Their appearance is often attributed to human encroachment on animal habitats, changing socioeconomic conditions, increased connectivity of the world, and genetic changes in the microorganisms.
Genetic changes in the virus could also be responsible.
That did not change, Dr. Forrest said, until molecular biologists showed smoking caused genetic changes in the lung.
None of those experiments involved deliberate genetic changes in the structure of the microbes — the basis of dual-use research.
Afterward, genetic changes in the cells signified that they were browning.
The ability of SARS coronavirus to jump to humans undoubtedly required genetic changes in the virus.
Genetic changes in the bacteria also may have contributed to the increased incidence.
In 1974, Dr. Brenner broke ground by using the chemical EMS, or ethyl methane sulphonate, to induce mutations, or genetic changes, in the genome of C. elegans.
The ability of the SARS coronavirus to jump from horseshoe bats to humans undoubtedly required genetic changes in the virus.
DecanterChina.com, a bilingual website about the Chinese wine industry, said researchers hoped exposure to "space radiation" might trigger genetic changes in the vines that would help them "evolve new resistance to coldness, drought and viruses".
Genetic changes in the population cannot explain the increasing rates, though, because such changes occur too slowly to account for the rapid increases in asthma, the authors said, suggesting that environmental factors are more likely candidates.
