Oncogenesis as a Selective Force: Adaptive Evolution in the Face of a Transmissible Cancer

Abstract

Similar to parasites, malignant cells exploit the host for energy, resources and protection, thereby impairing host health and fitness. Although cancer is widespread in the animal kingdom, its impact on life history traits and strategies have rarely been documented. Devil facial tumour disease (DFTD), a transmissible cancer, afflicting Tasmanian devils (Sarcophilus harrisii), provides an ideal model system to monitor the impact of cancer on host life-history, and to elucidate the evolutionary arms-race between malignant cells and their hosts. Here we provide an overview of parasite-induced host life history (LH) adaptations, then both phenotypic plasticity of LH responses and changes in allele frequencies that affect LH traits of Tasmanian devils in response to DFTD are discussed. We conclude that akin to parasites, cancer can directly and indirectly affect devil LH traits and trigger host evolutionary responses. Consequently, it is important to consider oncogenic processes as a selective force in wildlife.

Disease swamps molecular signatures of genetic‐environmental associations to abiotic factors in Tasmanian devil ( Sarcophilus harrisii ) populations

“…2016), have provided additional evidence for a rapid evolutionary response to DFTD across devil populations, suggesting that DFTD is selecting for particular genetic variants post‐DFTD arrival (summarized in Russell et al. 2018 and Storfer et al. 2018b).…”

Cancer- and behavior-related genes are targeted by selection in the Tasmanian devil (Sarcophilus harrisii)

“…Well-known signaling pathways related to both cancer and development, such as MAP-kinase, TGF-β and Wnt pathways, were also targeted by selection. In a marsupial such as the Tasmanian devil, the development of neonates represents a critical window for selection [ 90 ]. As a consequence, we must consider the possibility that selection has targeted some genes for their developmental role or even for their specific tumor-suppressive action during development [ 90 ].…”

Transmissible cancers in mammals and bivalves: How many examples are there?

“…[ 55 ] In marine ecosystems TBN was able to cross the species barrier between two sympatric bivalves belonging to the same Veneridae family as well as between species located on two different continents [ 6,7 ] suggesting that TBN will persist in marine bivalve populations. Due to the strong selective pressure exerted by DFTD, Tasmanian devils rapidly evolved phenotypic and genetic adaptations to the disease, [ 17 ] including changes in reproductive strategy with a transition from multiple reproductive cycles to a single breeding pattern. [ 16 ] Currently, it is still uncertain whether the two transmissible cancer lineages will disappear from the devil population or drive the species to extinction.…”