Posts tagged DNA

In what scientists call the biggest breakthrough in genetics since the unraveling of the human genome, a massive research effort now shows how the genome works.The human genome contains 3 billion letters of code containing a person’s complete genetic makeup. The biggest surprise is that most of the DNA in the genome which had been called “junk DNA” because it didn’t seem to do anything turns out to play a crucial role. While only 2% of the genome encodes actual genes, at least 80% of the genome contains millions of “switches” that not only turn genes on and off, but also tell them what to do and when to do it.

Eleven years ago, the Human Genome Project discovered the blueprint carried by every cell in the body. The new ENCODE project now has opened the toolbox each cell uses to follow its individual part of the blueprint. The effort is the work of more than 400 researchers who performed more than 1,600 experiments. The genome, with its 3-billion-letter code, reads from beginning to end like a book. But in real life, the genome isn’t read like a book. The ENCODE data shows it’s an intricate dance, with each step carefully choreographed.

(Source: futurenow321)

A massive DNA database has generated a map of the genetic switches which impact everything from hair loss to cancer and opened the door to revolutionary treatments for a host of deadly diseases, researchers said Wednesday.

“This is a major step toward understanding the wiring diagram of a human being,” said lead researcher Michael Snyder of Stanford University.

The Encyclopedia of DNA Elements  or ENCODE has enabled scientists to assign specific biological functions for 80 percent of the human genome and has helped explain how genetic variants affect a person’s susceptibility to disease.

It also exposed previously hidden connections between seemingly unrelated diseases such as asthma, lupus and multiple sclerosis which were found to be linked to specific genetic regulatory codes for proteins that regulate the immune system.

(Source: futurenow321)

Exactly why James Markam is alive and well is a bit of a mystery. The octogenarian has lost four siblings to cancer, heart disease and emphysema, all before they reached the age of 62. Yet the retired airline executive recalls only one bout of sickness, culminating with a chest cold, 50 years ago.

Scientists are taking a deep look at Markam’s genetics to see if there’s something protecting him from illnesses that affect others his age, such as Alzheimer’s, cancer, diabetes and heart disease.

Markam, 83, of San Diego is one of more than 1,300 individuals identified as having what Eric Topol, director of the Scripps Translational Science Institute, called “Teflon-coated” genes.

“We think it’s in the genome in these individuals,” said Topol, who is leading research of healthy older people called the Wellderly Study at the institute. “You don’t see any environmental thing that would be explaining this.”

The study expects to have the first set of participants’ genes sequenced by the end of the year, said Cliff Reid, chief executive officer of Mountain View’s Complete Genomics Inc., which is doing the work for free.

Scientists and pharmaceutical companies are closely watching Scripps’ research project and others like it, eager for clues that may help them develop new treatments to ward off diseases that have long afflicted the elderly.

For drug companies such as Merck & Co. and Eli Lilly & Co., the hope is that the research will lead to the creation of billion-dollar blockbuster therapies.

The human genome is a transcript of an individual’s DNA code containing the instructions for making cells in the body. Scientists say the genome may provide keys to understanding health and disease.

The projects reflect researchers’ evolving views of how genetic mutations cause disease. While scientists once thought common genetic variants were responsible for many common diseases, recent research has changed that view.

Instead, combinations of the millions of rare variants are the more likely culprits behind widespread ailments, making them difficult to identify.

Creating a clean map of a healthy genome that can be quickly compared with the DNA that makes a person vulnerable to illness, the thinking goes, will allow researchers to more readily search for the roots of disease.

“What it does is accelerate discoveries of the basics of human disease,” Reid said. “The Wellderly data set promises to offer a superior set of harmless variations; that will enable researchers to more effectively separate the harmless variations from the disease-causing variations.”

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At the time, the mother was just 18 weeks into the pregnancy.

The doctors said the findings, reported in Science Translational Medicine, could eventually lead to foetuses being screened for thousands of genetic disorders in a single and safe test.

However, they also caution it would raise “many ethical questions”.

The scientists at the University of Washington used pieces of the foetus’ DNA which naturally float around in the pregnant woman’s blood.

(Source: futurenow321)

Synthetic biologists have long sought to devise biological data-storage systems because they could be useful in a variety of applications, and because data storage will be a fundamental function of the digital circuits that the field hopes to create in cells.Rewritable biological memory circuits have been made previously, for instance from systems of transcription factors, which can be used to shut gene expression on or off in a cell. In such systems, once the memory state of the circuit is set, it can be erased and encoded with a new memory state, as is done in everyday devices such as personal computers.

Endy’s group attempted to create a rewritable memory system by splicing genetic elements from a bacteriophage a bacterium-infecting virus — into the DNA of the bacterium Escherichia coli. “What Drew’s group can do that others haven’t demonstrated is the ability to cycle the memory element over and over, kind of like you can write a bit to a hard drive, read it and change it back over and over again,” says synthetic biologist Eric Klavins of the University of Washington in Seattle.

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A copyediting error appears to be responsible for critical features of the human brain that distinguish us from our closest primate kin, new research finds. When tested out in mice, researchers found this “error” caused the rodents’ brain cells to move into place faster and enabled more connections between brain cells.When any cell divides, it first copies its entire genomeDuring this process, it can make errors. The cell usually fixes errors in the DNA. But when they aren’t fixed, they become permanent changes called mutations, which are sometimes hurtful and sometimes helpful, though usually innocuous.

The researchers studied one specific gene, called SRGAP2, which they think has been duplicated at least twice during the course of human evolution, first about 3.5 million years ago and then again about 2.5 million years ago.The second, more recent, duplication seems to be incomplete, with only part of the gene being duplicated. The researchers think this partially duplicated gene is able to interfere with the actions of the original, ancestral copy of SRGAP2. When the researchers added  the partially duplicated gene copy to the mouse genome (mice don’t normally have it) it seemed to speed the migration of brain cells during development, which makes brain organization more efficient.These cells that expressed the incomplete duplication of SRGAP2 also had more “spines” — knoblike extensions on the cell surface that connect with other brain cells, which make them look more like human brain cells.

Interestingly, the incomplete copy of the gene seems to have showed up just as the extinct hominin Australopithecus made room for the genus Homo, which led to modern humans. That’s also when the brains of our ancestors began to expand and when dramatic changes in cognitive abilities are likely to have emerged.

(Source: futurenow321)

As cold cases go, it does not get much colder than Ötzi the Iceman, whose body was found frozen solid in the Italian Alps 5,300 years after he died from an arrow wound.

Since he was discovered by trekkers in 1991, scientists have mapped his DNA and figured out everything from what ailments he suffered from (Lyme disease and a weak heart) to the last meal he ate (venison and ibex) before he was shot in the back, probably by an enemy tribesman.

Now, using advancednanotechnology, they have located traces of Ötzi’s blood, the oldest blood sample ever retrieved. The discovery sheds new light on his death and may change the way police study blood found at modern crime scenes.

Using an atomic microscope and a spectroscope, an Italo-German team found tiny traces of blood similar to modern-day blood around the arrow wound and a cut to Ötzi’s hand.

The team also found fibrin, a protein involved in blood clotting, in the arrow wound. “Fibrin is produced by the body at the moment of wounding and later replaced during the healing process,” Zink said. “What we found shows he died within 30 minutes of being shot.”

(Source: futurenow321)

Analyzing DNA from four ancient skeletons and comparing it with thousands of genetic samples from living humans, a group of Scandinavian scientists reported that agriculture initially spread through Europe because farmers expanded their territory northward, not because the more primitive foragers already living there adopted it on their own.

The genetic profiles of three Neolithic hunter-gatherers and one farmer who lived in the same region of modern-day Sweden about 5,000 years ago were quite different — a fact that could help resolve a decades-old battle among archaeologists over the origins of European agriculture, said study leader Mattias Jakobsson, a population geneticist at Uppsala University in Sweden.

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 Scientists have identified a new mechanism by which colon cancer develops. The breakthrough discovery was accomplished by a team of researchers at Case Western Reserve University School of Medicine. By focusing on segments of DNA located between genes, or so-called “junk DNA,” the team has uncovered a set of master switches, i.e., gene enhancer elements, that turn “on and off” key genes whose altered expression is defining for colon cancers.

(Source: futurenow321)