MOR 1125, also known as B-Rex, is a Tyrannosaurus rex specimen currently housed in the Museum of the Rockies, in Bozeman, Montana. It is famous for containing soft tissues, blood vessels and proteins.
MOR 1125 was discovered by Jack Horner and Mary Schweitzer in 2000. The specimen was not particulary large, nor was it very complete. However, a look inside one of the femurs in 2007 revealed that this was a unique dinosaur. There were soft tissues inside, along with structures resembling blood vessels. These were similar to ostrich blood vessels, giving more evidence of the relationship between birds and dinosaurs.
A look at some of the tissue revealed that MOR 1125 was female, and likely died during ovulation at the age of 16, 68 million years ago. Studies of the protein revealed that the complete genome of a Tyrannosaurus contained 1.77-2.32 billion letters, and 10% of the genome contained short, functionless sequences.