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Although cancer rarely acts as an infectious disease, a recently emerged transmissible cancer in Tasmanian devils (Sarcophilus harrisii) is virtually 100% fatal. Devil facial tumour disease (DFTD) has swept across nearly the entire species' range, resulting in localized declines exceeding 90% and an overall species decline of more than 80% in less than 20 years.
Researchers have found that Tasmanian devils have developed some genetic resistance to the disease in just four to six generations.
Evolving resistance within so few generations is rare for vertebrates, says Beata Ujvari, an evolutionary ecologist at Deakin University in Melbourne, Australia, who was not invovled in the study. Australia's rabbit population quickly developed resistance to myxomatosis, a fatal viral infection. But it took 50–80 generations to do so.
The devil facial-tumour disease jumps from one Tasmanian devil to another when they bite each other during social interactions.
http://www.nature.com/news/tasmanian-devils-show-signs-of-resistance-to-devastating-facial-cancer-1.20508
http://www.nature.com/ncomms/2016/160830/ncomms12684/full/ncomms12684.html
(Score: 0) by Anonymous Coward on Friday September 02 2016, @03:35PM
Maybe there is something in the environment that contributes to getting the cancer that was only scarcely present at one time, perhaps in certain locations, that is much more abundant or widespread today. Those that were exposed to it developed the gene over a few generations in the past and those genes got spread throughout the wider population to some extent as a form of remembering that this thing does or did exist in nature someplace and may resurface. In a sense you can argue it's like the population's immune system remembering something that happened a long time ago at least to some of its members and retaining some of the information necessary to survive it up to today within members of at least some of its current population.
(Score: 0) by Anonymous Coward on Friday September 02 2016, @09:35PM
I don't think there is any proof of "remembering" in genetics (in the way the immune system does it). Current models state that if a gene isn't needed any more it will converted to something more useful or will disappear over time. Keeping a "memory" costs resources to the organism, this cost reduces fitness of the individual.
The thing I mentioned above comes closest as a "memory", e.g. that a gene is retained by mild selective pressure or bet hedging.
(Score: 0) by Anonymous Coward on Saturday September 03 2016, @04:27AM
While you are generally right if a gene isn't any or that much less beneficial than another gene then it may remain in the population. There are genes that are neither beneficial nor detrimental relative to other genes, otherwise natural selection would make everyone identical.
Some people may have brown hair, some people may have black hair. In most situations hair color may not matter much but if a situation does arise where it does matter hair color could be a factor.
Another example could be butterfly color. In many situations it doesn't matter, except for when it does (ie: how well you blend into the environment and evade predators). When it doesn't matter the population may retain various colors from when it did matter.
Some characteristics from hedge betting could have been past characteristics that were at one time used for survival but aren't necessarily detrimental when compared to another surviving gene.
(Score: 0) by Anonymous Coward on Saturday September 03 2016, @04:29AM
errr ... if a gene isn't any or that much less detrimental than another gene *
(Score: 2) by butthurt on Monday September 05 2016, @04:55AM
More than 100 cases of transgenerational epigenetic inheritance phenomena have been reported in a wide range of organisms, including prokaryotes, plants, and animals.
--https://en.wikipedia.org/wiki/Epigenetics#Transgenerational [wikipedia.org]