by Josh Forman, Head of Science, Education & Outreach
We often discuss the genetic principles of the Founder Effect and the Bottleneck Effect. Together, these evolutionary biology concepts help explain the high prevalence of genetic disorders across all facets of the Jewish community. As Pesach approaches, I find myself reflecting on how our history is filled with such events. The story of Pesach—our exodus from Egypt—is, in many ways, the original Bottleneck Event. Thinking about this idea, I see even greater depth in the historical impact of the Children of Israel as a transient and often persecuted people. Our survival and resilience are not just products of history but of the way we respond to these experiences, emerging stronger each time.
Recently, Jnetics was invited to speak at Holland Park Synagogue. This was significant for a couple of reasons.
First, Holland Park is a Sephardi community, and our invitation demonstrates a growing recognition that our work is highly relevant not only to the Ashkenazi community but also to those of Jewish Sephardi and Mizrahi descent. Genetic disorders affect all Jewish communities and an increasing awareness of this is a critical step toward ensuring the health of future generations for the entire community.
Second, I was particularly inspired by Dayan Kada’s sermon, which reflected on the message of that week’s Parasha, Mishpatim, and the concept of “rights,” such as Human Rights. In Western society, individual rights are considered fundamental—they define what people are entitled to and dictate what is legally, socially, or ethically owed to them. These rights are crucial to the way the world operates, and many communities have had to fight across generations to secure them.
However, as Dayan Kada explained, Judaism approaches this concept differently. Instead of focusing on individual entitlements, Judaism emphasizes duties and responsibilities. Rather than saying, “I am entitled to be treated well,” Judaism teaches, “I have a duty to treat others well.” In an ideal world, both approaches would lead to the same outcome, but the mindset they create is vastly different. Dayan Kada linked this perspective to the resilience of the Jewish people and our proactive nature in caring for those around us – citing this as a possible factor in the amazing endurance of the Jewish people.
This concept applies to almost every aspect of life, including the work of Jnetics. Our mission at Jnetics is a direct response to this proactive mindset – we look to take action, before any child is born with one of the devasting conditions that we screen for. Throughout history, Jewish populations have faced repeated massacres and forced expulsions, drastically reducing our numbers. When a population shrinks and then regrows, genetic conditions—previously rare—can become more common due to the limited gene pool.
This cycle has repeated itself for generations. From the very inception of the Israelite people, we have faced genetic bottlenecks and founder events. When the Israelites left Egypt with Moshe, only 20% of the population went with him. If just one person in ancient Egypt carried a genetic disorder, they were one in potentially eight million. But if that individual was among the 20% who left, they became one in 1.2 million. Over time, events like the Babylonian and Assyrian exiles, the Roman expulsion, the Crusades, the 1391 massacres in Spain, the Spanish Inquisition, forced conversions in North Africa, massacres in Persian cities, the pogroms of Eastern Europe, and, of course, the Holocaust—all contributed to the genetic landscape of the Jewish people.
I list these events not to evoke sadness but to highlight that our DNA carries the history of these struggles. Despite facing immense challenges, we have always persevered. Today, we continue to carry the genetic scars of our past, but we also have the knowledge and tools to address them.
Throughout history, the Jewish people have survived not by chance, but through action. Our values compel us to take responsibility for our communities and future generations. In the same way we work to protect Jewish education, culture, and security, we must also safeguard our genetic health.
In Judaism, pikuach nefesh—the principle that preserving life overrides almost any other commandment—is a core value. Taking preventative action to ensure the health of future generations is not just a recommendation; it is an obligation. If we have the ability to protect our children and grandchildren from preventable suffering, we must take that responsibility seriously.
The reality is that genetic disorders do not discriminate. They do not wait for a convenient time to appear. But by taking proactive steps today, we can ensure that our descendants have healthier, safer lives. The technology and knowledge exist—we simply need to make use of them.
Being proactive in this way is not about fear; it is about empowerment. It is about ensuring that our children do not have to face challenges that we have the ability to prevent. The Jewish people have survived for thousands of years through resilience, responsibility, and forward-thinking. Let’s continue that tradition by taking action today.
By embracing genetic screening, we are not just protecting individuals—we are safeguarding the future of our community.
If we truly believe in the responsibility to care for one another, then taking this simple, proactive step is one of the most meaningful things we can do.
