codons, such as TCG and TCA.

Nearly all life, from jellyfish to humans, uses 64 codons. But many of them do the same job. In total, 61 codons make 20 natural amino acids, which can be strung together like beads on a string to build any protein in nature. Three more codons are in effect stop signs: they tell the cell when the protein is done, like the full stop marking the end of this sentence.

The Cambridge team set out to redesign the E coli genome by removing some of its superfluous codons. Working on a computer, the scientists went through the bug’s DNA. Whenever they came across TCG, a codon that makes an amino acid called serine, they rewrote it as AGC, which does the same job. They replaced two more codons in a similar way.

More than 18,000 edits later, the scientists had removed every occurrence of the three codons from the bug’s genome. The redesigned genetic code was then chemically synthesised and, piece by piece, added to E coli where it replaced the organism’s natural genome. The result, reported in Nature, is a microbe with a completely synthetic and radically altered DNA code. Known as Syn61, the bug is a little longer than normal, and grows more slowly, but survives nonetheless.

“It’s pretty amazing,” said Chin. When the bug was created, shortly before Christmas, the research team had a photo taken in the lab with a plate of the microbes as the central figure in a recreation of the nativity.

Such designer lifeforms could come in handy, Chin believes. Because their DNA is different, invading viruses will struggle to spread inside them, making them in effect virus-resistant. That could bring benefits. E coli is already used by the biopharmaceutical industry to make insulin for diabetes and other medical compounds for cancer, multiple sclerosis, heart attacks and eye disease, but entire production runs can be spoiled when bacterial cultures are contaminated with viruses or other microbes. But that is not all: in future work, the freed-up genetic code could be repurposed to make cells churn out designer enzymes, proteins and drugs.

In 2010, US scientists announced the creation of the world’s first organism with a synthetic genome. The bug, Mycoplasma mycoides, has a smaller genome than E coli – about 1m base pairs – and was not radically redesigned. Commenting on the latest work, Clyde Hutchison, from the US research group, said: “This scale of genome replacement is larger than any complete genome replacement reported so far.”

“They have taken the field of synthetic genomics to a new level, not only successfully building the largest ever synthetic genome to date, but also making the most coding changes to a genome so far,” said Tom Ellis, a synthetic biology researcher at Imperial College London.

But the records may not stand for long. Ellis and others are building a synthetic genome for baker’s yeast, while Harvard scientists are making bacterial genomes with more coding changes. That the redesigned E coli does not grow as well as natural strains is not surprising, Ellis added. “If anything it’s surprising it grows at all after so many changes,” he said.

Continue Reading →

Filed under:

The Great White Shark Genome Is Here

BY MEGAN MOLTENI
WIRED
Is there any more daunting animal to study than the great white shark? Just you try attaching a radio transmitter or drawing a tube of blood from a six-ton, razor-toothed, meat-seeking missile. But scientific understanding of these iconic apex predators has been limited by technical challenges as much as human bias for studying species that reside on closer branches of the taxonomic tree. Sharks evolved from the rest of the animal kingdom 400 million years ago—before the first adventurous amphibians left the oceans for dry land. What could the great white possibly teach 21st century humans? Continue Reading →

Filed under:

Scientists may have found a way to treat cancer without chemotherapy by replicating our body’s own self-destruct system

BY LISA SCHONHAAR
BUSINESS INSIDER
Every day, millions of cells in our bodies “kill” themselves and are quickly removed.
While the mechanism may sound dramatic, it’s for our own good. The process ensures that potentially harmful cells destroy themselves and protects us from diseases.
Cancer cells, however, can protect themselves from self-destruction by ignoring our immune system’s cell-death signals — and that’s precisely what makes them so dangerous.
Continue Reading →

Filed under:

Despite CRISPR baby controversy, Harvard University will begin gene-editing sperm

BY ANTONIO REGALADO
MIT TECHNOLOGY REVIEW
In the wild uproar around an experiment in China that claimed to have created twin girls whose genes were altered to protect them from HIV, there’s something worth knowing—research to improve the next generation of humans is happening in the US, too.

In fact, it’s about to happen at Harvard University. Continue Reading →

Filed under:

The Future of Crime-Fighting Is Family Tree Forensics

BY MEGAN MOLTENI
WIRED
In April, a citizen scientist named Barbara Rae-Venter used a little-known genealogy website called GEDMatch to help investigators find a man they’d been looking for for nearly 40 years: The Golden State Killer. In the months since, law enforcement agencies across the country have flocked to the technique, arresting a flurry of more than 20 people tied to some of the most notorious cold cases of the last five decades. Continue Reading →

Filed under:

Scientists Are Sequencing the Planet’s Genome

BY LUCAS LAURSEN
FORTUNE
A network of scientists around the world Thursday launched a 10-year project to sequence the genomes of all the 1.5 million known plants, animals, and fungi on Earth. The Earth Biogenome Project is a collaboration designed to avoid duplicating one another’s work and to make all genome data inter-operable and open for public use. Its leaders estimate that the total cost will be around $4.7 billion, which is less than the almost $5 billion in inflation-adjusted dollars than the Human Genome Project cost in 2003. Continue Reading →

Filed under: