Even if you didn’t take art history classes in school, you probably know Salvador Dalí’s work. One of the surrealist’s most famous paintings, “The Persistence of Memory,” is the one with the melting clocks.
But memory is not the only thing that persists — a woman who has claimed to be Dalí’s daughter for over a decade has not given up. To support her contention, Pilar Abel has had two previous paternity tests performed — one with inconclusive results, another that allegedly never sent her results. Now a Spanish court has granted her request to have Dalí’s body exhumed from a crypt in Catalonia so a third test can be conducted.
But Dalí has been dead for nearly 30 years. Can a sample of his DNA still give Abel a definitive answer?
“Yes and no,” said Hendrik Poinar, principal investigator at the McMaster Ancient DNA Center in Ontario, Canada. The success of the test will depend on a lot of factors — including, possibly, which kind of analysis is done.
Poinar isn’t involved in the case, but he is trying to solve a mystery about another famous 20th-century artist. He’s analyzing the remains of poet and Nobel laureate Pablo Neruda to determine if a bacteria was involved in his death in 1973.
The researchers working with Dalí’s DNA will need to consider two main issues: contamination during the exhumation and working with degraded DNA afterward, Poinar said.
Though Dalí died in 1989 — certainly not ancient history — “your DNA degrades the minute you die,” Poinar said. He and his students will often define ancient DNA as “anything that’s buried in the ground.”
A sample will likely come from one of three places: hair, a molar tooth, or a small but very compact bone in the skull near the inner ear. Hair is pretty resistant to contamination, Poinar said, and the bone — called the petrous bone — has the most DNA per gram of any part of the skeleton.
A standard forensics lab might take these samples, extract DNA, and look at a set of more than a dozen “microsatellites,” Poinar said. Each microsatellite can range from 100 to 400 DNA base pairs long and can vary in only so many ways — in which DNA bases repeat and how many times they repeat. (These repeating sequences are called short tandem repeats, or STRs; looking for them is called STR analysis.)
For comparison, the human genome is about 3 billion base pairs long. The possible patterns are numerous enough that determining if two samples come from the same person — or if the donor of one sample is likely related to the other — is very possible.
However, Dalí’s DNA may be in shorter fragments — which may mean this DNA profiling technique will be less reliable. In Poinar’s experience, the average length of a DNA fragment from skeletal remains is about 70 to 80 base pairs — so the average fragment would likely have only part of a satellite region. If many of these microsatellites are compromised, then the analysis loses a lot of statistical power.
Instead, he and other ancient DNA experts working in more specialized labs prefer sequencing full genomes and comparing a collection of single nucleotide polymorphisms, or SNPs (pronounced “snips”), which are variations in just one base pair.
The burial environment — what kind of casket Dalí was buried in could have an effect, for example, or any kind of treatment his body received before burial — can have a impact on the condition of DNA. Only the people on the ground during the exhumation — and those who actually sequence the sample — will know what state the DNA is in, noted Reena Roy, an associate professor in the forensic science program at Pennsylvania State University. Without being there or using other techniques to determine how degraded the DNA actually is, she said, “one can only speculate.”
Roy suspects Dalí’s DNA could be in decent shape — “it’s only 30 years old,” she said. She’d still use STR analysis first, but if that didn’t seem to work, she’d consider using miniSTR testing, which uses the same principles but focuses on smaller DNA segments.
Bottom line: Though the circumstances around the particular paternity case may be a bit surreal, the techniques themselves are not; STR analysis is usually done in paternity cases, Roy said.
“This is so routine these days.”