Category: Genetics


What Can A Lizard Tell Us About Mental Health?

00Animal Behavior, Child Development, Epigenetics, Evolutionary Psychology, Featured news, Genetics, Mental Health, Parenting, Stress, Trauma December, 18

Source: Hayke Tjemmes at flickr, Creative Commons

A new study on lizards has found that, when exposed to stress, their responses can be passed down genetically. Scientists now believe there may be more to the process of heritability than once thought. This process is called “Transgenerational Stress Inheritance.”

As recently as 2011, most research did not examine the possibility that parental stress could affect sperm or egg cells. Since genes are transferred to offspring through these cells, anything that modifies them can have an impact on genetic expression in children. The idea that parents’ experiences prior to pregnancy can change gene expression and, therefore, affect offspring behaviour, is novel.

In the lizard study, researchers from Pennsylvania State University exposed young lizards to fire ants (a natural stressor) and compared stress levels to unexposed lizards. Interestingly, contact with the stressor did not affect the lizards’ behaviour later in life. But, their offspring had stronger stress reactions than offspring of lizards who had not been subjected to the ants.

Lead researcher Gail McCormick told PsyPost:

“Our work reveals that the stress experienced by an individual’s parents or ancestors may overshadow the stress that an individual faces within its lifetime. In this study, offspring of lizards from high-stress sites were more responsive to stress as adults, regardless of exposure to stress during their own lifetime.”

These findings suggest that, although early life stress may not manifest later in adulthood, the effects may be passed down to offspring, even if offspring are not directly exposed to the stressor.

A similar study involved researchers conditioning mice to associate the smell of cherries with a mild electric current. When the fragrance permeated the air, the mice were given a small electric shock. And so, the mice began to fear the scent even when the shock wasn’t administered. Even more fascinating was that offspring of these mice, as well as their offspring, experienced fear in the presence of the odor. The fear reaction occurred even though the later generations didn’t experience the conditioning process.

Of course, the question these studies pose is whether there is a similar effect in humans.

As recently reported in the Guardian newspaper, researchers from New York’s Mount Sinai School of Medicine compared the genes of direct descendants of Jews who were “interned in a Nazi concentration camp, witnessed or experienced torture or who had had to hide during the second world war” to the offspring of Jews living outside of Europe who were unharmed. The children of parents who experienced WWII trauma showed genetic changes and a greater risk of stress disorders. These were not present in the other children. The Guardian article stated:

“[The] new finding is [a] clear example in humans of the theory of epigenetic inheritance: the idea that environmental factors can affect the genes of your children.”

In other research, psychologist Margaret Keyes from the University of Minnesota and colleagues examined twins to determine if the behaviour of biological parents could affect offspring who were not raised by them. The study found that children of parents who smoked were more likely to be smokers, even if those children weren’t raised by the parents, and as such, did not have parental smoking behavior modeled to them. Scientists are still questioning, though, whether it’s parental behavior directly affecting these genes or a genetic predisposition to smoking being passed down for generations.

On the whole, these studies make the case that genetic changes can happen a lot faster than previously thought, within a few generations or even one generation. And, as reported in Science magazine, people can see evolution in real time:

“Now, thanks to the genomic revolution, researchers can actually track the population-level genetic shifts that mark evolution in action—and they’re doing this in humans. [Studies] show how our genomes have changed over centuries or decades…”

Research in this field is still new and is subject to several caveats. Perhaps the most important one is the complexity of human beings and their environments. Indeed, there may be too many variables that factor into the human experience for researchers to arrive at definitive conclusions.

But, these studies do suggest that individuals may be affected by the stress felt by ancestors in  before them. Further research is required to determine whether these findings are the result of transgenerational stress inheritance or an external factor that has yet to be considered.

– Andrei Nistor, Contributing Writer, The Trauma and Mental Health Report

– Chief Editor: Robert T. Muller, The Trauma and Mental Health Report.

-Copyright Robert T. Muller

This article was originally published on Psychology Today


The Making of a Murderer

00Child Development, Featured news, Genetics, Law and Crime, Parenting, Psychopathy July, 18

Source: sarahjgibson at DeviantArt, Creative Commons

In 1993, when Robert Thompson and Jon Venables from Liverpool, England were both 10 years of age, they killed a two-year-old boy. Thompson and Venables kidnapped the victim from a shopping centre, tortured him, and left him to die.

Stories like these raise many questions. Chief among them, how does something like this happen at all? Was it the result of bad parenting? The community certainly thought so, viewing the boys’ upbringing as the cause.

The trial had exposed evidence of domestic problems in both families. The judge stated that Thompson’s and Venable’s parents must take moral responsibility for their children’s actions. So members of the Thompson family had to assume new identities and go into hiding. They moved nine times to escape verbal and physical attacks. The Venables experienced similar threats.

In a recent interview with CNN, family therapist Tricia Ferrara put the onus on parents to understand when their child is in trouble. She said:

“All parents need a better understanding of child development so we can detect when the signals show a child may be moving in an anti-social direction.”

And a study conducted on the Columbine shootings, where two teenagers killed 12 students and a teacher at Columbine High School in Denver, suggested that the community saw parents as partly accountable for the murders.

There’s no doubt that parenting plays an enormous role in child development. Researchhas found that abuse, negative parenting, and prolonged malnutrition are linked to a proclivity toward physical violence.

But, there is also important research pointing to the role biology plays in predisposing some individuals to psychopathy, including violence. The BBC reported that neuroscientist Adrian Raine discovered a decrease in activity of the pre-frontal cortex in the brains of murderers, suggesting a genetic predisposition.

And, research by Elizabeth Cauffman and colleagues from the University of California found that good parenting doesn’t always lead to the outcomes we imagine. In fact, anti-social encouragement by a romantic partner was correlated with the highest level of offending in youth, even when warm relationships endured with parents.

In a TVO documentary Genetic Me, professor Daniel Nettle claimed that personality is stable throughout a person’s life. Individuals have tendencies for some things and not others. Nettle suggests that people are born with predispositions for certain personality traits. He adds, though, that the environment has some effect on bringing out theses inclinations, and that people can fight against them.

NPR reported that there are additional factors that play into a person’s development, perhaps explaining why not all children raised by the same parents are violent. Children in the same families have distinct personalities and varied interests that elicit different parenting. Plus, children experience independent social environments outside the home.

Perhaps the complexity of the matter is described best by neurobiologist James Fallon, who studies the brains of psychopathic killers. He explained in a TED Talk that an interaction occurs between environment and genetics. When presented with a particular brain image, he noted it was clearly a psychopath’s brain. What was most shocking—it was his own brain. Fallon, though, is not a killer, and had a happy upbringing. But, he has a family history of homicide. The first documented murder of a mother by a son was committed by a member of his family, several generations back.

Fallon said that, although some individuals, mostly male, have genes or brain damage that make them more susceptible to becoming murderers, their childhood experiences can make all the difference. For instance, the MAOA gene in particular can give rise to a violent individual if the gene is combined with experiences of brutality.

Where do murderers come from? Like all the big questions in mental health, an either-or perspective leaves little room for complexity. In the great genetics versus environment debate, the making of murderers—indeed, the making of us—requires that we look somewhere in-between.

–Anika Rak, Contributing Writer, The Trauma and Mental Health Report. 

–Chief Editor: Robert T. Muller, The Trauma and Mental Health Report.

Copyright Robert T. Muller.

This article was originally published on Psychology Today

Probiotics May Help Alleviate Autism Symptoms

Probiotics May Help Alleviate Autism Symptoms

00Autism, Diet, Featured news, Genetics, Mental Health, Trauma Psychotherapy August, 15

Source: David Robert Bliwas/Flickr

Probiotics can be found in many foods, like yogurt, soups, and even pizza, and are often viewed as a “cure-all” –from improving digestive health and immune function, to lowering cholesterol levels.

Probiotics are live organisms that, when taken in adequate amounts, have the ability to quickly colonize the gastrointestinal track and increase the amount of beneficial microbes, creating a balance in the gut microbiota that is considered health enhancing.

Autism Spectrum Disorder (ASD) is a neurobiological condition that impairs children’s social and communicative functioning, and often presents in the first three years of life.  Many children with autism experience severe gastrointestinal problems, and the associated discomfort often worsens behavior.

Currently, there is no cure for autism, nor have any drugs been developed to treat symptoms.  And no screening test can determine if a child is at risk for autism.  The disorder can sometimes be detected in 18 month olds, but the majority are not diagnosed until much older.

Recently, California Institute of Technology researcher, Elaine Hsiao found that treating mice who exhibit autistic symptoms with probiotics can restore both gut barrier function and behavioural abnormalities.

In Hsiao’s study, researchers injected pregnant mice with a virus that enhanced anxiety, decreased ultrasonic vocalizations, increased gut barrier permeability, and shifted the gut micro flora in the offspring.  When the offspring were given a human strain of Bacteroides fragilis as a probiotic, the bacterial balance was restored, and autism-like behavioural symptoms were alleviated.

A serum metabolite called 4-ethylphenylsulfate, produced by some mice gut bacteria, was found to be elevated in the offspring of the autism model.  After the probiotic injection, this metabolite decreased to normal levels.  Furthermore, injecting 4-ethylphenylsulfate into normal mice produced symptoms of anxiety, suggesting that this metabolite, in combination with others, affects neural circuits linked to autism.

Neurologist  Natasha Campbell-McBride, formerly at Bashkir Medical University in Russia, reported that almost all mothers of autistic children have irregular gut flora. This is noteworthy since at the time of birth, newborns inherit gut flora from mothers. An analysis of the gut micro floras of healthy and autistic children revealed that gut micro flora in autistic children is of lower quantity and diversity.

Studies have shown that infants born by C-section develop dissimilar and less diverse micro flora than naturally born babies.  It seems passage through the birth canal has a positive effect on the infant’s gut bacteria and may play a preventative role in autism.

The percentage of women having C-sections in the U.S. has increased from 5-10% in 1965 to 32.8% today.  According to the Centers of Disease Control and Prevention (CDC), autism rates are also on the rise.  Fifteen years ago, 1 in 10,000 children were diagnosed with autism.  Ten years ago, 1 in 1,000.  Current statistics from the CDC report the figure as 1 in 50.

Taken orally, probiotics have been deemed safe and are well tolerated for use during pregnancy. The most common adverse side effects reported are bloating and flatulence, which typically subside with continued use.  It is still unclear which strain of probiotic may be most beneficial.

To date, the Food and Drug Administration (FDA) has not approved any specific probiotic health claims and the quantity of probiotics needed to be beneficial is still unclear.

Celebrities like Jenny McCarthy believe that symptoms of autism can be relieved by dietary changes.  McCarthy claims a strict wheat and dairy-free diet cured her son.  But anecdotal reports are of limited value, often reflecting the idiosyncratic opinions of influential individuals.

Large-scale clinical trials that study the effects of diet on those with autism are needed. In the meantime, anecdotal evidence is compelling and may eventually lead to definitive findings.

Shifting micro flora in the gut may make a potentially useful treatment for autism available.  The method may even make assessing a genetic predisposition to autism possible.

Research is still in its early phases.  Probiotics may improve digestive health, but the jury is still out on whether they can definitively reduce autism symptoms.

– Jenna Ulrich, Contributing Writer, The Trauma and Mental Health Report

– Chief Editor: Robert T Muller, The Trauma and Mental Health Report

Copyright Robert T Muller

This article was originally published on Psychology Today


Forgetting PTSD: How Genes Affect Memory

00Fear, Featured news, Genetics, Memory, Neuroscience, Post-Traumatic Stress Disorder, Trauma, Trauma Psychotherapy April, 15

Source: Jared Rodriguez // Flickr

Memory can be a double edged sword. It holds our identities, our relationships, our histories. But when memory holds our most unspeakable stories, it can become a painful burden.

Sufferers of PTSD live with this reality. Many cannot forget. Recent studies have found that a gene, called tet1, plays a central role in forgetting such traumatic experiences.

Massachusetts Institute of Technology researcher, Andrii Rudenko, found that when people with normal levels of this gene experience a traumatic event, the triggers to traumatic responses become extinct over time. For example, if you were bitten by a dog after walking past a neighbour’s house, you may be reluctant to walk by that same house again. And if you continued to walk past the house and nothing happened, eventually the association with being bitten and walking past that house would become extinct –you would no longer fear walking past the house. However, people with PTSD do not form these new associations, and would continue to fear walking past the neighbour’s house.

Currently, one of the most effective treatments for PTSD is exposure therapy, where patients learn new associations by being exposed to the triggers of PTSD in safe environments. This can include practicing driving on a driving simulator for someone who is afraid to drive due to a motor vehicle accident. Over time, patients begin to learn that driving is not as dangerous as they came to believe.

The tet1 gene aids in the expression of genes in the brain that help people form new memories and cover up old ones. However, when a person has low levels of this gene, old and traumatic memories are not masked.

In Rudenko’s study, mice were conditioned to fear a particular cage using electric shocks. When the electric shock was taken away and the mice were placed in the cage, the mice with normal levels of the tet1 gene lost their fear of the cage, while the mice with low levels of the tet1 gene continued to fear as before.

A process called DNA methylation blocks the expression of the promoter genes that are responsible for forming new memories. The methylation process is lowered by tet1 and other tet proteins in areas of the brain that are important for forming memories, including the hippocampus and the cortex.

Simply put, the more tet proteins, the more expression of promoter genes and memories formed. Conversely, even though low levels of the tet1 gene make learning new things difficult, it has been hypothesized that fear responses are so strong that tet2 and tet3 proteins can compensate for the demethylation processes of tet1 proteins. Therefore, memories are formed during strong responses to fear or traumatic events, but with a lack of tet1 proteins, new memories are not formed to replace the old memories, and chronic PTSD is the result.

Li-Huei Tsai, director of MIT’s Picower Institute for Learning and Memory, told MIT news that “if there is a way to significantly boost the expression of these genes, then extinction learning is going to be much more active.” That is, if we can find a way to boost the expression of the tet1 gene, then people’s traumatic memories will be covered up by new memories quicker.

Memory extinction, prefrontal lobotomies, and other psychosurgeries have been a topic of popular film and literature. It’s not surprising that questions on how these findings may be applied to PTSD treatment have raised eyebrows.

According to Tsai, “What happens during memory extinction is not erasure of the original memory.” Instead, new memories and associations can be formed and old ones forgotten. In the case of the mice, the mice with the higher levels of the tet1 gene begin to learn that the cage is safe, and forget that it was once dangerous. In Rudneko’s view, “association with safety is rebuilt.”

Manipulating tet1 proteins in the brain and combining exposure therapy may bring new PTSD treatment possibilities. This method might even be used to assess a person’s genetic predisposition to PTSD. One imagines a possible screening tool for applicants to jobs with exposure to highly stressful events, like police officers.

This research is still in its infancy. Yet it shows promise for those who, despite their best efforts, can’t find a way to forget.

– Contributing Writer: Andrew McColl, The Trauma and Mental Health Report

– Chief Editor: Robert T. Muller, The Trauma and Mental Health Report

Copyright Robert T. Muller

Photo Credit:Jared Rodriguez // Flickr

This article was originally published on Psychology Today