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Posts tagged with genes


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New gene identified for depression

January 22, 2012 by .

A team led by Dr David Glahn (Glahn et al., 2012) claims to have identified a gene RNF123 which may play a role in major depression (as distinct from bipolar disorder/depression). This gene has been shown to affect the hippocampus, which in turn is implicated in depression. Smaller hippocampal volumes are often found in people with recurrent bouts of major depression. Smaller hippocampal volumes also appear to be associated with a lower probability of remission of depression with antidepressants.However, the causal nature of this relationship is not entirely clear. Hippocampal volume may be either a cause of depression or a consequence of it. For example, it might be the case that people born with a smaller hippocampus (because of the RNF123 gene) may be more vulnerable to depression (the diathesis-stress model). Alternatively, it could also be the case that the duration of untreated depression might in some way affect hippocampal volumes.

The picture above is apparently what RNF123 looks like!

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Something to Bragg about……

May 19, 2010 by .

Dreams, drugs, intelligence, memory, infant brains, psychoanalysis, human evolution and many more – Loads of online broadcasts from Melvyn Bragg’s ‘In Our Time’ Radio 4 series to be found here – all free – it makes one proud to be a licence payer….

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More ash news from Iceland

April 26, 2010 by .

A study from Decode Genetics in Reykjavik, published in Nature Genetics, suggests that four genes have now been identified – two linked to nicotine dependence and another two linked with nicotine metabolism. These findings, if valid, could lead to better understanding of addiction to smoking and how to treat this addiction.

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Why antidepressants don’t work

January 16, 2010 by .

Long-time depression researcher Eva Redei recently reported some of her latest findings. She has spent decades breeding rats who are severely depressed (mating depressed rats with depressed rats so you get ‘who are believed to be the most depressed rats in the world’ (!!)). This meant she could identify genes linked to depression. Next she exposed a different group of rats to stressful situations for two weeks which enabled her to identify the genes that consistently were associated with a poor response to stress.

The big news is that there was no overlap between the depression genes and the stress genes. This suggests that the idea that stress causes depression may be wrong. And, furthermore, she claims the reason antidepressants are often ineffective is because they treat stress and not depression and she has now shown that the two are not linked, though they may co-occur. So that’s one reason why antidepressants only work for some people (those suffering from stress and depression). Before you say ‘ah well, this is just an effect in rats’, Redei claims that rat brains are very similar to human brains, so it is reasonably to draw analogies. It also may explain why we like cheese. (No, that last bit was a joke).

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Genes, free will, responsibility, murder?

November 17, 2009 by .

If you  smash your fist into someone’s body are you being aggressive and anti-social, or are you just doing what your genes programme you to do? The idea of genes affecting behaviour isn’t new and isn’t disputed, but the use of certain genes as a mitigating factor in criminal behaviour is a contentious issue. Genes have been used as part of the defence in cases of murder, and moral and ethical arguments around this use have focused on the low validity of the research evidence plus the generally accepted concepts of free will and personal responsibility. The argument has been taken a stage further now as a convicted murderer in Italy has had his sentence reduced partly because of his history of psychiatric illness and also partly because his genome includes five genes known to be associated with violent behaviour. One of these genes is a variant of MAOA, which codes for an enzyme which breaks down amines in the brain, and this low-activity variant correlates in research findings with violence and aggression, giving it its nickname the “warrior” gene. However, as we all know, correlations are not necessarily causal; and then there is the responsibility debate. So, what would you decide if you were on the jury, the defendant was clearly guilty of murder, but also had a gene profile predisposing him or her to violence and aggression?

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Nature, nurture and schizophrenia

July 2, 2009 by .

DNA analysis of thousands of people in three separate studies has shown that the disorder is linked to the interaction of a large number of genetic variants on chromosome 6, in an area called the Major Histocompatability Complex which has one role in the immune system and another in controlling the switching on or off of other genes.

How many variants are there? Well, over 30,000 were identified as being much more common in schizophrenics than non-schizophrenics apart from people with bipolar disorder.

So not only is the genetics of schizophrenia far more complex than had been thought, environmental influences are also involved, but there could be a previously unexpected overlap between the two psychopathologies, schizophrenia and bipolar disorder (manic depression).

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Live long and prosper……

June 4, 2009 by .

spock.jpg “IT IS probably the most famous greeting in the universe.

But the simple Vulcan salute left makers of the new Star Trek film with a galactic-sized headache – because Mr Spock just couldn’t do it.

After much head-scratching, experts on the $150 million blockbuster – which boasts stunning high-tech effects – hit upon a low-tech but logical solution – gluing actor Zachary Quinto’s fingers together, The Mail on Sunday newspaper in the UK reports.

Quinto, 31, admitted he found it impossible to form his fingers into the distinctive V-shaped gesture, saying: “It’s much harder than it looks. Seriously.”

One on-set insider said: “Zach could do the salute some of the time but only after he’d positioned his fingers the right way off-camera.

“In some scenes he has to do the salute while speaking his lines so they ended up using skin-protective superglue, like they use in hospitals, to stick his fingers together.”

William Shatner, who played Captain Kirk in the long-running TV show and the first seven Star Trek films, was also unable to do the salute, so he used fishing line to tie his fingers together”. (Link)

So what’s going on there then? If the first Spock had Vulcan Hand Signal Ability (hereafter referred to a ‘VHSA’) why not the new guy?

Is it a genetic thing like tongue rolling? You’ve got the gene or you haven’t? Or is it a learnt thing like juggling or tying shoelaces? Once you’ve got the enactive ‘muscle memory’ in place you don’t have to think about VHSA anymore? Surely if it was a practice thing then the new Spock would beat himself up trying to master this skill…. I’m sure Christian Bale would put the effort in if he found himself in such a position.

My own limited research during lunch today indicates that it does get easier with practice, but you still have to think about the physical position of your fingers quite a lot. It also seems to help if you position your fingers whilst your arms are lowered and then raise them, but I’m not sure it looks as cool. So I don’t know… maybe I’ve just got the VHSA gene. But if I have, what possible evolutionary advantage could that have? I’m pretty certain that the ability to mimic characters from Star Trek is unlikely to enhance one’s reproductive potential……

(Couldn’t quite work out where this fitted in on the syllabus, but obviously had to get it in somewhere so, if you click on the ‘see rest of post’ link below, it’ll take you to the “VHSA Research Methods Worksheet”).

Read the rest of this entry »

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Monkey Business?

January 26, 2009 by .

Serotonin is involved in many behaviours, and new research suggests that a mutation in a gene that transports the brain chemical serotonin could influence our social behaviour.

This is based on American research using rhesus macaque monkeys because they are the only other primates with a particular genetic trait. Usually we are homozygous for this  emotion-regulating serotonin transporter gene, having either two long (L/L) or two short (S/S) versions. But previous research has shown that there are a few people - more common in those of Asian descent – who are heterozygous and have social anxiety and similar behaviours. Rhesus macaque monkeys are the only other primates with this genetic trait. The research showed that those with the S/L version spent less time looking directly at the faces and eyes of other monkeys, and were less likely to want to look at a picture of a high-status male monkey, and also were less likely to be risk takers, than those who were homozygous.

Platt says, “For both human and non-human primates, faces and eyes are a rich source of social information, and it’s well-established that both humans and macaques tend to direct visual attention to faces, especially the eye region. Rhesus monkeys live in highly despotic societies and convey social rank information by making threats and showing dominant and submissive behaviors.”

The findings could give researchers a new model to help in studying social anxiety, and perhaps more serious disorders such as autism and schizophrenia.

According to Watson, “Altogether, our data show that genetic variation in serotonin function does contribute to social reward and punishment in macaques, and thus shapes social behavior in both humans and rhesus macaques. This study confirms rhesus monkeys can serve as a model of what goes on in our brains, even in the case of social behavior.”

How similar are we to primates such as rhesus monkeys?

What are the arguments fordoing psychological research on animals such as these, and what are the arguments against this?

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Meet Val and Met, anxiety genes!

September 26, 2008 by .

Suppose you had an awful experience, something traumatic which shook you up and upset you deeply.  What would the effects of that be? How would you cope? Would you be able to deal with your memories, or would you have flashbacks, panic attacks, feel unable to get on with your life?

Researchers in Germany and the USA have been studying why some people develop PTSD (post-traumatic stress disorder) but others, in the same traumatic circumstances, don’t get the disorder and manage to cope with just bad memories.

The answer appears to be nature, not nurture, and is linked to one of the permissive amines, dopamine. Read the rest of this entry »