A group of researchers has re-created with remarkable accuracy
part of the genome of the common ancestor of all placental
mammals, a small shrew-like creature that prowled the forests of
what is now Asia more than 80 million years ago. By comparing
DNA sequences of 19 species of existing mammals, including
humans, the researchers have reconstructed a large segment of
DNA in the species from which all of today's placental mammals
arose. They estimate that the reconstruction is 98 percent
accurate. The project, which was led by When geneticists hear
that most DNA from the genome of a species extinct for many
millions of years can be re-created with 98 percent accuracy,
"jaws occasionally drop," said Haussler. "It sounds implausible.
But there's enough information to reconstruct the ancestral
genome on the basis of mammals that live today. We just need to
sequence the genomes of these living mammals." The reconstructed
ancestral genome will offer an invaluable vantage point from
which to watch evolution at work.