In a world dominated by magical thinking, superstition and religion, give yourself the benefit of doubt. This is one skeptic's view of the Universe.

"Tell people there’s an invisible man in the sky who created the universe, and the vast majority believe you. Tell them the paint is wet, and they have to touch it to be sure."

-George Carlin

“If people are good only because they fear punishment, and hope for reward, then we are a sorry lot indeed”.

-Albert Einstein

“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”

-Carl Sagan

The person who is certain, and who claims divine warrant for his certainty, belongs now to the infancy of our species. It may be a long farewell, but it has begun and, like all farewells, should not be protracted.

-Christopher Hitchens

 

academicatheism:

Evolution of life’s operating system revealed in detail
The evolution of the ribosome, a large molecular structure found in the cells of all species, has been revealed in unprecedented detail in a new study.
Around 4 billion years ago, the first molecules of life came together on the early Earth and formed precursors of modern proteins and RNA. Scientists studying the origin of life have been searching for clues about how these reactions happened. Some of those clues have been found in the ribosome.
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academicatheism:

Evolution of life’s operating system revealed in detail

The evolution of the ribosome, a large molecular structure found in the cells of all species, has been revealed in unprecedented detail in a new study.

Around 4 billion years ago, the first molecules of life came together on the early Earth and formed precursors of modern proteins and RNA. Scientists studying the origin of life have been searching for clues about how these reactions happened. Some of those clues have been found in the ribosome.

Continue Reading

sciencesoup:

Nucleic Acids
Nucleic acids are the “genetic software” of the cell, allowing organisms to pass on their complex components to the next generation. You might know them better as DNA (deoxyribonucleic acid) or RNA (ribonucleic acid): the macromolecules responsible for storing and transmitting hereditary information. They’re the reason you have blonde hair, or long fingers, or a gigantic nose. Without them, no organism could produce offspring, so they’re essential for all life.
Nucleic acids are made up of a chain of monomers called nucleotides, which are in turn made up of five-carbon sugars, a nitrogenous base, and one or more phosphate groups. That might seem like an extra level of complication, but we need to know this to understand their structure.
Consider, for example, a DNA molecule:

The two strands running down on either side are called the molecule’s “sugar phosphate backbone”, which are connected in the middle by nitrogenous bases that pair up to the adjacent strand.There are four kinds of bases: Adenine and Guanine, which are purines, and Cytosine and Thymine, which are pyrimidines. In RNA, Thymine is replaced with Uracil (a pyrimidine). Purines have two rings and pyrimidines have one ring, so the groupings just refer to structure.

(Source)
The bases are almost always shortened to A, G, C, T & U. Their order determines how life is built—they encode a sequence of amino acids, which instruct how proteins are built. We’ll learn more about later.
Nitrogenous bases are hydrophobic, meaning they hate water. This is crucial to the structure of the DNA, because the strands are oriented so the bases face each other rather than the outside world, protecting them from water. The bases pair together using hydrogen bonds—purines always pair with pyrimidines, so A pairs with T (U in RNA), and C with G.  In any given DNA molecule, the amount of A equals the amount of T, and the amount of C equals the amount of G. This is important because it maintains a uniform diameter for the helix of DNA.

The person who realised this equality was Austrian biochemist Erwin Chargaff, and he was a contemporary of American biologist James Watson and English physicist Francis Crick, who you might have heard of. In 1953, they were the first to publish the spiralling, double-helix structure of DNA. (See my article on Rosalind Franklin for the reason I’m not a fan of Watson and Crick.)
DNA strands have a polarity, meaning they have a direction—strands are always synthesised from the 5’ (said “five prime”) end to the 3’ end. I’ll talk a whole lot more about how this happens later on. The important thing to know now is that when two strands are connected in a DNA molecule, they run antiparallel, like this:
So, what about an RNA molecule?
For starters, DNA is located in a different place to RNA:

RNA only has a single strand, and it’s made from a different sugar: ribose instead of deoxyribose. Basically, this means it has one more OH group). RNA also has a completely different function. While DNA is the blueprint for life, RNA is the guy who actually gets things done. Different types of RNA are specialised for different functons: mRNA (messenger RNA) carries the blueprints between DNA and ribosomes in order to make proteins; rRNA (ribosomal RNA) essentially makes up the ribosomes; and tRNA (transfer RNA) carries amino acids into the ribosome for synthesis into proteins.
In summary: nucleic acids are made up sugars, phosphate groups, and nitrogenous bases, and their function is to encode, transmit, and express hereditary information. Next article, we’ll take a look at how scientists learned that nucleic acids are the genetic material of life.
Body images sourced from Wikimedia Commons
Further resources: Structure of Nucleic Acids at Educationportal

sciencesoup:

Nucleic Acids

Nucleic acids are the “genetic software” of the cell, allowing organisms to pass on their complex components to the next generation. You might know them better as DNA (deoxyribonucleic acid) or RNA (ribonucleic acid): the macromolecules responsible for storing and transmitting hereditary information. They’re the reason you have blonde hair, or long fingers, or a gigantic nose. Without them, no organism could produce offspring, so they’re essential for all life.

Nucleic acids are made up of a chain of monomers called nucleotides, which are in turn made up of five-carbon sugars, a nitrogenous base, and one or more phosphate groups. That might seem like an extra level of complication, but we need to know this to understand their structure.

Consider, for example, a DNA molecule:

image

The two strands running down on either side are called the molecule’s “sugar phosphate backbone”, which are connected in the middle by nitrogenous bases that pair up to the adjacent strand.There are four kinds of bases: Adenine and Guanine, which are purines, and Cytosine and Thymine, which are pyrimidines. In RNA, Thymine is replaced with Uracil (a pyrimidine). Purines have two rings and pyrimidines have one ring, so the groupings just refer to structure.

image

(Source)

The bases are almost always shortened to A, G, C, T & U. Their order determines how life is built—they encode a sequence of amino acids, which instruct how proteins are built. We’ll learn more about later.

Nitrogenous bases are hydrophobic, meaning they hate water. This is crucial to the structure of the DNA, because the strands are oriented so the bases face each other rather than the outside world, protecting them from water. The bases pair together using hydrogen bonds—purines always pair with pyrimidines, so A pairs with T (U in RNA), and C with G.  In any given DNA molecule, the amount of A equals the amount of T, and the amount of C equals the amount of G. This is important because it maintains a uniform diameter for the helix of DNA.

image

The person who realised this equality was Austrian biochemist Erwin Chargaff, and he was a contemporary of American biologist James Watson and English physicist Francis Crick, who you might have heard of. In 1953, they were the first to publish the spiralling, double-helix structure of DNA. (See my article on Rosalind Franklin for the reason I’m not a fan of Watson and Crick.)

DNA strands have a polarity, meaning they have a direction—strands are always synthesised from the 5’ (said “five prime”) end to the 3’ end. I’ll talk a whole lot more about how this happens later on. The important thing to know now is that when two strands are connected in a DNA molecule, they run antiparallel, like this:

So, what about an RNA molecule?

For starters, DNA is located in a different place to RNA:

image

RNA only has a single strand, and it’s made from a different sugar: ribose instead of deoxyribose. Basically, this means it has one more OH group). RNA also has a completely different function. While DNA is the blueprint for life, RNA is the guy who actually gets things done. Different types of RNA are specialised for different functons: mRNA (messenger RNA) carries the blueprints between DNA and ribosomes in order to make proteins; rRNA (ribosomal RNA) essentially makes up the ribosomes; and tRNA (transfer RNA) carries amino acids into the ribosome for synthesis into proteins.

In summary: nucleic acids are made up sugars, phosphate groups, and nitrogenous bases, and their function is to encode, transmit, and express hereditary information. Next article, we’ll take a look at how scientists learned that nucleic acids are the genetic material of life.

Body images sourced from Wikimedia Commons

Further resources: Structure of Nucleic Acids at Educationportal

thenewenlightenmentage:

The Continuing Evolution of Genes
Each of us carries just over 20,000 genes that encode everything from the keratin in our hair down to the muscle fibers in our toes. It’s no great mystery where our own genes came from: our parents bequeathed them to us. And our parents, in turn, got their genes from their parents.
But where along that genealogical line did each of those 20,000 protein-coding genes get its start?
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thenewenlightenmentage:

The Continuing Evolution of Genes

Each of us carries just over 20,000 genes that encode everything from the keratin in our hair down to the muscle fibers in our toes. It’s no great mystery where our own genes came from: our parents bequeathed them to us. And our parents, in turn, got their genes from their parents.

But where along that genealogical line did each of those 20,000 protein-coding genes get its start?

Continue Reading

tedx:

At TEDxYouth@Manchester, genetics researcher Dan Davis introduces the audience to compatibility genes — key players in our immune system’s functioning, and the reason why it’s so difficult to transplant organs from person to person: one’s compatibility genes must match another’s for a transplant to take.

To learn more about these fascinating genes, watch the whole talk here»

(Images from Davis’s talk, Drew Berry’s animations, and the TED-Ed lessons A needle in countless haystacks: Finding habitable worlds - Ariel Anbar and How we conquered the deadly smallpox virus - Simona Zompi)

mothernaturenetwork:

Space dust is filled with building blocks of lifeGrit from rare space rocks may be filled with the tiny seeds of life, but sensitive techniques are needed to extract the proof of these cosmic seeds.

mothernaturenetwork:

Space dust is filled with building blocks of life
Grit from rare space rocks may be filled with the tiny seeds of life, but sensitive techniques are needed to extract the proof of these cosmic seeds.

wildcat2030:

Phobias may be memories passed down in genes from ancestors
 Memories may be passed down through generations in DNA in a process that may be the underlying cause of phobias 
Memories can be passed down to later generations through genetic switches that allow offspring to inherit the experience of their ancestors, according to new research that may explain how phobias can develop. Scientists have long assumed that memories and learned experiences built up during a lifetime must be passed on by teaching later generations or through personal experience. However, new research has shown that it is possible for some information to be inherited biologically through chemical changes that occur in DNA. Researchers at the Emory University School of Medicine, in Atlanta, found that mice can pass on learned information about traumatic or stressful experiences – in this case a fear of the smell of cherry blossom – to subsequent generations. The results may help to explain why people suffer from seemingly irrational phobias – it may be based on the inherited experiences of their ancestors. (via Phobias may be memories passed down in genes from ancestors - Telegraph)

wildcat2030:

Phobias may be memories passed down in genes from ancestors

Memories may be passed down through generations in DNA in a process that may be the underlying cause of phobias

Memories can be passed down to later generations through genetic switches that allow offspring to inherit the experience of their ancestors, according to new research that may explain how phobias can develop. Scientists have long assumed that memories and learned experiences built up during a lifetime must be passed on by teaching later generations or through personal experience. However, new research has shown that it is possible for some information to be inherited biologically through chemical changes that occur in DNA. Researchers at the Emory University School of Medicine, in Atlanta, found that mice can pass on learned information about traumatic or stressful experiences – in this case a fear of the smell of cherry blossom – to subsequent generations. The results may help to explain why people suffer from seemingly irrational phobias – it may be based on the inherited experiences of their ancestors. (via Phobias may be memories passed down in genes from ancestors - Telegraph)

thenewenlightenmentage:

Researchers find unexpected genetic mosaic in the brain
Scientists at the University of Virginia and elsewhere have discovered that nerve cells in the brain are unexpectedly varied in their genetic makeup, a surprising finding that may help explain schizophrenia, depression, bipolar disorder, autism and other such conditions thought to be genetically linked but not yet tied to a single gene.
Researchers at U.Va.’s School of Medicine and their collaborators found that up to 41 percent of the neurons they examined displayed at least one significant variation in DNA – a percentage far greater than anticipated. This variation could be in the form of either a duplication or a deletion in the genetic code. A deletion could lead to reduced expression of the affected genes, while a duplication could lead to greater expression.
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thenewenlightenmentage:

Researchers find unexpected genetic mosaic in the brain

Scientists at the University of Virginia and elsewhere have discovered that nerve cells in the brain are unexpectedly varied in their genetic makeup, a surprising finding that may help explain schizophrenia, depression, bipolar disorder, autism and other such conditions thought to be genetically linked but not yet tied to a single gene.

Researchers at U.Va.’s School of Medicine and their collaborators found that up to 41 percent of the neurons they examined displayed at least one significant variation in DNA – a percentage far greater than anticipated. This variation could be in the form of either a duplication or a deletion in the genetic code. A deletion could lead to reduced expression of the affected genes, while a duplication could lead to greater expression.

Continue Reading

thenewenlightenmentage:

Wide range of differences, mostly unseen, among humans
No two human beings are the same. Although we all possess the same genes, our genetic code varies in many places. And since genes provide the blueprint for all proteins, these variants usually result in numerous differences in protein function. But what impact does this diversity have? Bioinformatics researchers at Rutgers University and the Technische Universitaet Muenchen (TUM) have investigated how protein function is affected by changes at the DNA level. Their findings bring new clarity to the wide range of variants, many of which disturb protein function but have no discernible health effect, and highlight especially the role of rare variants in differentiating individuals from their neighbors.
Continue Reading

thenewenlightenmentage:

Wide range of differences, mostly unseen, among humans

No two human beings are the same. Although we all possess the same genes, our genetic code varies in many places. And since genes provide the blueprint for all proteins, these variants usually result in numerous differences in protein function. But what impact does this diversity have? Bioinformatics researchers at Rutgers University and the Technische Universitaet Muenchen (TUM) have investigated how protein function is affected by changes at the DNA level. Their findings bring new clarity to the wide range of variants, many of which disturb protein function but have no discernible health effect, and highlight especially the role of rare variants in differentiating individuals from their neighbors.

Continue Reading

confrontingbabble-on:

Looking forward to, and enjoying simple pleasures…makes life all the sweeter

Right now is all there is.

confrontingbabble-on:

Looking forward to, and enjoying simple pleasures…makes life all the sweeter

Right now is all there is.

The language we speak, the shape of our skulls, even our ability to fight certain diseases, can be predicted with a remarkable degree of accuracy, just from our distance from Africa.

If there is life on Mars, it’s not too farfetched to believe that such Martian species may share genetic roots with life on Earth, based on RNA or DNA. That’s because more than 3.5 billion years ago, a blitz of meteors ricocheted around the solar system, passing material between the two fledgling planets. This may have left bits of Earth on Mars, and vice versa, creating a shared genetic ancestry between the two planets. Such a theory holds great appeal for Christopher Carr, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences. He’s building a DNA sequencer that he hopes will one day be sent to Mars, where it can analyze soil and ice samples for traces of DNA and other genetic material.

DNA Study Reveals Clues about Primate Evolution


…“Gathering this data is critical to understanding differences between great ape species and separating aspects of the genetic code that distinguish humans from other primates,” said co-first author Peter Sudmant, a graduate student at the University of Washington.

The analysis of great ape genetic diversity is likely to reveal ways that natural selection, population growth and collapse, geographic isolation and migration, climate and geological changes and other factors shaped primate evolution…

…The scientists also are looking for the genetic differences between humans and other great apes that might confer traits that are uniquely human. Those species’ differences may direct researchers to portions of the human genome associated with cognition, speech or behavior, providing clues to which mutations might underlie neurological diseases…

…Even though early human-like species were present at the same time as the ancestors of some present-day great apes, the researchers found that the evolutionary history of ancestral great ape populations was far more complex than that of humans.

Compared to our closest relatives, chimpanzees, human history appears “almost boring,” the researchers conclude. The last few million years of chimpanzee evolutionary history are fraught with population explosions followed by implosions demonstrating remarkable plasticity. The reasons for these fluctuations in chimpanzee population size long before our own population explosion are still unknown, however.

Source article

New life form found in Lake Vostok

A wholly new type of bacteria has been found in Lake Vostok in Antarctica by Russian scientists, according to reports.

The samples obtained from the underground lake in May 2012 contained a bacteria which bore no resemblance to existing types, said Sergei Bulat of the genetics laboratory at the Saint Petersburg Institute of Nuclear Physics.

"After putting aside all possible elements of contamination, DNA was found that did not coincide with any of the well-known types in the global database," he told RIA Novosti.

"We are calling this life form unclassified and unidentified," he added.

The discovery comes from samples collected in an expedition in 2012 where a Russian team drilled down to the surface of Lake Vostok, which is believed to have been covered by ice for more than a million years but has kept its liquid state.

Lake Vostok is the largest subglacial lake in Antarctica and scientists have long wanted to study its ecosystem. The Russian team last year drilled almost 2.34 miles to reach the lake and take the samples.

Bulat said that the interest surrounded one particular form of bacteria whose DNA was less than 86 per cent similar to previously existing forms.

"In terms of work with DNA this is basically zero. A level of 90 per cent usually means that the organism is unknown."

He said it was not even possible to find the genetic descendants of the bacteria.

"If this had been found on Mars everyone would have undoubtedly said there is life on Mars. But this is bacteria from Earth."

Bulat said that new samples of water would be taken from Lake Vostok during a new expedition in May.

"If we manage to find the same group of organisms in this water we can say for sure that we have found new life on Earth that exists in no database," Bulat said.

Source