Arts, Research, Science, Technology, United States

DNA Phenotyping…

FORENSIC COMPUTER SCIENCE

Intro: DNA Phenotyping is the prediction of physical appearance from DNA

Until now, DNA left at the scene of a crime only proved useful if it was already stored in a database and could be matched to a suspect.

A team of forensic experts, however, have now devised a way to recreate the face of a person, including eye and skin colour, using as little as 50 picograms (0.05 nanograms) of extracted DNA.

Called DNA phenotyping, the tests also determine the person’s ancestry, if they have freckles and can be used to match with distant relatives.

DNA phenotyping is the prediction of physical appearance from DNA and is a technique being pioneered by Virginia-based Parabon Nanolabs (example pictured). The technology can be used to generate leads in cases where there are no suspects or database hits, or to help identify remains, for example.

DNA phenotyping is the prediction of physical appearance from DNA and is a technique being pioneered by Virginia-based Parabon Nanolabs (example pictured). The technology can be used to generate leads in cases where there are no suspects or database hits, or to help identify remains, for example.

DNA phenotyping is the prediction of physical appearance from DNA and is a technique being pioneered by Virginia-based Parabon Nanolabs.

The technology can be used to generate leads in criminal cases where there are no suspects or database hits, or to help identify remains, for example.

Samples can be potentially taken from as little as a fingerprint.

Parabon’s Snapshot Forensic system is said to be able to accurately predict genetic ancestry, eye colour, hair colour, skin colour, freckling, and face shape in individuals from any ethnic background.

Each prediction is presented with a ‘measure of confidence’.

As an example, the test can say a person has green eyes with 61 per cent confidence, green or blue with 79 per cent confidence, and that they definitely don’t have brown eyes, with 99 per cent confidence.

Based on ancestry, and other markers, the test also creates a likely facial shape.

From all of this information, it builds a computer generated e-fit.

And the test will predict how two people are related, as distant as third cousins, and great-great-great-great-grandparents.

‘DNA carries the genetic instruction set for an individual’s physical characteristics, producing the wide range of appearances among people,’ explained Parabon Nanolabs.

‘By determining how genetic information translates into physical appearance, it is possible to “reverse-engineer” DNA into a physical profile.

‘Snapshot reads tens of thousands of genetic variants from a DNA sample and uses this information to predict what an unknown person looks like.’

The project was supported with funding from the the US Department of Defense (DoD).

Samples can be taken from as little as a fingerprint. Parabon's Snapshot Forensic system is said to be able to accurately predict genetic ancestry, eye colour, hair colour, skin colour, freckling, and face shape in individuals from any ethnic background (example pictured).

Samples can be taken from as little as a fingerprint. Parabon’s Snapshot Forensic system is said to be able to accurately predict genetic ancestry, eye colour, hair colour, skin colour, freckling, and face shape in individuals from any ethnic background (example pictured).

Each prediction is presented with a ‘measure of confidence’. As an example, the test can say a person has green eyes with 61 per cent confidence, green or blue with 79 per cent confidence, and that they definitely don’t have brown eyes, with 99 per cent confidence. A series of example charts is pictured.

Each prediction is presented with a ‘measure of confidence’. As an example, the test can say a person has green eyes with 61 per cent confidence, green or blue with 79 per cent confidence, and that they definitely don’t have brown eyes, with 99 per cent confidence. A series of example charts is pictured.

Ellen McRae Greytak, Parabon’s director of bioinformatics told Popular Science that the system has been used in 10 cases across the US, and the first department to release a Snapshot report was the Columbia Police Department.

It produced a profile for a ‘person of interest’ in the murder of 25-year-old Candra Alston and her daughter Malaysia Boykin in 2011. (Investigators in South Carolina are hoping the DNA technique could lead to to a breakthrough in the unsolved murder case of Malaysia Boykin, three, (left) and her mother Candra Alston (right) in 2011).

The only piece of evidence left at the scene was an unspecified DNA sample.

There were no witnesses to the murder, so the local authorities turned to the forensic phenotyping and found the person was a male with dark-skinned, brown hair and brown eyes (profile pictured).

There were no witnesses to the murder, so the local authorities turned to the forensic phenotyping and found the person was a male with dark-skinned, brown hair and brown eyes (profile pictured).

There were no witnesses to the murder, so the local authorities turned to the forensic phenotyping and found the person was a male with dark-skinned, brown hair and brown eyes.

Mark Vinson, a cold case investigator with the Columbia police department, said that more than 200 people were interviewed in connection with the deaths.

Around 150 of them submitted their DNA – but none matched the sample left at the scene.

 

Ancillary:

FIND LONG-LOST RELATIVES USING YOUR DNA

Family history site Ancestry has extended its AncestryDNA service – a home testing kit that unlocks the secrets of a person’s genetic ethnicity – to the UK.

The results can be cross-checked with millions of family trees to help people discover unknown relatives.

It uses microarray-based autosomal DNA testing, which looks at person’s entire genome at more than 700,000 locations using saliva.

Since it was released in 2012, AncestryDNA has been used by around 700,000 people.

All of these results have been stored on a secure, encrypted database, and each set of results is linked to a person’s individual Ancestry account and subsequent family tree.

AncestryDNA can help people identify relationships with unknown relatives through a list of possible DNA member matches.

 

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Arts, Drama

Lateral Thinking Drama: ‘Death on Kilimanjaro’…

– ‘Death on Kilimanjaro’ is a Lateral Thinking Fictional Drama. Use your thinking and problem-solving skills to solve this conundrum

SCENARIO

FOR AT LEAST THE TENTH TIME THAT DAY, Kurt was vanishing out of sight. “For Chrissake, Kurt, slow down!” Joey shouted.

Ahead of him on the narrow track, Kurt paused in his stride. He turned up, lip curled in an expression of contempt. “Can’t hack it, Joey? You go back if you want. I’m heading for the summit.”

“I don’t want to turn back. I just gotta…get my breath.” Joey felt suddenly dizzy. He sank to his knees. Kurt looked on, making no attempt to help.

“Great adventurer,” he said, making it sound like an obscenity. “I always knew you were a loser, Joey. Can’t even make it up Kilimanjaro. It’s barely six thousand metres. Nothing to an experienced mountaineer.”

Like you, I suppose, Joey thought sardonically, but he didn’t have the strength to argue. He had quickly realised that Kurt had never climbed a mountain in his life. He had approached this whole project like a Sunday afternoon stroll. Yet, so far, anyway, he seemed immune to the altitude sickness that befell almost anyone who tried to climb too quickly. Feeling sick, Joey groped in his jacket pocket for his Diamox tablets.

Kurt reached into his pocket as well. He took out a cigarette. “I’ll smoke this, Joey boy, then I’m going on. You can come with me, or you can head back. It’s your choice.”

It had all been very different two days ago when they had arrived in Tanzania. Although hot and tired from their long journey, they had both been full of excitement at the prospect of the adventure ahead. They spent their first night at the Hotel Marangu, a faded but still-elegant establishment which was presided over by two matronly Englishwomen. Over a meal of ‘Chicken Marangu’, they planned their assault on the mountain.

“Of course, most first-timers take the tourist trail,” Joey pondered. “But that’s the least scenic route…”

“Tourist trail?” Kurt slammed his glass down on the table, spilling his Pilsner beer. “Don’t make me laugh, Joey. We’re adventurers, for God’s sake, not tourists! We take the toughest route available.”

They settled on the Machame Trail. It wasn’t actually the toughest, but privately Joey figured it would be more than challenging. The hotel owners arranged climbing permits and the hire of a jeep. They also provided trail maps, and recommended the services of two local porters. Kurt wasn’t having that, though.

“Porters are for train stations,” he said. The older woman peered at him over her lorgnette. She pursed her lips, but said nothing.

Once the necessary arrangements had been made, they journeyed by jeep to the base of Africa’s highest mountain. The road wound through coffee fields and small forests of ferns and flowers. The heat was stifling, and Joey was glad when they reached their destination and could at last get out of the vehicle. They parked beside two other off-roaders and strapped on their rucksacks. Then, watched by a chattering tribe of tree monkeys, they began the hot and dusty five-hour trek through the forest to Machame Hut, where they had arranged to spend the night.

The next day the climb began in earnest. Leaving the hut early in order to make good progress before the sun grew too strong, they crossed a small valley, covered with exotic spring flowers. Then the landscape changed from forest to scrubland, littered with wild cactus plants. They crossed a river gorge and arrived, according to the map, at the Shira Plateau. The heat was intense, and on top of it Joey had a splitting headache. He knew it to be the first symptom of altitude sickness. More symptoms had swiftly followed.

Kurt finished his cigarette and ground it under his heel. He stared at Joey. “Well?”

Joey climbed to his feet. He took a deep breath and exhaled slowly. He still felt lousy, but his head had cleared. The Diamox had done its work…this time, anyway. “I’m all right,” he said. “Let’s take it steady, shall we?”

They climbed on, up the track that led to the summit. Joey still felt pretty wasted, but thought he might just manage this last stretch, as long as they could descend straight afterwards. Kurt stopped suddenly. “Look,” he said.

Joey followed his pointing arm. Some way below, two other climbers were making their way down the mountain on another trail. One looked up and waved. At this distance, it was hard to tell whether it was a man or a woman. Joey watched till they disappeared behind some rocks.

“Looks like they made it,” Joey said. “That’ll be us in a few…” He stopped, staring at his partner.

Kurt was panting heavily. His face was covered in beads of sweat. “What are you looking at?” he snarled. He turned and took a few steps, then stumbled and fell. His rucksack flew open, scattering clothing and utensils. Joey rushed over to him.

Kurt lay on his back, mouth open. “My chest!” He gasped like a fish out of water. “Oh God, Joey, it feels like it’s being crushed.”

Joey didn’t like this at all. This was more than plain altitude sickness. He tried to remember what the book had said about High Altitude Pulmonary Oedema. He was positive the crushed chest sensation was a sign. Fluid was building up in Kurt’s lungs. Unless he got back to lower altitudes quickly, death would most certainly follow. They had to return to the hut where they had stayed last night. But there was no way that Joey could, in his present state, get Kurt back there on his own.

“I’ll get help,” he said. Kurt, still gasping, didn’t reply. Joey went back to the place where they had watched the other climbers descending; however, by now, there was no sign of them. He walked on a little way, shouting, but there was no reply. He hurried back to check on Kurt who was, by now, unconscious. His own heart pounding, Joey felt Kurt’s wrist. There was still a faint pulse.

There was no alternative. Quickly, Joey located and launched their emergency flare. There was a loud report as it erupted in a ball of magnesium light that momentarily rivalled the African sun.

Although others saw the emergency signal, they were unable to help and within two minutes of launching the flare, both Kurt and Joey were dead. Why?

– Detection level of difficulty: 9

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Health, Medical, Science

Questions of Science: ‘Rubbing salt in to the wound’…

Health

Rubbing salt in the wound was a way of preventing infection. But how did it work?

Applying salt to a wound creates a highly saline environment, one in which it is difficult for microbes to grow. The high concentration gradient between the salt solution and the fluid inside bacterial cells makes it far more difficult for the microbes to extract water from the solution without using a lot more energy. As a result, the bacteria become placid and dehydrated and cannot function normally or proliferate.

Concentrated sugar solutions also have a dehydrating effect. This accounts for the extended shelf life of chutneys and preserves, and explains why honey can be used on wound dressings and, ironically, on bee stings as an antiseptic.

Blood is 83 per cent water. Because salt is hygroscopic, it absorbs water, accelerating the tendency for blood to clot and drying the wound. This helps deny microorganisms a favourable habitat. Saline solutions do generate osmotic pressure – it forces water out of microbes to equalise the salt concentration across their cell membranes. This can kill them, so salt acts as a disinfectant.

The stinging of the wound signals that salt does cause injury to the body. But in the absence of a better option at the time, killing a few healthy skin cells was deemed acceptable collateral damage when the alternative may have been a serious infection or possible death.

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