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Interview with Dr. Isabelle Nadeau

November 19, 2018

I am a Ph.D. scientist and a DNA testing expert. I am also the owner of a performance nutrition coaching business, something that actually applies quite a bit to consumer DNA testing these days. I worked as a scientist in the field of biochemical engineering for 15 years studying the metabolism of human cells.

I mainly studied cells in controlled environment to understand how to harness their powers to produce the molecules that we wanted them to produce. Utilizing genetic tools, such as qPCR, helped me characterize and optimize cell culture conditions furthermore. Understanding how to effectively feed cells ultimately led me to want to work with athletes to better comprehend their nutritional needs. Now I often use genetic testing to make more informed decision on nutritional recommendations.

Q: Can you tell us a little bit about your education, your background, and your expertise in genealogy and DNA/genetic testing?

A: I have an undergraduate degree in Chemical Engineering and then I specialized further in Biochemical Engineering, completing a PhD in the field of cell culture and metabolism. More precisely, I studied the metabolism of cells in controlled environment and tried to optimize the culture conditions so they could produce what we were looking for, either a protein or a virus of interest.

To make sure that my cell cultures were clonal, meaning that they originated all from the same cell with identical genetic material, or to select cells that were genetically predisposed to produce what we wanted them to produce, I used some genetic techniques such as qPCR, q standing for quantitative. In a nutshell, we would design a probe, which is a strand of DNA that would match what we were looking for in the cell. After extracting the genetic material from the cell and treating it appropriately we would mix our probe with the genetic material. If there was a positive match then the probe would light up.

I’ve used genealogy testing on myself to know more about my ancestors. I had multiple questions regarding my ancestry, being told that my ancestors were mostly French. It was interesting to learn that it was not the case. I was also interested to learn more about Neanderthal variants and how these variants contributed to our biology, such as improving the strength of our immune system.

Q: Can you briefly explain the science behind DNA tests in terms that an average person would understand?

A: There are different types of DNA testing out there, the most common being SNP testing. SNP stands for Single Nucleotide Polymorphism which means literally a one letter variation in the genetic code. DNA is made from different types of molecules named C,T, A and G in short, that are attached in a string using different combinations. If there is one variation in one letter, for example if an A is changed to a G in a sequence of letters, then we call it a SNP. We can test for multiple SNPs by using what we call a chip. The chip contains arrays of probes that are layed there to attract certain SNPs. A probe is a chunk of DNA that matches a particular SNP. Once we have your genetic material, which could be from your saliva for example, we treat that sample and apply it on the chip. The SNP that are in there will attach to their respective probe and emit a fluorescent signal. This means there is a positive match for that particular SNP. We can tests for a multitude of SNP related to your ancestry or health.

This is different than Whole Genome Sequencing (WGS) which is much more expensive and test every single letter that you have in your genome including the letters and sequence which we might not know much about right now or even do not contribute to our biology.

Q: Given your expertise in the subject, can you give us an idea for some of the pros and cons in consumer DNA testing.

A: Pros: Knowledge is power. Some health related SNPs could be very important to know about. For example, are you homozygous for the MTHFR mutation? If yes, this means that you have the SNP that shows that one key enzyme in your folate metabolism is impaired. This could lead to several health outcomes, but taking a supplement such as methylfolate could help remediate that. There are so many other examples. You can take action on some of the things you learn through genetic testing.

Cons: Genes do not define you. Your environment also plays an important role. If you discover some SNPs that could impact your health it does not mean that you are doomed.

Also there could be some errors in your results. Probe hybridization as explained in an earlier question is not always perfect and could lead to false positive. But the technique is getting better and better.

It does not test for gene copy number, which is basically the amount of one particular gene or SNP that you have. This could also play a role in health outcomes.

Q: Can you speak a bit about the merits of individual companies DNA tests? AncestryDNA, 23andMe, and MyHeritage are the three biggest providers. Can you tell us your thoughts on each of those tests?

A: I know that 23andMe is very interested in health outcomes and that they were the first in the field, but it looks like AncestryDNA is catching up in this field as well. AncestryDNA is also the classic test for discovering your genealogy, and they do a good job tying your Ancestry and family tree to your DNA.

One of the big difference would be the type of chip they use for testing their SNPs. However, the results from the three tests tend to be fairly similar, so it’s quite possible that they all use the same type of chip.

Then the second biggest difference would be how they report the data. AncestryDNA and MyHeritage tend to focus on ethnicity and genealogy, while 23andMe has been more health-focused from the start. The reports might differ in how they predict your ancestry, they might be using different algorithms that could give rise to different probability pattern in your genealogy.

Concerning health, the technology of DNA tests can help you figure out some of the genetic health risk that you carry. However this information is a bit limited for now but they are always expanding their health report library. If you want to get more information out of your SNPs you will have to go to a 3rd party provider who can be a little broader in the SNP analysis, but you definitely need to know what you do and know how to interpret the data. So always ask your health care provider before going to conclusions.

There are other companies that will test for YDNA which are the SNPs on the Y chromosome which is passed from father to son. Women do not have those obviously. Then there is mtDNA which is the DNA in the mitochondria which is passed from mothers to their children. Those two last ones will provide more information on genealogy.

And then, like mentioned earlier, there is the whole genome sequencing (WGS) which is one step above. I don’t think that for now we can use all of the information that those provide, but as research evolves, it will become more useful. The good thing is that once you test WGS you have it for life it does not change. However the companies that tests for specific SNPs might over time change their chip version and go for a chip with more SNPs or better accuracy so you could eventually miss on that.

There are also other companies that provide reports based on nutrition and fitness only. Some of them will accept data from AncestryDNA for example and if you don’t have your data already, they’ll provide you with their own chip so that you can provide your own sample. Sometimes SNPs related to nutrition would only be found on their specific chip and not on other ones.

For most consumers the best option right now is to go for a SNP based DNA test like AncestryDNA which will also be able to report on things that matter to you. All other companies providing health, fitness and nutrition reports are not necessarily based on strong evidence-based research for now and one has to be careful with the recommendations provided. The genetic results are likely correct but most often it’s how they interpret the data that is not always accurate.

Q: One of the hot topics in the DNA testing field is privacy. Can you speak a little bit about DNA testing and privacy concerns?

A: The main concern for most people is what if, for example, insurance companies would get a hand on your genetic results, could they be denying you coverage based on what they learn? Fortunately I don’t think we are there yet. As mentioned earlier, genetic testing can not predict health outcomes, and genes do not define you as environmental factors also called epigenetics are so important. Whether or not you have a gene that predisposes you to breast cancer, it does not mean you are going to have it. Knowing that however, you can take measures to live a healthy lifestyles and screen more often. So I’m not too concerned for now. It could change in the future as research evolves and we are better at forecasting health outcomes based on genes and lifestyle.

Also, most DNA testing company take measures to keep your data private. I know that for 23andme, your account is obviously protected by a password but you also have to go through different loops to download your raw DNA data. I downloaded it at home and have it stored on an external drive that I have with me when I leave.

Q: Can you give us an idea for how the field of genealogy, which has been around for hundreds of years, ties in with the newer field of DNA testing?

A: It definitely has created a breakthrough. While before, for genealogy research you had to dig in books and registry and go see people to ask questions, now you can know your ancestry after a simple test. You know much quicker where to look for. Most of those platforms also enable sharing your ancestry so it’s not uncommon to find cousins and relatives that you didn’t know existed. If you are really interested in genealogy, it’s not a bad idea to get yourself on multiple platforms as relatives might be on one but not the other. You’ll still have to ask questions because obviously our ancestors did not have the technology but it will be more straightforward.

Also, it can break some myths that you had about yourself and your family. If I take myself as an example, I was born in French Canada and always thought my ancestors were French. But when I ran the test I realized that I was equally French and Irish. I also have some Italian and Spanish blood from a long time ago. I’m hoping to get my brother tested so I can learn more about my haplogroups.

Q: A lot of people are excited about DNA testing and the ability to predict disease. Can you talk a bit about the possibilities of DNA testing tying in with health?

A: This was addressed in a previous question partly. The more GWAS (Genome Wide Association Study) studies are done, the more we will know about the probability of getting a certain disease. Again this is just a probability and environmental factors still play a huge role in determining health outcomes. However I do think that knowledge is power, and by knowing your chances to get a certain disease, you can definitely take action. With time, as we gather more research and more SNPs are discovered we will be better at predicting health outcomes in conjunction with epigenetics or environmental factors.

One important note, let’s not forget about the microbiome. These are the tiny bacteria that live in our gut and on our skin and we have trillions of them, so they add a tremendous amount of DNA material to our bodies also playing an important role in our biology.

Q: What do you think is the future of DNA testing?

A: It is very exciting. The more we learn about SNPs and how it affects our health, the more informed we can be. In the future I see nutrition and fitness plans that are specific to people based on their genetic profile. Some companies already claim to provide that information, but one has to be careful and I don’t think the research is totally ready for that kind of reporting.

I also see more preventative health care knowing what we know about our genes. Our own DNA testing combined with the gut microbiome DNA could give rise to very personalized nutrition, lifestyle plan, and ways to optimize our lifespan.

As for genealogy, it will be easier to trace back our ancestry and family trees will be available at the click of a button.

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