How your genes interact with your environment changes your disease risk − new research counts the ways

Sitting in a doctor’s examination room, I was surprised when she told me, “Genetics really don’t care for chronic disease.” Instead, I continued, “A person’s lifestyle, what they eat, how much they exercise, and determine whether they suffer from heart disease.”

As a researcher He studies genetics from the diseaseI am not completely different – Lifestyle factors You play a big role in determining who suffers from illness and not. But it is far from the entire story. Since scholars Human genome identified In 2003, the researchers learned that heredity also plays a major role in the risk of a person’s illness.

Studies that focus on Appreciation of inheritance disease That is, the amount of genetic differences that explain the differences in the risk of the disease – usually a large part of the contrast of the disease to genetics. It seems that the entire genome mutations play a role in diseases such as Type 2 diabetesAnd it is about 17 % hereditaryAnd schizophreniaAnd it is about 80 % hereditary. Unlike diseases such as Tae Sax or CaseWhere mutations in one gene caused a disease, Chronic diseases tend to be multi -qualityThis means that it is affected by multiple mutations in many genes through the entire genome.

Each complex disease has genetic and environmental risk factors. Most researchers study these factors separately due to technical challenges and a lack of uniform databases. Although some have invented techniques to overcome these challenges, they have not yet been applied to a comprehensive set of diseases and environmental exposure.

In our recently published research, my colleague Alexon price Me Imported tools to take advantage of the newly available data collections to Determine the effects of the joint Its genetic and environmental risk factors on the biology behind the disease.

Aspirin, genetics and colon cancer

To clarify the effect of genes and the environment on the disease, let’s look at the example of the use of aspirin and colon cancer.

In 2001, researchers at the Fred Hetchenson Cancer Research Center were studying how Regularly The risk of colon cancer has decreased. They wondered whether the genetic mutations that slowed down the speed of the body collapsed – which means that the levels of aspirin in the body will remain high for a longer period – may increase the effect of a protective drug against colon cancer. They were right: Only patients with slow aspirin metabolism had a low risk of colon cancer, indicating that the effectiveness of the drug can depend on the genetics of a person.

This raises the issue of how genetics science and different Groups of environmental exposureLike medications that the patient takes, it can affect the risk of a person’s illness and the effectiveness of treatment for them. How many cases of genetic differences that directly affect the effectiveness of the drug?

The interaction between genes and the environment for colon and aspirin cancer is unusual. It involves a mutation in one location in the genome that has a significant effect on the risk of colon cancer. The past 25 years of human genetics showed that these types are from Large influence mutations are rare.

For example, an analysis found that the medieval effect of the genetic alternative is on the height Only 0.14 mm. Instead, there are usually hundreds of differences that each have small but cumulative effects on the risk of a person’s illness, which makes it difficult to find.

How can researchers discover these small genetic reactions and the environment across hundreds of sites in the genome?

Interactions of genetic genetic genetics

We started searching for cases in which genetic variables across the genome showed different effects on a person’s biology in different environments. Instead of trying to discover the small effects of each genetic variable at the same time, we Collected data across the entire genome To convert these small individual effects into a significant effect on the genome scale.

Using data from UK BIOBANK – A large database that contains genetic and healthy data from about 500,000 people – We estimated the impact of millions of genetic variables on 33 complex features and diseases, such as height and asthma. We assembled people based on environmental exposure such as air pollution, cigarette smoking and food patterns. Finally, we have developed statistical tests to study how genetics effects on the risk of diseases Biomasia levels It differs with this exposure.

We found three types of genetic reactions and the environment.

First, we found 19 pairs One of the complex features and environmental exposure is affected by genetic variables across the genome. For example, the effect of genetics varies on the levels of white blood cells in the body between smokers and employees. When we compare the effects of genetic mutations between the two groups, the strength of the interaction between genes and the environment indicates that smoking changes the way inheritance affects the number of white blood cells.

Second, we searched for cases where the inheritance of the characteristic differs according to the environment. In other words, instead of some genetic variables have different effects in different environments, all of which have become stronger in some environments. For example, we found that inheritance of the BMI – the weight ratio to the height – increased by 5 % for the most active people. This means that genetics plays a greater role in the body mass index as you are more active. We found 28 These husbands of features and environmentIncluding HDL cholesterol levels, alcohol consumption, as well as nervousness and lack of self -reporting.

Third, we searched for a kind of interaction between genes and the name called Passive or joint amplification. Here, genetic effects grow with increased environmental exposure, and vice versa. This leads to a relatively equal balance of genetic and environmental effects on a feature. For example, as the time to be self -reported in watching the TV, the genetic and environmental contrast increased the waist to the hip of the person. This probably reflects the effect of other behaviors of time to watch TV, such as low physical exercise. We found 15 of these husbands of features and environmentIncluding the ability of the lung and smoking, glucose levels and alcohol consumption.

We also searched for cases in which biological sex affected, rather than environmental exposure, on interactions with genes. The previous work has shown evidence of these Jin thanks to sex InteractionsWe found additional examples of the effects of biological sex on all kinds of reactions between genes and the environment. For example, we found that nervousness had genetic effects varying through sex.

Finally, we also found that multiple types of genes and the environment can affect the same feature. For example, the effects of genetics varied on systolic blood pressure by sex, indicating that some genetic variables have different effects in men and women.

New models for the environment genes

How do we understand these distinct types of genetic environmental reactions? We affirm that they can better help researchers understand the basic biological mechanisms that lead to the genetic and environmental risks of the disease, and how genetic variation leads to differences in the risk of disease between people.

Genes related to the same function work together in a Unit called the path. For example, we can say that genes participating in hem making – the component of red blood cells that carry oxygen – a collective part of Him synthesis path. The quantities of hemes circulated in the body affect other biological processes, including those that can lead to development Anemia and cancer. Our model indicates that environmental exposure modifies different parts of these paths, which may explain the reason we saw different types of genetic environment reactions.

In the future, these results can lead to more specialized treatments based on a person’s genome. For example, one day doctors may be able to know if someone is more likely to reduce the risk of heart disease by taking weight loss or exercising.

Our results show how to study interactions between the genetic environment only tell researchers about the genetic and environmental factors that increase the risk of disease, but also what is the error in the body where.

This article has been republished from ConversationAn independent, non -profit news organization brings you facts and trusted analysis to help you understand our complex world. Written by: Aaron Duvasolaand South California University

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Arun Durvasula has received funding from the National Institutes of Health and the National Institute of Science.