by Gidon Schwartz, Education & Outreach Executive
One of my Rabbis once told me that we should not simply go through the motions as we move through the Jewish calendar. Instead, we should take the messages of each holiday and integrate them into our daily lives. Yet many people find the period of the ‘Three Weeks’, which concludes with Tisha B’Av this Sunday, one of the most difficult times to connect with. Are we really meant to feel devastated about the destruction of the Temples that happened nearly 2,000 years ago? Does any of it truly impact on our lives today? What personal lessons can we take from these ancient events?
The late Chief Rabbi Lord Jonathan Sacks z”l offered a profound insight into how we relate to our past, through the comparison of two seemingly similar terms: history and memory. History, he explained, is simply an account of what happened. Memory, on the other hand, is an active process, it helps us answer the question, “who am I?” It takes our personal or communal experiences and uses them to shape our identity and future choices.
He pointed out, quoting his predecessor Rabbi Jakobovits, that three times in the Book of Genesis, God is described as remembering: “God remembered Noah,” and brought him out of the Ark; “God remembered Abraham,” and saved his nephew Lot; “God remembered Rachel,” and gave her a child. When God remembers, it is for the future – for life. In essence, history is passive; memory is active.
Tisha B’Av is a day of memory. It marks numerous tragedies that have befallen the Jewish people, events that have continued to shape our community ever since. Ritualistically, almost every aspect of Jewish practice has changed in the post-Temple era. Culturally, the Jewish people transitioned from a sovereign nation to a dispersed global religion (although, in the past 77 years, we have begun to transition back). But even scientifically, the communal devastations we mourn on Tisha B’Av have impacted our gene pool in ways we still see today.
When the fifth and tenth legions of the Roman army captured Jerusalem under Titus in 70 CE, approximately 97,000 Jews were taken as slaves and dispersed across the Roman Empire, according to Josephus, including into areas where Ashkenazi, Sephardi, and Mizrahi communities would later form. These individuals did not remain together but were scattered into small groups. Some of them would have carried genetic mutations. If, for example, a few of those with mutations ended up in the group that settled in what is now modern-day France, that small, isolated group now distinct from the wider Jewish population, would have had a much higher frequency of those mutations. As their descendants formed the large Jewish communities we know today, these faulty genes became relatively common. This same pattern likely repeated across the Roman Empire, wherever Jewish groups were sent. This biological phenomenon is known as the founder effect.
But Tisha B’Av also marks the anniversary of more recent tragedies that impacted the gene pool of our community. In 1095, Pope Urban II declared the First Crusade, during which 10,000 Jews were killed in the first month alone. The Ashkenazi Jewish population was so devastated by the Crusades that it was reduced to as low as just 350 individuals by the 13th century.
Likewise, on Tisha B’Av in 1492, King Ferdinand and Queen Isabella enacted the Alhambra Decree, as part of the Spanish inquisition, forcing Jews to either flee Spain or face death. This led to a dramatic reduction in the Sephardi Jewish population.
Just like the temple destruction and subsequent diaspora, this affected the community right down to our DNA (both figuratively and literally). Reduced population size meant reduced genetic diversity. If certain mutations existed among the surviving community, their frequency would have been increased, making them even more common in future generations. This is referred to as a genetic bottleneck.
We can see the legacy of these events today through the life-saving work of Jnetics. 85% of the faulty BRCA gene carriers identified through the NHS Jewish BRCA Testing Programme carry mutations traceable to those 350 post-Crusade individuals. The reason we focus on the specific conditions we do is because their prevalence in the Jewish community is a direct result of these historic founder and bottleneck events.
Tisha B’Av is not just about studying history, it’s about remembering. It calls on us to act. While the tragedies of the past have shaped who we are, we must ensure their genetic legacy does not result in further tragedy, on a communal or personal level. Proactive genetic screening is one way we can protect our families and our future.
The Talmud teaches that on the first Tisha B’Av, when the Israelites cried after hearing the spies’ report about the Land of Israel, G-d said: “You cried tonight for no reason; I will give you generations of crying for a good reason.” The work of Jnetics aims to reduce that crying; to prevent the heartbreak and suffering that can still arise today, by remembering the past and taking responsibility for the future.
