DNA in bones

"Dinosaurs lived 65 million years ago. What's left of them is fossilized in Rock."

—Alan Grant^(src)

The most abundant remains of dinosaurs are their fossilized bones. Therefore, dinosaur bones are the most obvious place to look for dinosaur DNA. Bones haven't as good preservation properties as ice or amber. Nonetheless, DNA has been recovered from 300,000 years old unfrozen bone specimens.

Multiple scientists have claimed to extract DNA from dinosaur bones. However, most scientists believe DNA can't last 65 million years in bones. The discovered DNA could be contamination.

Jurassic Park media

Films

"The recent discovery that soft tissue, preserved by iron key layers, can produce goldmines of DNA."

—Christopher Reddy^(src)

In the 2010s, after the discovery that soft tissue in dinosaur bones still contains ancient DNA, InGen started to collect DNA from fossils. Dr. Christopher Reddy called the soft tissues "goldmines of DNA". InGen could now supplement the DNA in Amber with the DNA from the fossils, instead of the DNA from frogs. As a result, InGen was approaching 100% genome accuracy in dozens of species.

Other

"By grinding up large quantities of dinosaur bones it might be possible to extract fragments of DNA."

—Lewis Dodgson^(src)

The concept of ancient DNA in dinosaur bones is mentioned in the novels. When Lewis Dodgson, a scientist from InGen's rival corporation, tries to convince the board that InGen has cloned dinosaurs, it is the sole source of dinosaur DNA Dodgson can think of.

In the video game Jurassic Park: Operation Genesis DNA can be extracted from dinosaur bones. They do not contains as much DNA as amber. However, the species of the DNA is know before the player has to spend money to extract the DNA.

Ancient DNA from bones

Tens of thousands of DNA base pairs were recently sequenced from 40,000-year-old skeletal remains of cave bears without using PCR, establishing that, in principle, large-scale genomic sequencing of fossilized remains is possible .

Fragments of mitochondrial DNA are extracted from 300,000 year old cave bear bones from Spain.

Of course, the remains used in these studies are orders of magnitude younger than anything from the dinosaur era, and the technique might not extend to those creatures.

How long can DNA last

The scientific community has accepted that proteins and soft tissue can survive tens of million years in unfrozen bones. How long DNA can last in unfrozen bones, however, is a matter of fierce scientific debate.

Pruvost and his team (2007) reported that freshly excavated bones contain more DNA than specimens that have been stored in museum for years. Their article says:

we demonstrate that freshly excavated and nontreated unwashed bones contain six
times more DNA and yield twice as many authentic DNA sequences as bones treated
with standard procedures.
Finally, we compared the DNA content in the fossil bones of one animal, a 3,200 
year-old aurochs, excavated in two separate seasons 57 years apart. Whereas the
washed museum-stored fossil bones did not permit any DNA amplification, all 
recently excavated bones yielded authentic aurochs sequences. 
We established that during the 57 years when the aurochs bones were stored in 
a collection, at least as much amplifiable DNA was lost as during the previous
3,200 years of burial. 

under construction

DNA from dinosaur bones

In 1994, scientists claimed to have successfully extracted DNA from two Cretaceous bone fragments . However, further studies by at least 5 different laboratories found that the supposed dinosaur DNA was merely contamination from modern human DNA . Similarly, in 1995, scientists in China reported finding DNA in a fossil dinosaur egg . However, further studies found that the DNA was actually from modern fungus .

In 1995, DNA was reported in osteocytes of the tyrannosaurid Tarbosaurus. However, the source of the DNA could not be verified.

Results of Schweitzer and her team (2013). The top row shows bones cells of T.rex, the second Brachylophosaurus, the last ostrich. The scientists used three techniques to stain the DNA: anti-DNA antibodies (1st column), propidium iodide (PI) (2nd column), DAPI (last column).

Schweitzer and her team analysed T. rex and Hadrosaur bones for DNA. The results (published in 2013) are shown in this figure. The top row shows bones cells of T. rex, the second Brachylophosaurus, the last ostrich. The scientists used three techniques to stain the DNA: anti-DNA antibodies (1st column), propidium iodide (PI) (2nd column), DAPI (last column).

It is unlikely that this DNA is of bacterial origin. Just like in ostrich cells, only the cores of the cells are stained. Another analysis identified histones near the DNA, bacteria don't have histones.