Category Archives: Transhuman News

"Sign Dna" / Marcin Banasiak / (facebook.com/NuRec.HD)

By: Marcin Banasiak

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"Sign Dna" / Marcin Banasiak / (facebook.com/NuRec.HD) - Video

DNA robots crawl across a surface made of DNA.

DNA-based nanotechnology has been around for more than 30 years, but it really took off in 2006, when DNA origami was featured on the cover of Nature. This form of origami, the folding of DNA into 2D and 3D shapes,was more of an art form back then, but scientists are now using the approach to construct nanoscale robots.

The basic principle of DNA origami is that a long, single-stranded DNA molecule will fold into a predefined shape through the base-pairing of short segments called staples. All thats required is to ensure that each staple can find a complementary match to base-pair with at the right location elsewhere in the molecule. This approach can be used to create both 2D and 3D structures.

The idea behind the new work is that a DNA origami robot can be programmed to have a specific function based on a key, which can be a protein, a drug, or even another robot. Once the right key and the right robot find each other, the key drives a conformational (structural) change in the robot. The new shape causes the robot to perform a programmed function, such as releasing a drug.

More recently, scientists from Harvard and Bar-Ilan Universities have figured out how to use DNA origami to make robots that behave like fundamental logic units. The scientists used these DNA-based discrete elements to construct a collision-based computer, with the collisions being between a key and a robot. Various logic gatesAND, OR, XOR, NAND, NOT, CNOT, and a half addercould be put together using different combinations of robots.

The DNA gates all take two inputs in the form of other molecules. AND gates require that both inputs be present to open, while OR gates only require that one be present. In the diagram below, the far left block diagram represents an AND gate, and the one next to it depicts an OR gate. Using the same principles, the DNA origami strands can be synthesized to form different logic elements, as shown by the XOR and half adder.

Amir et. al.

Using this technology, the scientists constructed a logically complete NAND gate and a NOT (or inverter) gate.

A solution containing these specially constructed DNA origami elements was then injected into cockroaches to demonstrate that these synthesized logic elements can work in a biological context. In the case of the cockroaches, the scientists extracted haemocytes (the invertebrates version of a white blood cell) and validated the effectiveness of the robots ability to respond to their programmed keys within the cells.

The scientists propose that their DNA origami system could serve as a controller for drug release throughout different disease states. Their design involves three effector robots that all carry a specific drug. These robots respond to four regulator proteins (cues) that act as inputs and trigger a layer of logic gates (AND and OR). The output is a specific combination of drugs tailored to the combination of proteins present.

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DNA-based logic gates operate inside cockroach cells

HOUSTON (AP) An analysis of Houston police sexual assault kits, which at one time went years without being tested, has resulted in DNA evidence that implicated a prison inmate in multiple assaults dating to 1992, police officials said.

Texas prison system records show 43-year-old Herman Ray Whitfield on Wednesday was in the Byrd Unit in Huntsville, serving time for kidnapping.

Police announced Tuesday that Whitfield has been charged with aggravated sexual assault of a child and three counts of aggravated sexual assault. The outcome came as part of DNA evidence testing on an extensive backlog of police sexual assault kits.

The attacks happened from 1992 to 1994, and again from 2006 to 2009, in bushes, on trails and at vacant properties, authorities said, adding that they believe others were attacked.

Whitfield was convicted of kidnapping in 1995, paroled in 2006 and returned to prison in 2009 for a parole violation. Online prison records don't list an attorney for him.

"He was very violent in his assaults," Sgt. John Colburn said of the 6-foot-3 Whitfield. "He choked his victims and would display a weapon or let them know he had one."

The announcement comes a year after two independent labs began processing about 10,000 cases including 6,600 untested kits that were stored in the Houston police department's property room, according to the Houston Chronicle (http://bit.ly/ODH9Zy ). The oldest of the untested kits dates to 1987.

City leaders last year approved spending $4.4 million to send evidence for testing at two independent labs.

The testing was necessary not only to eliminate the backlog, but also to keep up with a growing number of newer cases developed by investigators that required DNA testing.

Houston police closed their crime lab in 2002. An independent audit criticized the lab, citing unqualified personnel, lax protocols and inadequate facilities that included a leaky roof that allowed rainwater to contaminate evidence, according to the Chronicle.

The rest is here:
DNA matches Texas inmate in Houston cold cases

FACE OF THE FUTURE: Dr Dennis McNevin is part of a team developing DNA tests that can draw exact pictures of suspects. Photo: Jeffrey Chan

Australian police and researchers are developing a ground-breaking test that will help them identify suspects based on the DNA evidence they leave behind.

It is set to change the way police use DNA evidence. Officers may soon be able to use a single strand of hair from a crime scene to pinpoint whether a suspect has a cleft chin, how many moles they have and whether or not they are bald.

The University of Canberra's Dennis McNevin is working on the four-year project set to finish at the end of next year and called ''From Genotype to Phenotype: Molecular Photofitting'', with Victoria Police, the Australian Federal Police and the Queensland Institute of Medical Research. He said Australian police now used DNA evidence to link an existing suspect to a crime scene, but eventually research might lead to their using DNA to create photofit images of potential suspects.

Victoria Police forensic officer Runa Daniel, who is working on the project with her colleague Roland van Oorschot, said the research could be used in the absence of other leads or to supplement eyewitness statements.

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''DNA phenotyping may provide more accurate information on some characteristics and could be used to direct valuable police and forensic resources in the primary and critical stages of an investigation, particularly when traditional DNA profiling techniques have not been informative,'' she said.

Dr McNevin said there were DNA tests to determine hair and eye colour, but this new research was working towards pinpointing other distinctive features, including ear lobes attached to a person's face and their bio-geographic ancestry, and the team was already fairly confident in identifying male pattern baldness.

''There are situations commonly encountered where there are no suspects, or there is a very large pool of suspects, and it becomes unfeasible to collect a reference DNA sample from what could be hundreds of different suspects this is where we might want to collect intelligence value from that DNA,'' he said.

DNA testing could identify if a person was from a broadly European, Asian or African background and Dr McNevin said he hoped to add Oceanic, indigenous American and perhaps others to that list by the end of next year.

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DNA to pick out suspect, warts and all