Title

More evolution underground: Accelerated mitochondrial substitution rate in Australian burrowing freshwater crayfishes (Decapoda: Parastacidae)

Document Type

Journal Article

Publisher

Academic Press

Place of Publication

United States

School

School of Science

Comments

Originally published as: Gan, H. M., Tan, M. H., Lee, Y. P., Schultz, M. B., Horwitz, P., Burnham, Q., & Austin, C. M. (2018). More evolution underground: Accelerated mitochondrial substitution rate in Australian burrowing freshwater crayfishes (Decapoda: Parastacidae). Molecular phylogenetics and evolution, 118, 88-98. Original article available here.

Abstract

This study sought to venture beyond the scope of previous research by examining two 2016 events that incorporated elements of different event types. The material events-the ISPS Handa Perth International golf tournament and the Telstra Perth Fashion Festival-were large-scale events with international stature and appeal. Both of those events present concomitant event characteristics: the golf tournament could be labeled as a sporting event and a community event or even a corporate event, while the fashion festival could be deemed as a community event and also a form of cultural celebration or possibly a business event. Notwithstanding that the events are dissimilar in terms of function and goal, the authors assert that the common defining characteristic was that the event volunteer recruitment was geographically localized using local area bounded recruitment drives. Consequently, those events were almost exclusively supported by Perth residents who identified the events as community events because of their considerable contribution. This study sought the opinions and perspectives of the volunteers of the two events with a specific focus on volunteering motivation. This research is timely given the worrying trend of diminishing rates of event volunteering due to attrition in the volunteer base. The outcomes of this study will provide event managers involved in organizing community-based events, where the focus of recruitment is on local volunteers, with more in-depth knowledge about the diversity of motivational factors brought about by the inherent heterogeneity in the volunteer base. Furthermore, insight is gained on the volunteer decision-making process and the factors volunteers take into consideration in deciding to commit themselves to an event.To further understand the evolutionary history and mitogenomic features of Australia's highly distinctive freshwater crayfish fauna, we utilized a recently described rapid mitogenome sequencing pipeline to generate 24 new crayfish mitogenomes including a diversity of burrowing crayfish species and the first for Astacopsis gouldi, the world's largest freshwater invertebrate. Whole mitogenome-based phylogeny estimates using both Bayesian and Maximum Likelihood methods substantially strengthen existing hypotheses for systematic relationships among Australian freshwater crayfish with evidence of pervasive diversifying selection and accelerated mitochondrial substitution rate among the members of the clade representing strongly burrowing crayfish that may reflect selection pressures for increased energy requirement for adaptation to terrestrial environment and a burrowing lifestyle. Further, gene rearrangements are prevalent in the burrowing crayfish mitogenomes involving both tRNA and protein coding genes. In addition, duplicated control regions were observed in two closely related Engaeus species, together with evidence for concerted evolution. This study significantly adds to the understanding of Australian freshwater crayfish evolutionary relationships and suggests a link between mitogenome evolution and adaptation to terrestrial environments and a burrowing lifestyle in freshwater crayfish.

DOI

10.1016/j.ympev.2017.09.022

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