Understanding The Genetics Behind Addiction Blog #4

 

Angelina Tadros

November 25, 2025

Dr. Barbato

Genetics Blog #4

Understanding The Genetics Behind Addiction

A recent NIH study talks about a study done, funded by Washington University, that discovers genetic markers commonly inherited across multiple different substance use disorders (SUDs) by analyzing genomic data from over 1 million people. The researchers connected single nucleotide polymorphisms (SNPs) associated with general addiction risk, as well as substance specific risk for alcohol, cannabis, nicotine, and opioids. The study emphasizes the role of dopamine regulation in addiction, reflecting that variations in genes controlling dopamine signalling, rather than dopamine itself, are central to risk. These discoveries give good insight into commonalities across SUDs and reinforce the potential for personalized prevention and treatment strategies.

Addiction not only has a genetic factor but also significantly impacts brain function, specifically in areas such as the prefrontal cortex, which is responsible for judgement and impulse control. This explains why many people struggle trying to break their addiction. Functional Imaging studies like, fMRI and PET scans, show that the brains of people with SUDs show altered activity in the reward system, specifically in the nucleus accumbens part where dopamine releases signals pleasure. Abuse of drugs floods this system with dopamine, creating a higher and higher tolerance over time and increasing cravings to get the original high (that won't ever be reached again), even as natural rewards are less pleasurable. Imaging data from a similar source also reveals while substance use alters brain function, recovery is possible. Abstinence and interventions like physical exercise can help restore neural activity and improve executive functioning. Figure 1 below shows proof of the restoration of brain function as a result of continued abstinence.

Figure 1

Studying both genetics and brain imaging shows how some people inherit genetic variations in the genes that control dopamine signaling, which can affect how the brain's reward system responds and increase their risk of developing some sort of an addiction. Knowing a person’s genetic risk and how substance use affects the brain can help personalized prevention measures and treatments. This study confirms although substance abuse damages/alters the brain, it is possible to recover. This hopefully gives hope to those who struggle that they are not too far gone. I learned it is important to know your genetic risks in order to give yourself a head start on prevention and personalized care, genetics affect risk but don’t predict a person's future if you are in the know.

Sources

article:https://www.nimh.nih.gov/news/science-updates/2023/new-nih-study-reveals-shared-genetic-markers-underlying-substance-use-disorders

Picture+other source: https://www.recoveryanswers.org/recovery-101/brain-in-recovery/

Are we born political?

 Dr Leor Zmigrod has made a discovery, the politics a person associated with is correlated to biological factors. She has found that the brain structures of a person differ based on the types of politics a person follows and if their thinking is "flexible" or "rigid". For example, people with conservative beliefs have a larger amygdala, when compared to people with liberal ideologies. The amygdala being the part of the brain that processes fear and disgust. 

On a genetic level, it was found that people who are more cognitively flexible, have genetic markers that indicate greater amounts of dopamine in their prefrontal cortex, and less in the striatal regions of the brain. Dopamine has been known to be a genetic factor in personality, like extraversion traits. 

This can be a scary concept, as biological determinations for politics take away from hope that people can adapt their beliefs, as well as fear of interfering with a person's genetics/brain composition in order to change beliefs. These findings also emphasize how some individuals are more susceptible to political influences like propaganda. 

Dr Zmigrod mentions that she plans to do a longitudinal study, to determine if the brain's structure influences politics, or if politics influences the makeup of the brain later in life. 

Article

More on Dopamine and Personality

Fruit Fly Brains

Ana Marija Jakšić Shapes Fruit Fly Brains

     Ana Marija Jakšić investigated the evolutionary differences in drosophila, when exposed to high or low temperatures. The most heavily impacted portion of the drosophila were their brains and the neural genes, expressed in one temperature versus another. The strongest and most consistent response was that of the dopamine-producing neurons, which dampens the expression of several neural signaling based genes. This caused the drosophila to develop higher levels of spontaneous locomotor activity (measured by how fast they scaled the walls of a vial, when startled). Jakšić began to investigate whether different genotypes are better able to “ameliorate” the locomotor changes, by artificially altering the levels of the drosophila’s dopamine. She hopes to apply this data to human conditions where dopamine imbalances cause uncontrollable movements, like Parkinson's disease. This particular article delves into the research done by Jakšić, in a general summary, while also linking her papers. This research could help develop better treatments for Parkinson’s and other similar diseases.

Link to the article:

https://www.the-scientist.com/scientist-to-watch/ana-marija-jak-i-shapes-fruit-fly-brains-69863

Other associated links:

https://elifesciences.org/articles/53237

https://academic.oup.com/mbe/article-abstract/37/9/2630/5836827?redirectedFrom=fulltext&login=false

The Epigenetics of Addiction and Depression

     

    Dopamine controlling genes may be a root cause of addiction to drugs like alcohol and cocaine, as well as an answer to why drugs for depression need to be taken for weeks before they have an effect, according to the article The Epigenetic Secrets Behind Dopamine, Drug Addiction and Depression, by R. Douglas Fields.

    Neurotransmitters may have more to do with this process than we realized. Neurotransmitters transmit signals between neurons, which allows us to think, learn, and feel. When neurotransmitter signals misfire, we suffer problems with thinking, making decisions, or mood disorders, like depression or bipolar disorder. Serotonin, a kind of neurotransmitter known as a monoamine, helps to regulate moods and to treat depression, drugs that increase the level of serotonin in the brain are usually prescribed. According to research led by Ian Maze done last year, serotonin has another function: it can be used as one of the special markers of DNA. Specifically, serotonin bonds to a histone, the protein used as a spool, known as H3. H3 controls the genes that turn human stem cells into serotonin neurons. Maze’s team figured that if serotonin had this function, there was a chance that dopamine could also do the same thing, with the genes that control drug addiction. After all, the same enzyme that bonds serotonin to H3 also allows dopamine to be attached to H3, in a process called dopaminylation. This discovery may be essential for future research into addiction, or even broader, other kinds of mental illness, and how to treat these disorders. I already knew that genetics affected disorders and diseases like these, but it is also very interesting to look at how epigenetics plays a role.

Additional Links

https://www.psychologytoday.com/us/blog/integrative-mental-health-care/201912/epigenetic-influences-addiction

Do Parkinson's Disease and Genetics Have a Connection?

    One of the most infamous diseases out in the world today is the nervous system destroyer, Parkinson's Disease. To give an exact definition of this disease, it can be described as a brain disorder that leads to shaking, stiffness, and making walking and talking very hard. Usually, Parkinson's Disease occurs when one gets older in age. How it works is that, the cells that produce dopamine, get mutated and lose function. This is why people who have this disease have very hard times walking, moving around, and talking. Pictured above is Pittsburgh Pirate and Cincinnati Red legend, Dave Parker. He was a tremendous player who helped the Pirates win a world series back in the 1970's and was on the world series winning Reds in 1989. He currently has Parkinson's Disease and in current videos of him, it is obvious that he has the disease by seeing his shakes and his very limited movements to his body.

    Like a lot of diseases, it is very important to understand the genetics behind it. Some questions may be if it random that one gets this disease, or if a family history of it will land a bigger chance of one getting it. According to some studies done, about 10-15% of Parkinson's Disease have to do with a genetic factor, while the other 85-90% have to do with randomness and environmental factors. One interesting fact that is still an unknown is that groups like the Ashkenazi Jews and North African Arab Berbers have a much higher case of genetic transfer of this disease. Furthermore, if someone is genetically tested, and they are found to have a gene that is associated with Parkinson's Disease, they are still at an extremely low risk of actually getting the disease. So, Parkinson's Disease mostly develops by environmental factors and by randomness. Having family history and genes that are associated with PD only raise the chance of the person getting it by a very low percentage.

Parkinson.org/understanding-parkinsons/cause/genetics

https://www.nia.nih.gov/health/parkinsons-disease#:~:text=Parkinson's%20disease%20is%20a%20brain,have%20difficulty%20walking%20and%20talking.

Can ADHD be Inherited?

Attention deficit hyperactivity disorder, commonly known as ADHD, can effect a person’s attention, behavior and learning ability. The disorder seems to impair neurotransmitters in four different regions of the brain. 

In reference to ADDitude, Inside the ADHD Mind,  researchers suspect a gene is involved in the creation of dopamine, or lack thereof, which may be traced to the effects of ADHD. Dopamine functions as a neurotransmitter in the brain that can affect a person’s mood, learning and concentration. Although experts can not be sure exactly what causes ADHD, those with a parent or sibling with the condition are at greater risk. 

Can a Brain Scan Help Diagnose ADHD? -American Health Imaging

Researchers believe a combination of genetic, environmental and social factors contribute to the latency of ADHD. To continue the research, scientists evaluated DNA in search of variations contributing to ADHD. Researchers studying ADHD believe more than on gene is associated with the disorder due to its complexity. In 2018, a global team of researchers completed a study where they discovered genetic variations that accounted for about 22% of the risk for ADHD. For further information, the study can be read at Nature’s Genetics.

According to the Journal of Clinical Child and Adolescent Psychology, a study from 2016 reports 9.4% of children between the ages of 2 and 17 years of age, received an ADHD diagnosis. That equals approximately 6.1 million children in the United States. I knew ADHD was common, but the numbers from this study were shocking to me. With a disorder being so substantially common, it’s hard to believe scientists, researchers or doctors still don’t know what causes it. Oddly enough, this article ties into our lecture today because if researchers believe more than one gene is linked to the affects of ADHD, it would make sense for genes to be linked or how crossing-over plays a role in the diagnosis of ADHD. 

The Genes Behind Thrill-Seekers

A connection between genetics and daredevil activities was always predicted, but never proved until a study done by Canadian scientist Cynthia Thomson. This scientist brought together two sample sizes of people: one sample size being about 100, and the second being about 400. The second sample was a replication of the first one. In each sample, the test subjects were given two questionnaires to fill out, and their DNA was swabbed. One questionnaire tested for daredevil tendencies, and the other questionnaire tested for standard personality traits. A high combined scored on the questionnaires would indicate more risky character. It was found in the highest-scoring individuals that many had a variant in the DRD4 gene, which is believed to be connected to the dopamine receptors in the brain and affects risky behavior. It was therefore found that individuals with a variant in the DRD4 gene have a tendency to seek more thrill than others, because they need more stimuli in order to reach their optimal level of excitement.



It seems that a lot of things can be explained by genes. The fact that some people are thrill-seekers, and the fact that others aren’t--this can be explained by the DRD4 gene. It makes me wonder if a penchant for spicy food or horror movies can be explained by genes as well. I find it amazing how so many parts of our lives can be explained by genes. What would have previously been thought of as a personality trait is actually something passed down through generations. To be honest, it scares me to think that so many of the things humans do are explained by genes. People would want to think that they are the way they are because they are uniquely themselves, and that they are mostly responsible for the person they are. While things such as overall personality, beliefs, and speech patterns are solely the creation of each individual, it is daunting to believe that many aspects of one’s life are out of one’s control.

A Cure for Parkinson's?


The article "A Cure for Parkinson's? Replacing Damaged Brain Cells Shows Promise" discusses how researchers found that by converting glial cells into dopamine producing cells, decreased the symptoms of Parkinson's disease. In the brains of patients with Parkinson's disease the dopamine producing cells become destroyed or damaged which leads to the motor control symptoms like tremors and balance issues. Researchers have been trying to find a way to replace or repair these dopamine cells. So, Professor Arenas and his colleagues from the Karolinska Instituet in Sweden, focused on transforming cells into dopamine producing cells. They converted glial cells, astrocytes, into dopamine producing cells. Then placed these cells into mice with Parkinson's and the mice showed less symptoms of the disease. This research allows them to possibly find a cure for a disease that many people have been waiting for,

http://www.medicalnewstoday.com/articles/316896.php

http://www.mayoclinic.org/diseases-conditions/parkinsons-disease/basics/definition/con-20028488

A positive outlook for Parkinson's Disease

Researchers have been working on ways cure Parkinson's for years. Recently, a study was published that researchers have transformed non-neuronal brain cells into brain cells that can create and produce dopamine.  Dopamine is important for movement and coordination of the body, and in Parkinson's, dopamine cells become damage and even destroyed. The process f converting the cells is called cell reprograming,  changing glial cells into the dopamine cells.  Within the cell reprogramming, the researchers combined genes, four to be exact, that help create the dopamine cells with the transcription factors. The results have have been remarkably great, and show great hope for the future. As a person that knows someone with Parkinson's disease, I think this article does give great hope to reader that know about Parkinson's. Their testing seemed realistic and had great outcomes, so I hope more research is done and a cure can be found sooner than later!

Article

More info on Parkinson's Disease

Dopamine Levels with Music are Actually Influenced by Genetics

Source ArticleBrain on Music
Music can have varying effects on a person's feelings or on how they behave based off the possibility that music has an influence on one's levels of dopamine. In a new study conducted by Professor Elvira Brattico in two Italian hospitals with the help of the University of Helsinki, researchers were able to identify that variations within the genetic sequence which codes for dopamine receptors are what determines how one will react to music and sounds. They determined that based off of a GT and GG phenotype that there will be different reactions from each person.
GT subjects reacted to music with a mood improvement, and GG subjects reacted to sound with mood deterioration. Information such as this can greatly help with people who have abnormalities within their dopamine levels and with more research into the topic can perhaps provide types of therapies can be created.
The experiment description within the article is not very specific, and it is possible that it may have an effect on the results. The article simply describes the music as music and sound as sound, and claimed that sound was bad for dopamine levels on GG subjects and music was good for GT subjects. What was the effect of music on GT subjects and the effect of sound on GG subjects? What types of sounds were being played because naturally if a researcher blasts loud nails on a chalk board sounds into one's ears they will most likely react negatively and their mood will decline.

Replacing damaged brain cells reveals a possible cure for Parkinson's Disease



Parkinson's disease (PD) is a chronic disorder that gets increasingly worse over time. It involves the malfunction and death of vital nerve cells located in the brain. Patients with PD suffer with symptoms like tremors (of the hands, arms, legs, jaw, and face), impaired posture and coordination, bradykinesia (slowness of movement), and more. In recent months, researchers have discovered a way to transform glial cells of the brain into dopamine-producing brain cells. The dopamine these cells produce is a neurotransmitter that sends signals to the substania nigra, a part of the brain that is associated with movement and coordination as well as other areas of the brain. The dopamine-producing cells in the brain of an individual diagnosed with Parkinson's are damaged which leads to a lack of dopamine in parts of the brain and cause tremors, impaired balance and coordination, and slow movement. Neurons from fetal mid brain tissues were the first form of transplant experimented with, however, due to the difficulties of obtaining these neurons, stem cells or reprogrammed cells are often used.

Professor Ernest Arenas and his colleagues of the Karolinska Institute of Sweden have furthered the research of transplanting and study the process of reprogramming cells, which avoids transplanting cells in the brain by converting existing cells into other cells, like dopamine-producing cells. The researchers combined certain genes that shape dopamine cells with transcription factors. The research conducted by these scientists and the works published is Nature Biotechnology has proven to be a significant step forward in the process of curing the millions of people who suffer from Parkinson's worldwide. If further studies take place, even more genes that promote the generation of dopamine cells and will give an even larger possibility of terminating Parkinson's disease.

Another Excuse to Skip the Gym Today?

Are you one of those people who will find any excuse to avoid getting in a workout?  Well, this behavior might actually be in your genes.  According to researchers, anywhere from 20% to 60% of physical activity tendencies can be passed down to the next generation.  They found that the genes that control dopamine levels may effect a person's attitude toward exercise, whether they love it or hate it.  Dopamine is a neurotransmitter that effects a person's drive, pleasure, and reward centers of the brain.  So in conjunction with other behavioral traits and social influences there can be an indirect effect on levels of physical activity.

As someone who absolutely loves exercise it made me wonder if there were any genetic links to why that is.  After reading about the study it makes a lot of sense that it would be related to neurotransmitters that effect mood and motivation.  I've grown to love it so much because it's an escape, or an outlet, to clear things from my mind that are bothering me and to release negative feelings..

Can We Find the Genes Causing Depression ?

Even with modern genome analysis techniques, it is difficult to identify genetic factors affecting risk for depression. Since we know that depression is hereditary, it is reasonable to deduce that eventually we will be able to identify its genetic loci. To figure this out we need to look at larger sample studies which is challenging.

The authors of the study which have come up with this hypothesis are currently working on finding this loci. This research is import because depression is one of the most common, disabling and costly mental health conditions. By understanding its causes, such as genetics and environmental factors, it will help us focus on the interactions of these implications for prevention and treatment. Depression runs in families and based on studies of twins, it is estimated that genetic factors account for 40% of the risk. Genes are suggested to affect depression by influencing dopamine and serotonin neurotransmission.

 

A study from 2003 suggests that an interaction between a gene variant affecting serotonin and stressful life events can cause depression. However, studies have had conflicting results when examining gene by environment (GxE) effects. This is why researches are looking to do a large scale GxE study in hopes it will lead to further discoveries. The goal of this research is to more closely identify the particular genes that are possibly a cause of depression to better help prevent the disease and improve the lives of those who suffer from the disease. 

Article Used: http://www.sciencedaily.com/releases/2015/01/150107122305.htm

Related Article: http://www.nature.com/mp/journal/v14/n12/full/mp200848a.html

Some people 'hardwired' to prefer high-calorie foods, study finds

When trying to stay healthy, some have troubles saying no to a chocolate bar and getting a salad instead. More than a third of adults in the US, approximately 78.6 million people, are obese, which means that they are at increased risk of heart disease, stroke, type 2 diabetes and some forms of cancer. New studies have shown that this may be caused because the brain is "hardwired" to crave foods high in fat and sugar. Study leader Dr. Tony Goldstone has identified that two genetic variants that influence whether we opt for high-calorie or low-calorie foods. A team of scientists conducted a study of DNA genotyping on 45 European adults to identify the presence of variants near the two genes, FTO gene and the DRD2 gene. The FTO gene is associated with obesity predisposition and the DRD2 gene plays a role in the regulation of dopamine in the brain. After the study was conducted, researchers found that participants who had a variant near the FTO gene and rated the high-calorie foods were more appealing and demonstrated greater activity in the part of the brain called the orbitofrontal cortex.

Based on their findings, the researchers suggest that individuals who possess the FTO gene may be at greater risk for obesity early because dopamine signals trigger a sense of craving and reward in the presence of unhealthy foods. There was one possible treatment that was suggested to work would involve hormones that target dopamine cells in the brain to alter the hormone's influence on cravings for high-calorie foods. I believe that the people that possess the FTO gene may have a higher risk of obesity because of the dopamine signals that are triggering craving senses, but this may not be valid for everyone because everyone's body has different ways of working. A good way to avoid these cravings and not using a hormones as a treatment would be self control and not having high-calorie foods in your household or going into stores and restaurants that have these foods to avoid temptation.

Link to article:

http://www.medicalnewstoday.com/articles/301852.php

Link to alternative article:

http://www.sciencedaily.com/releases/2015/11/151105103957.htm

Are obese tendencies controled by gene variants?

A study presented during Obesity Week by researchers at the Imperial College London suggest they have found a pair of genetic variants that seem to correlate with obesity, as a result of increased reward responses in the brain to foods high in sugar and fat.  These two variants are located in the FTO gene and the DRD2 gene which are associated with risk of obesity.

The study found that activity in the striatum is increased in individuals with the FTO variant when looking at high calorie foods, this is only seen in those with a certain DRD2 variant, meaning that DRD2 variants have an effect on the dopamine system.

As a result of their findings the researchers suggest that individuals with FTO variants as well as DRD2 variants are more likely to be obese as a consequence to their altered dopamine signals, which cause them to have increased cravings for high calorie foods.

I find this to be quite interesting, because these results can possibly give some explanations as to why there are individuals who just struggle with being overweight, where the usual weight lose interventions don't exactly help.  Now that we know there could be some type of gene variation behind these behaviors, better more efficient "treatment" plans can be put into place, and maybe even some medications can be made/discovered to help these people who struggle with being overweight and constantly craving foods that are not good for them and causing their weight gain.

Original article

Study Finds Some People are 'Hard-Wired' to Prefer High Calorie Foods

Study leader Dr. Tony Goldstone, from Imperial College London in the UK, and colleagues have identified two genetic variants that influence whether we opt for high-calorie or low-calorie foods - a finding that that could open the door to more personalized treatment options for obesity. Dr. Goldstone and his colleagues set out to determine whether a person's food choices may be influenced by certain genetic variants. They conducted DNA genotyping on 45 European adults aged 19-55 to identify the presence of variants near two genes: the FTO gene, which has been associated with obesity predisposition, and the DRD2 gene, which plays a role in the regulation of dopamine in the brain. The subjects had a body mass index (BMI) ranging from 19 kg to 53.1 kg. Those subjects were asked to view pictures high and low-calorie foods and rate how appealing they were, while the researchers used functional magnetic resonance imaging (fMRI) to view brain activity.

They found that the participants who possessed a variant near the FTO gene and who rated the high calorie foods as more appealing demonstrated greater activity in a part of the brain called the orbitofrontal cortex. Based on their findings, the researchers suggest that individuals who possess the FTO gene may be at greater risk for obesity because dopamine signals trigger a sense of craving and reward in the presence of unhealthy foods. Dr. Goldstone says "It means they may experience more cravings than the average person when presented with high-calorie foods leading them to eat more of these foods." The study team suggests using gut hormones that target dopamine cells in the brain to alter the hormone's influence on cravings for high-calorie foods.

Obesity, basically, means having to much body fat and is different from overweight, which means weighing too much. Obesity occurs when over time when you eat more calories than you use. From this study, the team suggests that people who have the FTO gene may have a risk for obesity because of the dopamine triggers a sense of craving. This is very interesting because I had no idea obesity could be traced to the genetic level. This finding could be very beneficial to more treatments in the future, and may help stop obesity. More than a third of adults in the US, 78.6 million people, are obese and this study could help bring that number down because obesity can lead to heart disease, type 2 diabetes, and many more harmful diseases. This study helped me open my eyes about what foods to eat.

Original article here 

Some People 'Hardwired' to Prefer High-Calorie Foods, Study Finds

A new genetic study from a team of researchers at Imperial College London in the United Kingdom has identified two genetic variants, which exist near the FTO and DRD2 genes, as potential influences on whether a person prefers high-calorie or low-calorie foods.  The FTO gene has been proven to be associated with obesity and the DRD2 gene plays a role in dopamine regulation in the brain, which affects our sense of reward and craving in our bodies. With obesity being such a huge problem in the United States, as more than a third of the adults in the U.S. being obese, Dr. Tony Goldstone and his colleagues set out to determine whether these genetic variants could be the reason why so many people find it hard to stick to a healthy diet.

The team performed DNA genotyping on 45 white European adults, with ages ranging from 19 to 55 and of body mass index's ranging from 19.1 to 53.1 kg/m^2, to determine the presence of variants near the FTO and DRD2 genes. The subjects were then asked to view pictures of high-calorie and low-calorie foods and rate how appealing they found the food, while researchers used functional magnetic resonance imaging to analyze their brain activity.

From the study, researchers found that participants who possessed a variant near the FTO gene and who rated the high-calorie food as the most appealing showed greater activity in the orbitofrontal cortex and striatum of the brain. These findings suggest that individuals with the FTO gene variant have a great risk of obesity as it influences dopamine signals to trigger a sense of reward and craving when in the presence of unhealthy, high-calorie, food. This causes the person with the gene to experience more cravings than the average person when in the presence of food that is high in fat and/or sugar.  

From the results of the experiment, the team of researchers believe those who have the FTO and DRD2 gene variants may need more personalized treatments for obesity, such as using gut hormones to target dopamine cells in the brain and alter the hormone's effect on the craving for high-calorie foods.  

I, personally, find this article fascinating. It's interesting to believe that something such as our desire to eat unhealthy foods can be influenced by our genes and genetic variants. It really speaks to how much our genes influence us, not only in appearance, but in behavior. The study definitely allows us to better understand the biology and genetics behind our behaviors, especially the ones that predispose some of us to crave and overeat high-calorie foods. I think it also goes a long way in helping to potentially solve the obesity problem in the U.S.

For a link to the original article click here
For more information on the FTO and DRD2 genes and their effect on obesity click here

Placebo Effect

New research suggests that the strength of the Placebo effect could be affected by one's genes.

Scientists have been researching how one's genes can affect how a  positive effect a placebo will have. Studies suggest that better knowledge of this area could make for more effective treatments.The effectiveness lies in genetic signatures and the likelihood to have a beneficial response. Studies have found that when presented positively, the placebo has a beneficial response, even when people know that the drug is a placebo. Even when the drug is real, the effect is more positive when the patient knows their taken it. ___

The key area of research seems to be important is the production of dopamine, a neurotransmitter that is involved in both pleasure and movement. The way that each person's brain interacts with neurotransmitters determines how they perceive sensations and symptoms. There are many variations within the genes that could play a factor in the effectiveness of the placebo effect.

The ethical questions lies in whether mapping this area of research would make drug research more effective. Is it ethical to give a patient with a stronger placebo effect a lesser dose compared with someone who does not? Could placebos boost the effectiveness of drugs? These questions are all being researched more and are being integrated into modern medicine.

Link: http://www.philly.com/philly/health/topics/HealthDay698336_20150413_Genes_May_Make__Placebo_Effect__Stronger_for_Some__Study_Says.html

The genetics that cause hens to peck

Marjolein Kops from Utrecht University hypothesizes that two chemicals, serotonin and dopamine, along with management and genetics affect the desire of hens to feather peck. Serotonin helps regulate mood, impulsiveness and aggression and dopamine is involved in motivational and reward-related behavior. Severe feather pecking in a flock can be trigger by stressors, such as diet, environmental disturbances or housing conditions and can be measured by the lack of feather cover of victims. Due to the small of DNA variations of hens, some are more vulnerable to the triggers setting off dopamine/serotonin receptors, which cause onsets of severe feather pecking during adulthood. Dr. Kops.

During the study, Dr.Kops used leghorn birds, one group being aggressive and the other being more docile, and examined the birds’ brain distribution of serotonin and dopamine. Through the study, she categorized the birds based on pecking behavior; first order peckers and second order peckers.. First order peckers instigated pecking, which influenced others, second order pecker, to peck. Another categorized group were the victim and the non-pecker. The first order pecker birds were genetically inclined to peck by stressors. Whereas, the second order will only peck after witnessing the damaged feathers of victims. Dr.Kops states that further research is needed to assess the categorization of the birds and brain chemicals produced by the birds.

Dr. Kops research can help farmers identify and remove aggressive birds in young flocks to reduce pecking. Also, it can reduce injuries or deaths cause by pecking and reduce the need to trim beaks of birds to stop/prevent pecking.

Original Link: http://www.fwi.co.uk/poultry/the-genetics-that-cause-hens-to-peck.htm
Related Link: http://en.wikipedia.org/wiki/Feather_pecking