Aussie Tasmanian devils evolve cancer resistance, according to reports in ScienceDaily, Science (AAAS) news, Nature News 30 August 2016, and ABC News 31 August 2016, and Nature Communications doi.org/10.1038/ncomms12684 published online 30 August 2016.
Over the past 20 years a deadly cancer has rapidly spread through the population of Tasmanian Devils. The cancer, named Devil Facial Tumour Disease (DFTD) is spread when the animals bite one another, which they do a lot. The cancer is usually fatal within six months of the animal being infected with it, and in some regions of Tasmania the disease has wiped out up to 90% of the population.
In the midst of this bad news, there seems to be some good news. According to Science News, “Tasmanian devils are rapidly evolving resistance to a contagious cancer” and it looks like they may not become extinct after all. Paul Hohenlohe of University of Idaho explained: “If a disease comes in and knocks out 90 percent of the individuals, you might predict the 10 percent who survive are somehow genetically different. What we were looking for were the parts of the genome that show that difference. “
Science News described the research: “scientists looked at hundreds of devil genomes from three different sites in Tasmania and compared them with genomes from animals living decades ago, when DFTD hadn’t yet run rampant. They found that the modern survivors had differences in seven genes, five of which are related to cancer or immune function in other mammals, including humans.”
In their Nature Communications report, researchers claim they found “strong evidence for an evolutionary response to selection imposed by DFTD” because they found “allele frequency changes” in two gene regions when comparing the pre- and post-tumour population of devils in three places in Tasmania. Menna Jones of University of Tasmania commented: “The main result of this study is that the devil is evolving at a genomic level. The regions [in its DNA] that are changing in response to the disease are those that are associated with cancer and immune function. It indicates that the devil is adapting, it’s responding to the disease in ways that it may be able to beat the cancer and save itself.”
Editorial Comment: Despite science media claims that genes have evolved, what the original report indicates is that the study actually found an allele frequency change, which is a response to selection pressure. But the honest original reporting of “allele frequency changes” means that since alleles are variations of the same genes, then genes for resisting the tumour already existed in the devil population. So let’s be honest: this study has not found any evolution at all. Change, yes (in percentage of gene variations), but evolution of new genes, NO!
Therefore, when facial tumour disease arrived in the devil population, those animals with pre-existing resistance genes survived, while the others without them were killed off. This is real natural selection, but it is not real evolution. The survivors already had genes that enabled them to resist the disease, and these are the genes that have been passed onto succeeding generations.
So let us repeat so you don’t miss it! The change discovered by researchers was simply a change in the number of animals within each population who now have resistance genes. They did not evolve new genes – they inherited them. This does not devalue the worth of the research as it will certainly help us understand which genes are involved in resisting cancer and how they work. However, there is no need to pretend this is evolution when it is not.
Evidence News vol. 16, No. 16
14 September 2016
Creation Research Australia
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