Blaming Our Genes: The Heritability of Our Behaviors

This article helps to uncover the question of whether some traits people have are really beyond their control or something they could have picked up throughout their years of development.  When it comes to behavior, genetics plays a significant role, as shown by studies on various traits and disorders. Twin studies and family genetic studies help us understand the heritability of behaviors, indicating how much of a trait is influenced by genetics versus the environment, basically nurture vs. nature. Traits like intelligence and addictive behavior (food addiction, alcohol/drug addictions, sex addiction) both have substantial genetic components, with estimates of heritability ranging from 50% to over 90%, indicating that traits like these are more likely than not to get passed down across generations.  Disorders like schizophrenia, bipolar disorder, and depression also have strong genetic bases, with heritability estimates ranging from 70% to 85%. Similarly, conditions like familial advanced sleep phase syndrome (FASPS), obsessive-compulsive disorder, and autism have clear genetic components contributing to their development. Understanding the genetic basis of these behaviors and disorders can help destigmatize mental illness, improve diagnosis and treatment, and even lead to the development of new therapies.  This article was very interesting to me, but it also freaked me out in a way because of the way that disorders like depression and bipolar disorder can be passed down from generation to generation. I know someone who suffers from depression personally, so I know that the lows are very low and the high can be at times too high. I also know that this person really dislikes the fact that they have this disorder and would be incredibly upset at the fact that will more likely than not pass the trait down. I can't even begin to imagine how it might feel like it's all your fault when your child experiences similar struggles that you face.

Sources

1. https://thereader.mitpress.mit.edu/blaming-our-genes-the-heritability-of-behavior/

2. https://americanaddictioncenters.org/alcohol/hereditary-genetic

Consumption of alcohol on brain size

Consumption of alcohol on brain size

It was believed that heavy consumption of alcohol caused brain volume to decrease. Investigators from

Washington University (St. Louis, MO) and Duke University (Durham, NC), aren’t entirely ruling out this

thought, however, they have conducted studies that suggest that alcohol may not be the one to blame.

Their findings indicate that smaller brain volume and the predisposition to consume a fair amount of

alcohol are derived from an individual's genetic makeup. The study shows that individuals who consumed

more alcohol had “lower gray matter volume” in two regions of the brain, the dorsolateral prefrontal

cortex and the insula. Their analysis also showed that reduced brain volume in those two specific regions

were due to genetic composition. The investigators do still recognize that alcohol consumption does

reduce brain volume, however their findings suggest that “brain volumes started out lower to begin with.” 

https://www.medicalnewstoday.com/articles/326842.php#4

Related article: https://www.health.harvard.edu/blog/this-is-your-brain-on-alcohol-2017071412000

Alcohol can damage DNA and increase cancer risk

Scientist at the MRC Laboratory of Molecular Biology, Cambridge, gave diluted alcohol, ethanol, to mice. They then looked at the DNA sequencing and chromosome analysis to identify the genetic damage of acetaldehyde, which is a chemical produced when the body breaks down alcohol. Acetaldehyde was found to break down and damage DNA within blood stem cells leading to rearranged chromosomes and prominent alteration of DNA sequences. Damage of healthy stem cells leads to higher risk of developing cancers. It is important to understand that the body carries an enzyme, aldehyde dehydrogenase, that breaks down acetaldehyde into acetate but many people do not have this enzyme or carry a faulty form of it, particularly those from a South East Asian decent. When the effects of alcohol were monitored with mice lacking the ALDH enzyme were observed, it resulted in four times as much DNA damage in their cells compared to other mice. Obviously, there are also DNA repair mechanisms that can fix and repair DNA damage but these mechanisms and systems can sometimes be faulty. Thus, it will lead to more mutations in the body and eventually these can be harmful and cause cancers.

This was an interesting perspective to read about when it comes to binge drinking. I understood that binge drinking isn't good in general for your body but they did a great job explaining the effects it actually has. Essentially, binge drinking causes more mutations in the body that can eventually lead to cancers; specifically, it can lead to bowel and breast cancers. Perhaps, this could be why men are more susceptible to colon cancer because men binge drink much more than women do. I also find it interesting that there is so much contradicting research when it comes to alcohol; so much research has its beneficial effects of drinking and there is also tons that indicates how harmful it is for you.