A. Rus Hoelzel
Ph.D., Genetics, Cambridge University, Cambridge, UK
MS, Evolutionary Biology, University of Sussex, Brighton, UK
B.A., Biology, Reed College, Portland, Oregon
E-mail: a.r.hoelzel@dur.ac.uk
Website:  https://www.dur.ac.uk/biosciences/staff/profile/?id=17

Rus Hoelzel is an evolutionary biologist and conservation geneticist working especially on understanding evolutionary process and the implications for the conservation of natural populations. He has been editor in chief of the Springer-Nature journal Conservation Genetics since 2000.  His group works on a broad range of taxa, but with some focus on marine mammals and fish, working with both modern and ancient DNA.  Recent projects have focused on using genomic tools to better understand the interaction between selection and drift, and the role of ecology and behavior towards the structuring of populations in sympatry or parapatry.  Another key objective has been to understand the impact of population bottlenecks and the potential for population recovery.  Examples include genomic data showing that sympatric populations of marine-mammal-eating compared to piscivorous killer whales show disruptive selection for loci associated with diet, and a study that by re-sequencing 60 roundnose grenadier (a deep sea fish species) genomes across a depth gradient showed non-synonymous changes in relevant functional loci across the boundary between the mesopelagic and bathypelagic depth zones.  In the latter study there was no differentiation at ~6M neutral SNPs across this boundary, and fish distribute to the depth that matches their genotype as they age, suggesting ongoing selection to maintain this ecotype diversity.  Key publications have been in the journals Nature, Nature Ecology & Evolution, Science, PNAS, PLoS Genetics, Molecular Biology and Evolution and Molecular Ecology.

As a Hrdy fellow, Rus will focus on two projects. He has worked since the early 1990s on the population genetics of southern and northern elephant seals, with particular attention to the impact of population bottlenecks.  He used genetic data to estimate the size and timing of the northern elephant seal bottleneck and quantified the impact, including direct comparisons from historical samples collected before and after the event showing the direct loss of diversity and the impact on phenotypic diversity and fluctuating asymmetry.  The modern population recovered demographically (census size now >200,000), but it is unknown how depletion of e.g. immune system genetic diversity may have affected their vulnerability to epizootic events or what potential remains for adaptive change.  At Harvard he will sequence genomes from individuals that lived before the bottleneck, just after, and ~100 and 130 years later (combining new data with recently accumulated genomic data for modern populations).  These sequences will be analysed to detect signals of post-bottleneck selection, and more broadly to reveal in detail how the species genome was affected by the bottleneck.  The second project will revisit the idea of the ‘evolutionary significant unit’ for conservation.  The objective will be to contribute to the development of an effective and simple strategy for incorporating information on adaptive potential into conservation policy and practice, including a metric that could provide a quantitative assessment of adaptive diversity.