Geneticists Are Starting To Unravel Evolution’s Role In Mental Illness 

In a twisted form of a "soulmate" story, people are born in pairs where only their counterpart is able to kill them. If you kill your counterpart, you forfeit your own death and thus become immortal.

Mysterious DNA modification seen in stress response

With advances in genomics, scientists are discovering additional components of the DNA alphabet in animals. Do these unusual chemical modifications of DNA have a special meaning, or are they just signs that cellular machines are making mistakes?

Geneticists at Emory University School of Medicine led by Peng Jin, PhD have been studying a modification of DNA that is not well understood in animals: methylation of the DNA letter A (adenine). They’ve found that it appears more in the brain under conditions of stress, and may have a role in neuropsychiatric disorders.

The results were published on Oct. 24 in Nature Communications.

Methylation on the DNA letter C (cytosine) generally shuts genes off and is an important part of epigenetic regulation, a way for cells to change how the DNA code is read without altering the DNA letters themselves. Methylation describes a mark consisting of an extra carbon atom and three hydrogens: -CH3.

What if methylation appears on adenine? In bacteria, N6-methyladenine is part of how they defend themselves against invasion by phages (viruses that infect bacteria). The same modification was recently identified as present in the DNA of insects and mammals, but this epigenetic flourish has been awaiting a full explanation of its function.

Just to start, having that extra -CH3 jutting out of the DNA could get in the way of proteins that bind DNA and direct gene activity. For C-methylation, scientists know a lot about the enzymes that grab it, add it or erase it. For A-methylation, less is known.

“We found that 6-methyl A is dynamic, which could suggest a functional role,” Jin says. “That said, the enzymes that recognize, add and erase this type of DNA methylation are still mysterious.”

It does appear that the enzymes that add methyl groups to A when it is part of RNA are not involved, he adds.

First author Bing Yao, PhD, assistant professor of human genetics, recently established his own laboratory at Emory to examine these and other emerging parts of the DNA alphabet. Jin is vice chair of research in the Department of Human Genetics.

In the Nature Communications paper, Yao, Jin and their colleagues looked at the prefrontal cortex region of the brain in mice that were subjected to stress, in standard models for the study of depression (forced swim test and tail suspension test).

Under these conditions, the abundance of N6-methyladenine in the brain cells’ DNA rose four-fold, the scientists found. The DNA modification was detected with two sensitive techniques: liquid chromatography/mass spectrometry and binding to an antibody against N6-methyladenine. The peak abundance is about 25 parts per million, which isn’t that high - but it appears to be confined to certain regions of the genome.

The methyl-A modification tended to appear more in regions that were between genes and was mostly excluded from the parts of the genome that encode proteins. The loss of methyl-A correlates with genes that are upregulated with stress, suggesting that something removes it around active genes. There does seem to be some “cross talk” between A and C methylation, Jin adds.

Genes bearing stress-induced 6mA changes overlapped with those associated with neuropsychiatric disorders; a relationship that needs more investigation. The scientists speculate that aberrant 6mA in response to stress could contribute to neuropsychiatric diseases by ectopically recruiting DNA binding proteins.

Language is Learned in Brain Circuits that Predate Humans

It has often been claimed that humans learn language using brain components that are specifically dedicated to this purpose. Now, new evidence strongly suggests that language is in fact learned in brain systems that are also used for many other purposes and even pre-existed humans, say researchers in PNAS.

The research combines results from multiple studies involving a total of 665 participants. It shows that children learn their native language and adults learn foreign languages in evolutionarily ancient brain circuits that also are used for tasks as diverse as remembering a shopping list and learning to drive.

“Our conclusion that language is learned in such ancient general-purpose systems contrasts with the long-standing theory that language depends on innately-specified language modules found only in humans,” says the study’s senior investigator, Michael T. Ullman, PhD, professor of neuroscience at Georgetown University School of Medicine.

“These brain systems are also found in animals — for example, rats use them when they learn to navigate a maze,” says co-author Phillip Hamrick, PhD, of Kent State University. “Whatever changes these systems might have undergone to support language, the fact that they play an important role in this critical human ability is quite remarkable.”

The study has important implications not only for understanding the biology and evolution of language and how it is learned, but also for how language learning can be improved, both for people learning a foreign language and for those with language disorders such as autism, dyslexia, or aphasia (language problems caused by brain damage such as stroke).

The research statistically synthesized findings from 16 studies that examined language learning in two well-studied brain systems: declarative and procedural memory.

The results showed that how good we are at remembering the words of a language correlates with how good we are at learning in declarative memory, which we use to memorize shopping lists or to remember the bus driver’s face or what we ate for dinner last night.  

Grammar abilities, which allow us to combine words into sentences according to the rules of a language, showed a different pattern. The grammar abilities of children acquiring their native language correlated most strongly with learning in procedural memory, which we use to learn tasks such as driving, riding a bicycle, or playing a musical instrument. In adults learning a foreign language, however, grammar correlated with declarative memory at earlier stages of language learning, but with procedural memory at later stages.

The correlations were large, and were found consistently across languages (e.g., English, French, Finnish, and Japanese) and tasks (e.g., reading, listening, and speaking tasks), suggesting that the links between language and the brain systems are robust and reliable.

The findings have broad research, educational, and clinical implications, says co-author Jarrad Lum, PhD, of Deakin University in Australia.

“Researchers still know very little about the genetic and biological bases of language learning, and the new findings may lead to advances in these areas,” says Ullman. “We know much more about the genetics and biology of the brain systems than about these same aspects of language learning. Since our results suggest that language learning depends on the brain systems, the genetics, biology, and learning mechanisms of these systems may very well also hold for language.”

For example, though researchers know little about which genes underlie language, numerous genes playing particular roles in the two brain systems have been identified. The findings from this new study suggest that these genes may also play similar roles in language. Along the same lines, the evolution of these brain systems, and how they came to underlie language, should shed light on the evolution of language.

Additionally, the findings may lead to approaches that could improve foreign language learning and language problems in disorders, Ullman says.

For example, various pharmacological agents (e.g., the drug memantine) and behavioral strategies (e.g., spacing out the presentation of information) have been shown to enhance learning or retention of information in the brain systems, he says. These approaches may thus also be used to facilitate language learning, including in disorders such as aphasia, dyslexia, and autism.

“We hope and believe that this study will lead to exciting advances in our understanding of language, and in how both second language learning and language problems can be improved,” Ullman concludes.

No specific external funding supported the work. The authors report having no personal financial interests related to the study.

The reason aliens have not invaded Earth is due to our television transmission. Since they have no concept of televised entertainment, they view everything seen as fact.

Dutch “Cuddly Owl” finally caught on video. This bird has been cuddling the citizens of this town for a while. It likes to land and stomp on people’s heads.

Watch the video

Carl Sagan, who would’ve been 83 today, on the power of books and why reading is essential for democracy. 

Este mes

Siento una soledad frio y terrible sin el calor de tu corazon,

La culpa fue mia, pero me duele sin tu amor

Quisiera haberte dicho esto el 2 de este mes, pero me dolia demasiado escribirlo

Perdi el amor de alguien increible y maravillosa, y honestamente no se que hacer sin ti.

Puedo decir todo esto ahora, porque ya te estas alejando de mi, y aunque lo lamento, yo se que es lo mejor. 

Quiero ser mejor, porque algun dia, en algun futuro, yo espero encontrate y amarte otravez. Y cuando ese dia ocurre, espero que tu tambien quieras lo mismo. 

Te amo con una furia y dolor y no puedo explicar.

Espero que estes contenta, amor, y aunque ya no lo crees por la manera que he estado actuando, te extrano, nada va cambiar eso. 

Human beings are able to use magic but only through a physical medium, such as a specific type of stone or plant and in some cases even animals. Usable mediums vary from person to person, and most people discover theirs by the time they’re teenagers. You’re now legally an adult but still haven’t found your medium. You’re beginning to think that you can’t use magic at all until a terrible encounter leads you to the horrifying revelation that your medium is human flesh.

Some sketches of the wild Raven while he is still in the park, he is a joy to sit with and draw. Even if he tries to steal my sketchbook at every opportunity. 

You punch in a date, and activate the time machine. There’s a flash of light, and you black out.

You awaken in what looks like a hi-tech hospital, with people walking around, conversing in a language you’ve never heard before. One person walks over to you, and says, in fluent English; “Well, you’ve managed to not only travel several thousand years into the past, but you’ve also managed to get into a timeline that honestly shouldn’t exist anymore. So, how do you feel?”