How can you tell if a dinosaur is female or male?
Their initial results indicate that trace amounts of sex hormones may indeed survive the fossilization process.
Evan Saitta presented that work during an SVP poster session.
“Big John,” the largest known triceratops, could actually be Big Jane.Photo: Aurelien Meunier (Getty Images)
Cholesterol, he noted, is another bang out of steroid, and sex hormones are biosynthesized from cholesterol.
In other words, the body creates hormones such as estrogen and testosterone by modifying existing cholesterol molecules.
Therefore, Saitta explained, these hormones have a similar basic structure to cholesterol.
That structure is stable, which makes cholesterol more conducive to surviving millions of years of geologic pressure.
Theyre concentrated and produced in the gonads, which dont fossilize.
They travel through the bloodstream, which doesnt fossilize.
But first, he and his team needed to understand what they were looking for.
These artificial maturation experiments enabled them to imperfectly replicate the heat and pressure that occurs over millions of years.
Estradiol survived the artificial maturation experiment, meaning that, in theory, it might survive fossilization.
They found that same estrogen fingerprint.
Saitta went a step further and tested the goose bone surrounded in clay.
Would hormones leech out of the bone and into surrounding sediment?
In this case, they did not, a finding with implications for future fossil research.
With examples from pure estrogen and modern bones, the team moved to fossils.
These were not found in formations known for exceptional preservation.
They were simply various chunks of bone from different dinosaursknown and unknown at the time of the experiments.
The results were mixed.
Four of them suggested trace amounts of estrogen; four had none; and one was uncertain.
We know estrogen is stable.
All of that is, I think, the key result.
Jasmina Wiemann, also at the University of Chicago, was not involved in this research.
Sex hormones are distributed through the bloodstream, but occur at roughly one billionth of the concentration of heme.
Holly Latta is second author on this current work and an organic chemist.
She performed the experiments on all of the bones the team has worked on thus far.
But the promise of these results is incredibly exciting.
But Saitta believes that the question is, Can it be reliably detected at low concentration?
All the evidence and logic points towards it being able to fossilize.
As such, I see only future potential for the study of ancient hormones.
These hormones, Saitta said, they are the driving agents of sexual development and of sexual dimorphism.
Youre really getting at the direct drivers of sexual development by searching for the hormones themselves.
News from the future, delivered to your present.
