CJG Blog

Center for Jewish Genetics blog

Twin Studies and The Nature versus Nurture Debate

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Three Children By Carol Guzman 

Warning: Light spoilers for "The Identical Strangers" ahead

Imagine finding out you had a twin brother during your first day at college. Then, days later, you get a call from someone claiming to be your triplet. These are the circumstances that brought Bobby Safran, Eddy Gallad and David Kellman together. "Three Identical Strangers" tells the story of how these identical triplets reunited and explores how they were separated. And more importantly, it raises a question: Can three genetically identical people living separately show us how our gene influence who we become? 

As the film unfolds, we learn the Dr. Peter B. Neubauer, a noted child psychiatrist, conducted a "nature versus nurture" experiment with multiple sets of Jewish twins and triplets. All of the test subjects' birth parents put their children up for adoption through the Louise Wise Services adoption agency. That agency placed Bobby, Eddy and David in different home environments. Scientists studied each triplet's development under the guise of the adoption agency conducting due diligence on their adoptees. The records from Neubauer's study remain sealed at Yale University until October 2065. 

While the true story portrayed in the documentary takes it to extremes, scientists regularly study identical siblings to answer the difficult question: Do genes or the environment have a greater effect on a person? Identical twins share 100 percent of their DNA, while fraternal twins and other siblings share on average 50 percent of their DNA, making them ideal people to shed insight into "nature versus nurture" debates. 

Scientists research the heritability of intelligence, disease and sexual orientation by using identical and fraternal twins. A new study in Nature Genetics examined the influence of nature versus nurture of 560 diseases and conditions in more than 56,000 pairs of twins insured by the same insurance company. Most diseases are a result of both your genes and environmental factors. However, scientists found that genes influence about 31 percent of conditions such as sickle-cell anemia, while 9 percent of conditions, such as lead poisoning, are driven by environmental factors. But what do we make of the remaining 60 percent? 

When Bobby, Eddy and David first met, they realized they shared several eccentric similarities. For example, they all smoked the same cigarettes, they were all wrestlers in high school and shared a similar taste in women. However, their reunion wasn't all blissful. The adoption agency never informed the triplets of their family history of metal illness - a control variable across all test subjects. Major mental disorders appear to have genetic links, and we later learn that all three triplets suffered from mental health issues that would end up impacting them in ways they could have never imagined. 

"Three Identical Strangers" showcases a study that split up Bobby, Eddy, David and several other twin sets and studied them "like lab rats." The triplets may never see the unredacted data in their lifetimes (in 2065 they will be 104 years old), but they experienced the unethical experiment firsthand. For them, like for all of us, nature and nurture both played a role in shaping their lives. They are brothers because of their shared DNA, but their adoptive parents and experiences in the 19 years before they even knew the others existed made an even greater impression on their lives. 

A DNA Test for My Dog

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By Sarah Goldberg

These days, it seems there is a genetic test for just about everything. Companies sell DNA tests with claims that range from uncovering your wine preference to providing insight into the most effective skincare routine and seemingly everything in between.

Ancestry genetic tests designed to help us better understand our geographic origins and connect with distant relatives – are among the most popular direct-to-consumer DNA tests, with more than 12 million kits sold.1

I often refer to these types of consumer offerings as recreational genetic tests – they can be fun, but they serve an entirely different purpose than the clinical health information we focus on at the Sarnoff Center: carrier screening and cancer risk education. With that in mind, I’m sharing my experience with an ancestry DNA test…. for my new rescue dog, Domino.

Domino’s name suits him. White with black spots, people stop us on walks almost daily to inquire about his breed and place their best guesses. Most often, people ask if he’s part Dalmatian or perhaps a Border Collie mix. For several months, my husband and I would sort of shrug and respond with our own theories: “He might be part American Staffordshire Terrier, part Australian Cattle Dog, and part Lab.”

Eventually my curiosity got the best of me. I jumped at a Black Friday deal on a dog ancestry test and a DNA collection kit arrived in the mail a few days later.

Similar to many human genetic test kits, it instructed us to collect cell samples from the participant’s cheek. As you may imagine, this proved a bit more challenging with a playful pup than with a consenting adult. After some bribery (and only minimal eating of the collection swab), I obtained a sample to mail off to the lab. Phew! Three weeks later, an email arrived with the results.

Any guesses before I reveal them?

According to the test, Domino is:

·       25% American Staffordshire Terrier

·       12.5% Boxer

·       12.5% Chow Chow

·       12.5% Great Pyrenees

·       37.5% Breed Groups2: Hound, Terrier, Companion, Sporting, and Middle Eastern and African

I’m certainly not alone in receiving ancestry test results that don’t align with my expectations. In Domino’s case, the results leave much of the ancestral question unanswered. But while his past remains a mystery in more ways than one, I don’t regret doing a dog DNA test. It provided a bit of insight into this sweet pup, and some fun along the way.


1.     MIT Technology Review: 2017 was the year consumer DNA testing blew up

2.     Wisdom Panel


How a Government Shutdown Impacts Scientific Progress

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Government And Science

By Carol Guzman

In late December 2018, a partial government shutdown forced many federal agencies to close. While federal agencies are now open again, lost days may have a long-term impact on scientific progress. Furthermore, with a second government shutdown looming, scientific agencies must prioritize what work will be done while agencies are funded short term. Here is a look at some of the work, research and funding that stopped in agencies, departments, and projects across the country during the historic 35-day partial shutdown.


The Centers for Disease Control and Prevention: Budgets for the CDC were not tied up in government negotiations. The agency was able to release this year’s flu statistics, revealing that the flu hospitalization was lower this season than last year’s flu season.

Food and Drug Administration: During the government shutdown the FDA suspended many workers and instituted cost-saving measures to review applications for new drug and medical devices. Reviews are typically paid for by pharmaceutical companies; however, the FDA was unable to collect 2019 application fees during the shutdown. During the shutdown, the agency approved 23andMe's test for hereditary colorectal cancer test. The FDA cutback on routine food safety inspections on seafood, fruits, vegetables and other foods. 

National Institutes of Health: While the government already approved the NIH's funding for 2019, leaving its 27 institutes and centers relatively unaffected by the partial shutdown, the agency's grant process was in jeopardy. As a federal agency, the NIH was required to publish notices of upcoming proposal review meetings in the Federal Register, the public notice publication for federal agencies. Unfortunately, the publication was closed during the government shutdown. Final grant decisions, including grants for genetic studies, are made at meetings that must be disclosed in the Federal Register. The NIH continued to conduct clinical trials. 

National Science Foundation: The NSF awards and funds nearly $8 billion in science projects each year. Last year, the agency distributed $107 million in funding by early January. This year nothing was funded during the time of the government shutdown. The NSF has proposal review meetings to review thousands of applications from prospective graduate students hoping to win a Graduate Research Fellowship. Without these fellowships, graduate school programs may lower the number of students they admit this year. NSF workers have started processing proposals and delivering monetary awards that were frozen during the shutdown. 


Missed Conferences: Many geneticists from the United States Department of Agriculture were unable to attend the Plant & Animal Genome Conference. Government researchers were not able to attend various conferences because of travel restrictions, impeding academic collaborations that typically ensue at these meetings.

Federal Funding: Many scientists who have their research funded with federal money are also experiencing complications. Scientists were not receiving the money necessary to continue their experiments, which for many has long-term impact on their work.  This impacts many colleges and universities

Ticking Clock on Research Materials: As experiments and paychecks were put on pause scientists were struggling to keep insects, plant and microbes, that are vital to their research, alive. The shutdown created significant setbacks for federal researchers who were at risk of having their research subjects die. Sneaking in to save experiments housed in federal facilities during the shutdown is in violation of federal law.

A Long-Term Impact?

The partial shutdown can potentially have a long-term impact on scientific progress, including genetics research. The NIH is the biggest funder of the biomedical research in the United States; their total budget for FY 2019 is $39 billion. Their budget has allowed them to financially back genetic researchers, studies, National Cancer Institute-designated Cancer Centers, the Cancer Moonshot cancer initiative and the All of Us precision medicine study amid the shutdown. The NIH's clinical trials continued during the shutdown, however, the agency did not admit new patients or implement new research proposals.

Pharmaceutical companies use government-funded research to create life-saving experimental treatments. Unfortunately, even though the FDA was carrying out reviews funded by their FY 2018 budget, their Investigational New Drugs (IND) program, the program which pharmaceutical companies obtain permission to start human clinical trials, did not review applications during the shutdown. The delay of the IND program hindered various potential drugs and clinical trials that could have helped cancer patients and individuals with genetic disorders. As the government deal is only set to keep the government funded through February 15th the delays for life saving treatments and clinical trials for those suffering from cancer or genetic disease may only continue.


What a partial US-government shutdown would mean for science

What the Government Shutdown Means for Science

Here’s how the record-breaking government shutdown is disrupting science

How a partial government shutdown could affect your health: ‘It’s narrow’

Partial Government Shutdown’s Impact On FDA Drug Approvals


Affordable, Accessible Genetic Screening in Illinois

Our affordable, accessible carrier screening program uses advanced technology to provide comprehensive screening for Jewish and interfaith couples. Visit our Get Screened page to learn more and register.


Do You Know What's In Your Genes?

What is the most valuable gift you can give to your family? The gift of good health! There are many health conditions that run in families. Knowing your family health history can alert you to the potential risk for a variety of genetic disorders . Talk to your relatives for warning signs and assess your risk for hereditary cancers.

Did you know: Ashkenazi Jews are 10 TIMES more likely to have BRCA mutations, which significantly increases lifetime risks for hereditary cancers, so what does this heightened risk mean for you? Click here to learn more .