In a groundbreaking legal case, Russell Marubbio, an identical twin, was convicted of a sexual assault that took place in Woodbridge, Virginia, in 1987. If successful, this case will create a transformative precedent in the United States. For the first time, differences in DNA between identical twins have played a major role in affecting a conviction. The legal and scientific communities are deeply interested in this case. If successful, it might establish a critical precedent for future investigations of identical twins.
The attack took place almost 40 years ago. Until recently, that DNA sample collected from the crime scene remained untouched. Virginia-based Parabon NanoLabs conducted a comprehensive forensic genetic analysis with state-of-the-art technology. Their objective was to identify functional variations of Marubbio and his homozygous twin brother. The scientists employed “ultra-deep sequencing,” which allowed them to explore the twins’ genomes for somatic mutations—alterations that develop in utero after the embryo splits into two.
“In terms of the science, that’s well studied and well understood,” said Claire Glynn, a geneticist involved in the analysis.
Identical twins share nearly exactly the same genetic material, but endlessly tiny differences can appear through mutations that happen after the embryonic division. According to Ellen Greytak, a scientist at Parabon NanoLabs, “On average, twins will have eight of those types of differences across the whole 3 billion bases.” These mutations can form unique signatures in the DNA that help scientists tell the twins apart.
The legal ramifications of this case go far beyond Marubbio’s conviction. It highlights the advancements in forensic investigative genetic genealogy (Figg), which “gets us to a potential person of interest,” according to Glynn. This commercial genealogy service has changed the way law enforcement is using this technique to go after criminal investigations. With affordable home testing and accessible online databases, genealogists like CeCe Moore have been able to trace family trees effectively. Moore spoke to the difficulties she encountered when the DNA result brought her to identical twins.
“It’s what I call a highly scientific tip,” Moore emphasized regarding her investigative approach.
At first, Moore found this a challenge as none of the potential matches in one branch of the family tree lined up. She then received an email letting her know one of those matches had mistakenly exchanged their DNA kit with their partner. This realization brought with it a major epiphany.
This case illustrates a rare phenomenon—the increasing population of genetic or identical twins. These twins are mostly the unintended consequence of success – plenty of it – in fertility treatments. Specialist in genetic interpretation, David Kaye, made an astute observation. He explained that the population of identical twins is larger than what many may think. He spoke widely about the quickly evolving field of forensic DNA analysis. Historically, he explained, cases with identical twins often went cold.
“Occasionally, you get these identical twin defense cases. And it used to be, they would give up,” Kaye said. “Now, it is possible, and it will.”
This advancement in forensic science is not only beneficial to law enforcement agencies, it gives victims, both past and present, new hope for justice. Glynn further explained that understanding genetic differences between identical twins has long been a goal for researchers aiming to enhance forensic capabilities.
“We would see the mutations from very early on in life,” she said, underscoring the significance of these acquired mutations in forensic analysis.
These developments illustrate the strength of today’s genetic science, even when tested by atypical situations such as identical twin cases. Greytak elaborated on the intricacies involved: “It’s really a small amount, but it’s a very distinctive, clear difference.” Finding these subtleties has opened up new routes for cracking cold cases. All of these cases would likely have gone unsolved without this kind of breakthrough.
This case isn’t only about Marubbio’s conviction. This is an important victory, not just for Collette, but for how the judicial system can responsibly and effectively use genetic evidence. Moore expressed optimism about the future of DNA analysis in legal contexts:
“To actually have it used in court and have it accepted by the judge is a huge step forward.”
Our society is transforming with an increased awareness of genetics and its varied applications. This case is indeed a landmark, precedent-setting example of the intersection between science and justice. Even today, advanced DNA techniques allow law enforcement to distinguish between identical twins. This historic settlement can set a new path in addressing these future cases and offer hope to victims across the nation who are still seeking justice.