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The Genetics of the Immune System

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Last week, I had the opportunity to talk with a group of students from Grandview Heights School in Edmonton, Canada. The students are learning about genetics, and the instructor, John Chase asked me to talk about how genetics impacts my field, and to give them a perspective on how this stuff translates to the real world.

The quality isn’t perfect, and we had some technical glitches, but we recorded it using google hangouts, and you can see the full class here. Though not strictly food related, a lot of what I talked about will be relevant later when I talk about infectious diseases, allergies and autoimmunity. Skip ahead to 7:55 if you don’t want to hear all the autobiographical stuff and want to get straight into stuff about the immune system.

There were a lot of student questions that I didn’t get a chance to answer, like “Is there a difference between genetic modifications in humans and animals? What are possible improved characteristics if a human were to be genetically modified?” and “Are there known diseases that could have an effect like the black plague on the human race? Is it still possible for people to not be immune even though there has been lots of inter-breeding going on between cultures?”

I’ve posted answers to these questions (and more) over at my other blog. Please take a look if you’re interested.

Kevin Bonham About the Author: Kevin Bonham is a Curriculum Fellow in the Microbiology and Immunobiology department at Harvard Medical school. He received his PhD from Harvard, where he studied how the cells of the immune system detect the presence of infectious microbes. Find him on Google+, Reddit. Follow on Twitter @Kevbonham.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. mathari 2:45 am 10/16/2013

    10000 years ago, there were 1 million of us. 500 years ago 500 million of us. Today there are 7 billion. In other words, we are all almost identical (+99.9%). Our differences are like the colors on a peacock. They make up a very very small part of the equation.

    On the other hand, over the last 100 years, we have exponentially increased in rates of autism, schizophrenia, mental disorders, and cancer. These are complex disorders. There are some mendelian disorders capable of causing very specific outcomes but overall the variance in our genes cannot possibly cause such disorders or low IQ or cancer.

    The Genome Wide Association Study has compared the genes of normal people to the genes of people with schizophrenia, autism, etc. There are no differences. There is no functional mutation. There is striking similarity between us all. There may be some slight difference but it is slight – not enough to be responsible for anything more than what we refer to as within the margin of error. Certainly not enough to be responsible for the ills of society.

    Neurotoxins, on the other hand, cause these differences. For example – lead is a well studied one. People closest to the lead smelter in australia were studied (port perie). People closest had 15 point loss of IQ and schizophrenia and autism. People further 5 point loss and adhd. Clusters of areas such as homes with lead paint or next to a chemical plant that pollutes the environment see similar results. In these areas, you see heritability (claims of 70%) because everyone is affected. These areas have sharply increased the overall levels of complex disease from .1% to 10%.

    Genes could never cause, in 100 years, this much disparity. It is impossible and irrational.

    Link to this
  2. 2. rostopch 12:46 pm 10/16/2013

    Mathari, quit claiming a postulate as fact. How do you know there has not been an acceleration of genetic change in the past 100 years. I am not saying you are definitely wrong, but you saying that genes cannot be the cause is itself without evidence, and both irrational and arrogant.

    Link to this
  3. 3. Kevbonham 1:05 pm 10/17/2013

    @ Mathari – first of all, your comment is off-topic; just because we’re talking about genetics, doesn’t mean you should rail about your favorite gene-related topics.

    Second of all, your understanding of genetics is sophomoric – just because a trait does not follow mendelian inheritance, that does not mean there is no genetic component. There does not need to be a “functional mutation” or single gene control – these are complex disorders that likely have multiple causes, some genetic, some environmental.

    Third, you’re wrong about genome-wide association studies. Unless you thought there was a single definitive GWAS (your use of the definite article implies this), you must not have looked very hard. The top three results for “GWAS autism” in google scholar are:
    - Novel Autism Subtype-Dependent Genetic Variants Are Revealed by Quantitative Trait and Subphenotype Association Analyses of Published GWAS Data (
    - A noise-reduction GWAS analysis implicates altered regulation of neurite outgrowth and
    guidance in autism (
    - Transcriptomic analysis of autistic brain reveals convergent molecular pathology (

    Top hits for “GWAS schizophrenia”
    - Common polygenic variation contributes to risk of schizophrenia and bipolar disorder (
    - Common variants conferring risk of schizophrenia: A pathway analysis of GWAS data (
    - Analysis of 10 independent samples provides evidence for association between schizophrenia and a SNP flanking fibroblast growth factor receptor 2 (

    Link to this

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