The discovery itself dates back to 2005. But it was and is so contrary to every received opinion about what can possibly be preserved in fossils that the findings were questioned. Apparently, until now. Read this report for the full details. But the gist is that iron in blood, under certain fossilization conditions, acts with special binding properties that prevent proteins from degrading.
"The problem is, for 300 years we thought, 'Well, the organics are all gone, so why should we look for something that's not going to be there?' and nobody looks," she said.
The obvious question, though, was how that soft, pliable tissue could survive for millions of years. In a study published Tuesday in the Proceedings of the Royal Society B: Biological Sciences, Schweitzer thinks she has the answer: iron.
Iron is an element present in abundance in the body, particularly in the blood, where it is part of the protein that carries oxygen from the lungs to the tissues. Iron is also highly reactive with other molecules, so the body keeps it locked up tight, bound to molecules that prevent it from wreaking havoc on the tissues.
After death, though, iron is let free from its cage. It forms minuscule iron nanoparticles and also generates free radicals, which are highly reactive molecules thought to be involved in aging.