NYT:

T. rex shared more of its genetic makeup with ostriches and chickens
than with living reptiles, like alligators. On this basis, the research
team has redrawn the family tree of major vertebrate groups, assigning
the dinosaur a new place in evolutionary relationships.

Similar
molecular tests on tissues from the extinct mastodon confirmed its
close genetic link to the elephant, as had been suspected from skeletal
affinities.

“Our results at the genetic level basically agree
with what has been seen in skeletal data,” John M. Asara of Harvard
said in a telephone interview. “There is more than a 90 percent
probability that the grouping of T. rex with living birds is real.”

One of the researchers cited in the article about the molecular study of dinosaur tissue was named Dr. Organ.