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  • Xingyi Shi

Know Your Ancestry And Health: DNA Testing For Dummies From An Expert

Updated: Jul 15, 2022

DNA testing has exploded in recent years, with the total number of people tested by consumer genetics companies doubling over the last few years. This DNA boom has made genetic testing one of the hottest conversation topics at dinner tables and enabled people to think about diseases and personalities at the “gene” level.

The two main focuses of genomic testing are ancestry tracing and health diagnosis:

1. Ancestry tracing - This allows you to trace your family back much further than traditional genealogy records. You can also find out where your ancestors came from, and even when they arrived in your current country.

2. Health diagnosis - DNA testing also uncovers essential health information about you. It allows you to learn your body traits, diet restrictions, and even risks to develop a particular genetic disease.

In the following sections, I will briefly discuss how genomic testing works, things to consider before buying a DNA test, some common genetics companies that provide testing services, and finally, targeted testing regarding specific cancer types.

Genomic testing: How does it work

Genomic testing typically collects your saliva samples to extract available DNA. Your DNA then goes through sequencing and aligning (to an aggregated reference) before being compared to thousands of locations of genes, (i.e. loci), representing human heterogeneity.

For example, multiple gene loci on chromosome 16 result in facial dimples; gene p53 at locus 7.66 to 7.99 on chromosome 17 tends to be associated with increased cancer risk.

Using this summarized information, genomic scientists can create your personalized profile that highlights certain traits, ancestry, and wellness patterns.

Genomic testing for specific cancers

Remember back in 2013, Angelina Jolie revealed that she had undergone a preventive double mastectomy because she had a high risk of breast cancer? She was tested positive for the infamous gene, BRCA1, and her doctor estimated she had an 87% risk of breast cancer and 50% risk of ovarian cancer.

This type of DNA testing is called targeted testing, meaning that patients under suspicion for a specific cancer type will be tested for mutations in particular genes related to the disease. Your doctors will direct you to test for specific markers given your medical history.

Similarly, for example, KRAS, TP53, and EGFR mutations are famous for lung cancer risks, and BRCA1, BRCA2, and HOXB13 mutations are famous for prostate cancer. There are also commercialized biomarkers that consist of single genes or combinations of genes for preventative purposes.

Things to consider before buying a DNA test

I know it all sounds very tempting, and you are probably browsing the net to purchase a DNA test kit already. However, there are a few things to keep in mind before making that order.

💡Buy from a company that would protect your data. The movie Gattaca depicted a future society driven by eugenics where people are conceived, selected, and ranked through genetic discrimination. Although it might be too far from where we are now, protecting our genetic information has nonetheless taken place in the back of our minds.

Surprisingly, a large numbers of genetic testing companies are owned by pharmaceutical giants or data companies, which means your personal DNA information may be directly handed over to corporations to make a profit. So try to buy a DNA test from a company that values data security and professional pedigree. The best genetics companies have top-notch data security, are mostly privately owned, and would not sell your data to investors.

💡Follow the science and the genetic experts. Make sure to find a company with an accredited scientist in charge. For example, you can look up the public profiles of their research team and see if they have accredited media mentions and publications. After all, you want highly qualified scientists and researchers handling your DNA.

Being a researcher analyzing genomic data myself, I have fully witnessed how so many things can go wrong in sample collection, DNA extraction, and data analysis. Not surprisingly, there are companies in the field of genetic testing that are just using available protocols without thinking and are simply looking to make quick money.

Trustworthy companies providing genomic testing services

It is hard for everyone to look up data security and follow qualified professional scientists. Here I will list several top-rated companies that provide DNA testing services.

💡23andMe was founded in 2006 in Sunnyvale, California, and has led the most prominent genetic study after publishing more than 100 peer-reviewed studies in scientific journals. It is one of the earliest testing companies that put sophisticated DNA analyses into the customers’ hands, giving them information about their health, disease, and ancestry and allowing them to sell access to the genetic data to fuel research.

💡CRI Genetics is a DNA testing company that promises more accurate ancestry results. CRI Genetics puts extreme importance on data security and encryption. In addition, CRI is 100% privately owned and does not need to share data with pharma companies or the government.

💡Nebula Genomics is a relatively new company co-founded in 2018 by George Church, a geneticist at Harvard Medical School. One notable highlight about Nebula Genomics is its novel ultra-deep whole-genome sequencing that enables the most comprehensive and accurate report, allowing the discovery of rare traits and conditions. Additionally, given the comprehensive personal genomic reports it generates, Nebula Genomics is also a leading privacy-focused company aiming to make direct-to-consumer DNA testing secure.


DNA testing may sound unfamiliar and inaccessible. I hope this information can give you a brief introduction to DNA testing and a selection of top-rated providers. Hope you find this article helpful and start to learn more about your ancestors and your body!

Additional Useful Resources:

Editor’s notes: Our guest author (Xingyi Shi) is a research scientist working with DNA, RNA, and genomics in general. She graduated from Boston University with a degree in Bioinformatics and is currently working in a pharmaceutical company in Cambridge, MA. She loves science, biology and computer science in general. Outside of work, she also likes going out for a walk and spending time with animals. You can learn about what she does here.


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