Posts Tagged ‘Genetics’

How to sequence the human genome

December 13, 2013

Your genome, every human’s genome, consists of a unique DNA sequence of A’s, T’s, C’s and G’s that tell your cells how to operate. Thanks to technological advances, scientists are now able to know the sequence of letters that makes up an individual genome relatively quickly and inexpensively.

Myths and misconceptions about evolution

July 31, 2013

How does evolution really work? Actually, not how some of our common evolutionary metaphors would have us believe. For instance, it’s species, not individual organisms, that adapt to produce evolution, and genes don’t “want” to be passed on — a gene can’t want anything at all!

‘Hulk’ Protein found

November 25, 2012

So you want to be muscular, buff, ripped, but you don’t want to have to work for it. Who does? Well here’s some good news, researchers have identified a “Hulk” protein that could give you crazy muscle mass with no effort on your part.

Grb10 is the protein in question, and researchers have found that disrupting the gene responsible for it can cause crazy boosts in muscle mass. That’s right, it seems that you need to get rid of it, not get more of it. In the study a group of mice with a disrupted Grb10 gene were far more muscular than their control counterparts, both at birth and during adulthood.

There are, of course, some caveats. In this study, the whole beefcake-ifying process started in the womb, so there’s no hope you could get the same treatment. These are also mice, not men. Nonetheless, this all points to an important protein that, in the future, could be extremely valuable in the treatment of people with muscle-wasting diseases. Learn more here or here.

Human Genome Is Much More Than Just Genes

November 8, 2012

For the past decade, scientists have been working on the assumption that 20,000 genes, less than 2 per cent of the total genome, underpin human biology. But a massive international project called ENCODE has revealed that plenty of the remaining 98 per cent, once tossed aside as “junk DNA”, is in fact incredibly important.

In fact, the project — known more formally as the Encyclopedia of DNA Elements — reveals that 80 per cent of that “junk DNA” is biochemically active. Add to that the fact that large stretches of DNA that appeared to serve no purpose actually contain over 400,000 regulators that help activate or silence genes, and the scientific community is surprised to say the least.

The findings will shake up biology for good, and are already starting to help scientists better understand disease. It will, however, take a long time for scientists to get to grips with the vast quantities of information this research yields. Learn more here or here.

50,000 year old human genome sequenced

November 6, 2012

In a stunning technical feat, an international team of scientists has sequenced the genome of an archaic Siberian girl 31 times over, using a new method that amplifies single strands of DNA. The sequencing is so complete that researchers have as sharp a picture of this ancient genome as they would of a living person’s, revealing, for example that the girl had brown eyes, hair, and skin.

That precision allows the team to compare the nuclear genome of this girl, who lived in Siberia’s Denisova Cave more than 50,000 years ago, directly to the genomes of living people, producing a “near-complete” catalog of the small number of genetic changes that make us different from the Denisovans, who were close relatives of Neandertals.

A tiny finger bone from Denisova Cave

Ironically, this high-resolution genome means that the Denisovans, who are represented in the fossil record by only one tiny finger bone and two teeth, are much better known genetically than any other ancient human—including Neandertals, of which there are hundreds of specimens. Learn more here.

DNA: The Ultimate Hard Drive

October 29, 2012

When it comes to storing information, hard drives don’t hold a candle to DNA. Our genetic code packs billions of gigabytes into a single gram. A mere milligram of the molecule could encode the complete text of every book in the Library of Congress and have plenty of room to spare. All of this has been mostly theoretical—until now. In a new study, researchers stored an entire genetics textbook in less than a picogram of DNA—one trillionth of a gram—an advance that could revolutionize our ability to save data.

The scientists encoded the 53,400-word book, 11 JPG images and a JavaScript program – amounting to 5.27 million bits of data in total – into sequences of DNA. If they were able to upscale the process this would equate to 5.5 petabits of data — around 700 terabytes — in a single gram of DNA.

Just think about it for a moment: One gram of DNA can store 700 terabytes of data. That’s 14,000 50-gigabyte Blu-ray discs… in a droplet of DNA that would fit on the tip of your pinky. To store the same kind of data on hard drives — the densest storage medium in use today — you’d need 233 3TB drives, weighing a total of 151 kilos. Learn more here, here, here or here.

Whole fetal genome sequenced before birth

August 19, 2012

The day when you can sequence your baby’s genome before it is born might not be too far away. Researchers have reconstructed the genome of a fetus without touching it. Instead, they used both parents’ genomes and free-floating fetal DNA, which circulates in the mother’s blood.

It may be at least five years before this type of test reaches the clinic and everyday use. By then, the price of the technology should have dropped. This current sequencing cost about $50,000 to perform.

The fact that it’s still a way off in the future is good considering the legal and ethical complications of parents having the ability to see every disease and trait their child will have before it is born. Learn more here or here.

Animations of unseeable biology

August 4, 2012

Drew Berry is one of the world’s foremost animators working in biomedical visualisation. He has concentrated much of his work on cellular visualisation – animating the behaviour, dynamics and physical properties of DNA, bio-molecules and proteins. Here he explains his work:

To see more truly amazing animations created by Drew, go here or here.

Your DNA Changes As You Age

August 3, 2012

While our bodies age, scientists believe that our DNA remains constant. New research, however, reveals that subtle chemical changes occur to our DNA as we age, even though its sequence remains constant — and it could explain why the risk of developing diseases increases as we get older.

DNA is made up of four basic chemical building blocks called adenine, thymine, guanine and cytosine (A, T, G and C). It’s the sequences of those chemicals in a strand of DNA that determines what function a gene has, and one of the ways the resulting genes are controlled is a process called methylation. That just means that a methyl group — one carbon atom and three hydrogen atom — bonds to part of the DNA and subtly change its function.

In a newborn baby, 73 per cent of cytosine nucleotides were methylated, while in centenarians that figure rose to 80.5 per cent. An intermediary example, taken from a 26-year-old male subject, exhibited 78 per cent methylation. It’s not clear why it happens, but the researchers speculate that it could be due to extremely subtle age-related changes to the DNA.

But what does it all mean? Well, taking a closer look at the samples, the researchers discovered that a third of the methylated groups that were different in the elderly compared to the young are already known to be linked to cancer risk.

If you think about the DNA strand as “hardware” and the added methyl groups as “software” — which isn’t actually a bad analogy — you can think of the inappropriately placed methyl groups as software bugs that accumulate with age. It’s just that, for humans, those bugs lead to increased risk of terminal disease. Fortunately, these kinds of findings should help scientists troubleshoot our internal apps. Learn more here, here or here.

Tomatoes Sequenced and also Lost Their Taste

July 22, 2012

The genome sequence of one of the world’s highest-value salad plants — the tomato — was decoded by an international team of scientists earlier in the year.

The tomato (Solanum lycopersicum) is an increasingly popular fruit, with 145.8 million tonnes produced globally in 2010. Learn more here or here.

On top of this, another study has revealed that decades of breeding the fruits for uniform color have robbed them of a gene that boosts their sugar content.

The finding is a massive advance in our understanding of tomato fruit development and ripening.

Farmers pluck the fruits from the vine before they are ripe, and for about 70 years breeders have selected tomatoes that are uniformly light green at that time. This makes it easier to spot the tomatoes that are ready to be harvested and ensures that, by the time they hit supermarket shelves, the fruits glow with an even red color. Wild varieties, in contrast, have dark green shoulders, and that makes it harder to determine the right time to harvest.

Unfortunately, while the light green mutation is beneficial to farmers, it’s not such a sweet deal for consumers. It seems those tomatoes have less sugar and don’t taste quite as good. Learn more here.


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