Eva Drozdová’s team from the Biological and Molecular Anthropology Laboratory of the MU Faculty of Science has already conducted several similar research projects. “In the case of Mendel, a world-renowned figure, the pressure and the responsibility were greater. We needed to get many permits, which took about a year, and when we got them all, we could finally remove the remains of Mendel and other Augustinians from the grave,” Drozdová said, noting that her team is now also working with colleagues from the Genomics Core Facility at CEITEC.
The situation at the cemetery was not what the researchers were expecting. “We were pleasantly surprised because we were a bit concerned that we wouldn’t find Mendel. But we discovered his entire skeleton in a coffin; he even had clothes and shoes on,” said the researcher.
According to Drozdová, how to deal with such remains depends on the type of coffin and the environment the body was buried in. When bones are in a wooden coffin, like with the first monk buried in the same part of the grave as G. J. Mendel, they pull the coffin out of the ground and bring it straight to the laboratory.
“However, if they are in a metal coffin, as in Mendel’s case, which contains, besides remains, also clothing, shoes, and other artefacts, then we must very carefully and very quick lift the coffin out of the ground because the bones can rapidly dry out. After being excavated, Mendel’s remains were immediately removed from the coffin and placed in a special room at the cemetery. They were then dried slowly in the lab, so they didn’t disintegrate,” explained Drozdová.
She added that clothing and crosses were also removed from the father of genetics’ metal coffin; there are plans to restore these rare items. Strict measures were in place at the cemetery to prevent contaminating the remains before genetic analysis was conducted. For example, DNA samples of everyone who was in close proximity to the remains were taken. “Everything was carefully documented so that we could describe the situation in the coffin and then reconstruct it based on images,” said Drozdová.
Dana Fialová and her colleagues from the Biological and Molecular Anthropology Laboratory exhumed the remains of Mendel and other Augustinians. “We had to wear special suits and gloves. We prepared them and other instruments by cleaning them, making sure they were not contaminated with DNA. While still at the cemetery we put the samples that we took for studying DNA into a refrigerator we had there; after bringing the samples to the lab, we stored them in a freezer to stop oxidation and the effects of bacteria and mould. Freezing is a best practice for preserving DNA,” said Fialová.
The research team, which besides Drozdová and Fialová, also includes Kristýna Brzobohatá, Eva Chocholová, Kateřina Novotná, Anna Šenovská, and lab technician Lenka Šťastná, focussed on DNA samples acquired from Mendel’s teeth and long bones.
“This is recommended to ensure that two types of tissue are available. For the samples, we have a special laboratory with a sterile environment at the University Campus. The tooth was first disinfected and decontaminated to remove any foreign DNA; then it was put into special water that contains no DNA; and finally it was dried in a box with a UV light. We cut off the root of the tooth, which we then refroze to -80℃. Then we pulverized the material in a special oscillating ball mill. The powder was then put in a lysing solution,” said Fialová, describing the procedure.
The sample of Mendel’s DNA gained in this way was then compared with the hairs that the scientists acquired during previous research on Mendel’s personal items stored at the Mendel Museum and the Augustinian Abbey in Old Brno. This research began last October and finished this January.
“Wearing protective overalls, we examined items that Mendel most likely used. We focussed on body and head hair, which we thought we could find in his favourite books. We had many papers available, but in the end most material was collected from Mendel’s favourite major books – Darwin’s On the Origin of Species and Astronomy, which Mendel supposedly often studied – which remained unused since his time. My colleagues and I examined every page, looking for material that we then stored in sterile test tubes,” said Fialová, describing the research process.
Using a microscope, they then selected fourteen hairs from the collected samples and focussed on obtaining mitochondrial DNA, whose sequence was then compared with the DNA samples from Mendel’s exhumed remains. “We determined the complete mitochondrial DNA sequence from six samples from the abbey. And now that we have DNA from bones and teeth from the grave, we can easily compare them. And it was a success! We determined a match between one DNA sample taken from the first unnumbered page of Mendel’s Astronomy and the samples collected from Mendel’s remains. We can therefore conclude that with great probability the remains we found belong to G. J. Mendel and also that Astronomy was truly his favourite book,” she added.
According to Drozdová, other evidence also demonstrates that the remains are truly those of the man who discovered the fundamental laws of heredity. In the coffin of the abbot, who died on 6 January 1884, the scientists found a newspaper from October 1883. “His biological age was confirmed. The remains as well as the samples collected in the abbey will continue to be studied. But there is no question that they are from Mendel,” added Drozdová.
The researchers also took a 3D scan of Mendel’s skeleton so they will have models of his remains. “His skeleton, however, is not well preserved. The upper part of his body, down to his waist, is in good condition, but his lower limbs and pelvis are poorly preserved. It seems as if these bones were damaged by the fat tissue from his abdomen. Nonetheless, we can still estimate Mendel’s height to have been 168 centimetres and determine what his physique was like. For example, we measured the soles of his shoes, which were 27 centimetres long,” said Drozdová, noting that research will continue to be carried out until at least the end of the year.