This can result in spread of disease across species barriers.

So, I just think we have to get over what must be some innate fear about species barriers and understand how nature really works.

Finally, an experiment created to study a strong species barrier recently stunned those in the field.

"People talked about there being species barriers - you're reorganizing nature in some way."

Science did make one major mistake in assuming these diseases could not jump the species barrier.

They knew what animals did, but somehow they never quite made the jump across the species barrier.

"On six separate occasions that we know of it has crossed the species barrier.

Cracking the species barrier has the potential of opening up vast new areas of research.

Attempts to bridge species barriers are often said to involve no little hubris.

Precisely which infectious agents can infect across species barriers, and how often?

I felt I had broken through the species barrier.

The alarming thought is that a "species barrier" has been crossed and may be no longer protecting humans.

"These findings suggest that mink may provide an important model to study species barrier effects," Marsh observed.

This may predict what other pathogens may jump the species barrier next.

Nonreligious objections come from those who believe crossing species barriers to be "unnatural."

If there were a colonial mentality that could covet territory across the species barrier, this was it.

When viruses cross this so-called "species barrier", their effects can be severe, and humans may have had little natural resistance.

If it's possible to correlate concepts like 'God' and 'worship' across species barriers."

"The next step is to go beyond the species barrier to other species who are sentient and thinking creatures," he said.

Yet another species barrier has been broken.

Also, "there is no animal prion disease that appears to cross the species barrier so easily and dramatically," he said.

There was some sort of "species barrier."

The chances that an animal virus will jump the species barrier are greater in places with constant contact between humans and animals.

It might also renew research on crossing species barriers so that animal organs could be transplanted to humans.

Zollner explained, "Most of these viruses and bacteria cannot cross the species barrier.