60 posts tagged DNA
Synthetic biologists have cooked up something new: an entirely synthetic chromosome. The development is being hailed as a milestone for biology. It could lead to microbes that produce exotic materials not found in nature. The synthetic chromosome is the end product of a seven-year endeavour led by Jef Boeke of Johns Hopkins University in Baltimore, Maryland. It is a version of yeast chromosome III, one of the smallest out of the 16 that yeast contains. Boeke’s team previously made artificial versions of sections from two other yeast chromosomes. Crucially, the artificial chromosome contains a suite of changes, compared with the naturally occurring variety. “We spent about a year debating what changes we should build into the chromosome so we could really learn something from the experience,” says Boeke. For instance, the natural chromosome III contains about 315,000 letters of the genetic code. The synthetic version – SynIII – contains just 270,000, making it a little easier to build. To cut it down, the researchers looked at the sequence on a computer and identified non-coding, “junk” DNA, which they could delete without killing the yeast.
Scientists hail synthetic chromosome advance
Scientists have created the first synthetic chromosome for yeast in a landmark for biological engineering. Previously synthetic DNA has been designed and made for simpler organisms such as bacteria. As a form of life whose cells contain a nucleus, yeast is related to plants and animals and shares 2,000 genes with us. So the creation of the first of yeast’s 16 chromosomes has been hailed as “a massive deal” in the emerging science of synthetic biology. The genes in the original chromosome were replaced with synthetic versions and the finished manmade chromosome was then successfully integrated into a yeast cell. The new cell was then observed to reproduce, passing a key test of viability. Yeast is a favoured target for this research because of its well-established use in key industries such as brewing and baking and its potential for future industrial applications. One company in California has already used synthetic biology to create a strain of yeast that can produce artemisinin, an ingredient for an anti-malarial drug. The synthesis of chromosome III in yeast was undertaken by an international team and the findings are published in the journal Science (yeast chromosomes are normally designated by Roman numerals). (via BBC News - Scientists hail synthetic chromosome advance)
Eventually, the researchers think that they might approximate the image of a parent from the DNA of children or better visualize some of Homo sapiens’ ancestors by looking at DNA. On a more practical level, law enforcement groups might be able to create a “mug shot” from DNA to identify both victims and criminals.
3D models connect DNA to facial features
Penn State, Stanford University, University of Pennsylvania -> Original Study
-Using 3D models, researchers are closer to connecting genetics with facial features. Eventually, they hope the findings will lead to predicting facial features from DNA evidence.
“By jointly modeling sex, genomic ancestry, and genotype, the independent effects of particular alleles on facial features can be uncovered,” the researchers state in PLOS Genetics.
They add “by simultaneously modeling facial shape variation as a function of sex and genomic ancestry along with genetic markers in craniofacial candidate genes, the effects of sex and ancestry can be removed from the model thereby providing the ability to extract the effects of individual genes.”
In essence, by including sex and racial admixture, researchers can learn about how certain genes and their variations influence the shape of the face and its features.
“We use DNA to match to an individual or identify an individual, but you can get so much more from DNA,” says Mark D. Shriver, professor of anthropology at Penn State. “Currently we can’t go from DNA to a face or from a face to DNA, but it should be possible.”
Probably the best BBC Knowledge Explainer about DNA ..
BBC Knowledge and Learning is exploring a wide variety of topics from social history to science in a series of three-minute online Explainer documentaries, and commissioned Territory (territorystudio.com) to produce an animated film on the subject of DNA.
As Will Samuel, lead designer and animator on the project explains, the approach taken wasn’t just to look into a scientific future. “We needed to find a graphic style to communicate the beauty and intricacy of DNA. We wanted to create nostalgia; taking the audience back to the days of textbook diagrams and old science documentaries, such as Carl Sagan’s COSMOS and IBM’s POWER OF TEN (1977). Using the double helix circular theme as a core design we focused on form, movement and colour to create a consistent flow to the animation, drawing on references from nature, illustrating how DNA is the core to everything around us.”
Three minutes is a short time to explore a subject where most doctorates only scratch the surface, so writer Andrew S. Walsh teamed up with molecular biologist Dr Matthew Adams to distil the script down to the most fundamental elements required to understand not only DNA’s form and function but how our understanding of these discoveries has affected the wider world. While this length may feel restrictive, the team found that this limitation acted as a lens, focusing the piece on the essentials.
The Explainer series is designed to intrigue and inform, encouraging those who discover the documentaries to further explore through links to additional information found on the BBC website.
For Nicholas Hud, a chemist at the Georgia Institute of Technology, the turning point came in July of 2012 when two of his students rushed into his office with a tiny tube of gel. The contents, which looked like a blob of lemon Jell-O, represented the fruits of a 20-year effort to construct something that looked like life from the cacophony of chemicals that were available on the early Earth. To some biochemists, Hud’s attempts to find an evolutionary precursor to ribonucleic acid may have seemed a fool’s errand. The dominant theory to explain the origins of life — known as the RNA world hypothesis — regards ribonucleic acid as the first biological molecule. Its allure comes from the molecule’s dual nature. Unlike DNA, the molecule that provides the blueprint for all living things, RNA acts as both an information carrier and an enzyme, catalyzing reactions. That means the molecule has the potential to copy itself and to pass along its genetic code, two essential components for Darwinian evolution. If RNA was indeed the first biological molecule, discovering how it first formed would illuminate the birth of life. The basic building blocks of RNA were available on prebiotic Earth, but chemists, including Hud, have spent years trying to assemble them into an RNA molecule with little success. About 15 years ago, Hud grew frustrated with that search and decided to explore an alternative idea: Perhaps the first biological molecule was not RNA, but a precursor that possessed similar characteristics and could more easily assemble itself from prebiotic ingredients. Perhaps RNA evolved from this more ancient molecule, just as DNA evolved from RNA.
Baffling 400,000-Year-Old Clue to Human Origins
Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries. In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years. The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found. The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery. “Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study. (via Baffling 400,000-Year-Old Clue to Human Origins - NYTimes.com)
Phobias may be memories passed down in genes from ancestors
Memories may be passed down through generations in DNA in a process that may be the underlying cause of phobias
Memories can be passed down to later generations through genetic switches that allow offspring to inherit the experience of their ancestors, according to new research that may explain how phobias can develop. Scientists have long assumed that memories and learned experiences built up during a lifetime must be passed on by teaching later generations or through personal experience. However, new research has shown that it is possible for some information to be inherited biologically through chemical changes that occur in DNA. Researchers at the Emory University School of Medicine, in Atlanta, found that mice can pass on learned information about traumatic or stressful experiences – in this case a fear of the smell of cherry blossom – to subsequent generations. The results may help to explain why people suffer from seemingly irrational phobias – it may be based on the inherited experiences of their ancestors. (via Phobias may be memories passed down in genes from ancestors - Telegraph)
DNA hint of European origin for dogs
The results of a DNA study suggest that dogs were domesticated in Europe. No-one doubts that “man’s best friend” is an evolutionary off-shoot of the grey wolf, but scientists have long argued over the precise timing and location for their emergence. The new research, based on a genetic analysis of ancient and modern dog and wolf samples, points to a European origin at least 18,000 years ago. Olaf Thalmann and colleagues report the investigation in Science magazine. It adds a further layer of complexity to the story. (via BBC News - DNA hint of European origin for dogs)