Amazing Science

Cancer DNA tests give only a partial picture of the genes driving the disease, according to a study that throws cold water on the idea that scanning may quickly lead to highly effective personalized treatments. Scientists are well aware that different tumors in the same patient, and different parts of those tumors, may harbor a variety of genetic mutations.

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A living plant has been generated from the fruit of a little arctic flower, making it the oldest plant by far that has ever been grown from ancient tissue.

The field of ancient DNA has gained credibility as new technologies have allowed researchers to do things like reconstitute the Neandertal genome, Wade says. "The Russian researchers tried to germinate the campion seeds but failed. They then took cells from the placenta, the organ in the fruit that produces the seeds. They thawed out the cells and grew them in culture dishes into whole plants," he adds. "If the ancient campions are the ancestors of the living plants, this family relationship should be evident in their DNA. ... If the claim is true, then scientists should be able to study evolution in real time by comparing the ancient and living campions. Possibly other ancient species can be resurrected from the permafrost, including plants that have long been extinct."

Nanopore analysis is an emerging technique that involves using a voltage to drive molecules through a nanoscale pore in a membrane between two electrolytes, and monitoring how the ionic current through the nanopore changes as single molecules pass through it. This approach allows charged polymers (including single-stranded DNA, double-stranded DNA and RNA) to be analysed with subnanometre resolution and without the need for labels or amplification. Recent advances suggest that nanopore-based sensors could be competitive with other third-generation DNA sequencing technologies, and may be able to rapidly and reliably sequence the human genome for under $1,000. In this article we review the use of nanopore technology in DNA sequencing, genetics and medical diagnostics.

In many ways, life is like a computer. An organism's genome is the software that tells the cellular and molecular machinery—the hardware—what to do. But instead of electronic circuitry, life relies on biochemical circuitry—complex networks of reactions and pathways that enable organisms to function. Now, researchers at the California Institute of Technology (Caltech) have built the most complex biochemical circuit ever created from scratch, made with DNA-based devices in a test tube that are analogous to the electronic transistors on a computer chip.

NEW LINK

A team of scientists have discovered a previously unidentified type of small circular DNA molecule occurring outside the chromosomes in mouse and human cells. The circular DNA is 200-400 base pairs in length and consists of non-repeating sequences. The new type of extra-chromosomal circular DNA (eccDNA) has been dubbed microDNA. Unlike other forms of eccDNA, in microDNA the sequences of base pairs are non-repetitive and are usually found associated with particular genes. This suggests they may be produced by micro-deletions of small sections of the chromosomal DNA.

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Scientists at The University of Nottingham have used a revolutionary new DNA-reading technology for a research project that could lead to correct genetic diagnosis for muscle-wasting diseases.

It may look like an ordinary USB memory stick, but a little gadget that can sequence DNA while plugged into your laptop could have far-reaching effects on medicine and genetic research.

The UK firm Oxford Nanopore built the device, called MinION, and claims it can sequence simple genomes – like those of some viruses and bacteria – in a matter of seconds. More complex genomes would take longer, but MinION could also be useful for obtaining quick results in sequencing DNA from cells in a biopsy to look for cancer, for example, or to determine the genetic identity of bone fragments at an archaeological dig.

The company demonstrated today at the Advances in Genome Biology and Technology (AGBT) conference in Marco Island, Florida, that MinION has sequenced a simple virus called Phi X, which contains 5000 genetic base pairs.

Children’s Hospital Boston recently announced a $25,000 competition for the development of an interpretation and communication system that can deliver genomic information from the lab to physicians and patients. As the cost of genome sequencing continues to fall and may break the $1,000 barrier soon, the issue is no longer about acquiring genetic data but about what all the data means. Scientists around the world have been making progress interpreting the molecular language of DNA but, as the Human Genome Project revealed, the human genome contains at least 25,000 genes, so research can be slow going. Furthermore, what information is obtained and published in journals has a hard time finding its way into practices for physicians to understand and apply toward patient care.

For years, scientists believed the vast phenotypic differences between humans and chimpanzees would be easily explained by their genes -- the two species must have significantly different genetic makeups. However, when their genomes were later sequenced, researchers were surprised to learn that the DNA sequences of human and chimpanzee genes are nearly identical. The difference lies in the insertion and deletion of large pieces of DNA near genes which are highly variable between humans and chimpanzees and may account for major differences between the two species.