Hello there bloggies! Welcome to Science Sunday!
I am a human geneticist. In my research, I examine data generated directly from human subjects. It is easy to see the connection of our research findings with human health and disease. Sometimes, our findings can directly impact how health care is delivered and how people are treated.
However, the connection between research in other organisms and human health/disease can be far less clear. What does studying cancer in a mouse mean for patients suffering with cancer? What could studying neurodegeneration in worms have to do with those with Alzheimer’s disease? Research model organisms couldn’t possibly tell us anything that we wouldn’t learn from human research, right?
Wrong! Research in model organisms complements research in human subjects. Both have their advantages and nuances that allow researchers to untangle the mechanisms underlying biology and human disease.
So, what advantages do model organism research have over human-based research?
First, humans are incredibly difficult to control. I don’t think that point needs to be argued much! Human subjects love to misreport certain information, are prone to not adhering to study protocols, and sometimes drop out of studies. But even the best human subjects share one massive flaw. Each and every one of them comes from a different living situation and with their own experiences and routines. This diversity in environmental and treatment exposures can make any conclusions or findings incredibly difficult to detect. It makes determining causal effects even harder to prove.
Model organisms are largely free from this lack of experimental controls. The researcher can control what exposures and treatments are given to each model and when. This degree of control is just unreasonable to expect in a human study. But, here in a model system, the researcher can have more confidence in the causal relationships between variables and biological phenomena.
Second, an indication of human diversity is stored in our DNA. Each one of us (excluding identical twins) has differences in our genetic code. This diversity is what makes us all different, and life so interesting. But, this genetic diversity (which is usually an advantage and a positive) can add complications to human research. Differences in genetic code can have obvious influences on biological processes and add incredible noise to measurements.
One direct way to circumvent this issue of diverse genetic background is to control breeding. By choosing mating pairs, researchers can control what is different genetically among the samples. Now, consider the prospect of choosing and controlling the mates of other people (or just think about how parents try to guide their children’s mate choices…not a good situation). In model organisms, researchers can choose which organisms mate with which. Not only that, but these organisms are bred to be the same genetically other than what the researchers want to be different. It allows the researchers to be confident that inter-individual genetic differences are not responsible for the biological outcomes they observe. This cannot be achieved in humans.
Third, ethics and basic morals limit the treatments, exposures, and experiments in human samples. You can’t sample human brain tissue, directly edit the human germ line, clone humans, or expose humans to toxins. Some experiments just simply cannot be done in humans. In model organisms, these experiments are more suitable with reason. Brain tissue, genomic editing, higher dose drug exposure, and loads of other factors are accessible when you are using model organisms.
Human and model organism research are not mutually exclusive ventures. They work together to further the understanding of human biology and disease. Hypotheses generated in human studies can be examined specifically in model organisms and vice versa. Both types of studies should be used and funded in order to advance medical treatment and diagnosis.
Thank you for stopping by this edition of Science Sunday! Do you work in human or model systems? Or both? What organisms do you think are used as models? Let me know in the comments below or on twitter @DrFsThoughts.
Stay tuned for Tuesday’s post!