Not in the genes

Again, this is not totally new, given that for several years 'we' have known that the expression of genes is a huge area affecting the phenotype of organisms and may considerably modify the genetic 'base'. But the evidence is growing.

current research shows that opossum and human protein-coding genes have changed little since their ancestors parted ways, 180 million years ago. It has been the regulation of their genes - when they turn on and off - that has changed dramatically.
"Evolution is tinkering much more with the controls than it is with the genes themselves," said Broad Institute director Eric Lander. "Almost all of the new innovation ... is in the regulatory controls. In fact, marsupial mammals and placental mammals have largely the same set of protein-coding genes. But by contrast, 20 percent of the regulatory instructions in the human genome were invented after we parted ways with the marsupial."

So the fact that we are genetically very close to chimpanzees is not necessarily very significant...
ScienceDaily: Opossum Genome Shows 'Junk' DNA Source Of Genetic Innovation

Technorati Tags: genetics, phenotype, evolution, mammals, expression