A mechanism suggested for the effect of paternal preconception exposure is the occurrence of transmissible genetic changes or an epigenetic mechanism [ 22- 24].
Mutagenicity is the process of induction of permanent transmissible changes in the genetic material of the cells, whereas genotoxicity is a broader term, which is the ability of a compound to interact with the genetic material and also with other cellular apparatus that maintains the fidelity of the genome [ 9].
It is important to study common biological properties of transmissible viruses rather than genetic changes in a singular virus strain, to generalize the mechanisms leading to increased transmission.
As Declan Butler described in the December 20 , 2011issue of Nature: "… virologists have suggested that any genetic changes that made it more transmissible would probably blunt its deadliness.
The researchers in the Netherlands and Wisconsin made genetic changes in the virus that made it transmissible through the air among ferrets, an animal considered a good model for the way flu behaves in humans.
Studies of the genetic changes that make the H5N1 virus more transmissible in mammals including the two papers now under review by Nature and Science are "in a category of their own," Keim says, because of the pandemic risk and H5N1's fatality rate in humans, which appears to be very high.
Because of its genetic changes, H7N9 appears to be "closer" to becoming a transmissible virus compared to the H5N1 virus, Webster said.
A small number of genetic changes might be able to convert the presently zoonotic H5N1 virus into a pathogen with dangerous pandemic potential transmissible from human-to-human, with a >50% case-fatality rate.
With respect to higher organisms, there is no evidence that such changes are transmissible genetically the view associated with Lamarckism but, among protozoans and bacteria, certain induced changes are heritable.
Those stories describe how Fouchier initially tried to make the virus more transmissible by making specific changes to its genome, using a process called reverse genetics; when that failed, he passed the virus from one ferret to another multiple times, a low-tech and time-honored method of making a pathogen adapt to a new host.
But there is nothing obvious that would point to a more transmissible, more virulent virus, or a change of transmission route.
