BioGenomics2017 - Global Biodiversity Genomics Conference
February 21-23, 2017
Smithsonian National Museum of Natural History | Washington, D.C.

Program - Single Session

[Back to Session Listing]

Ecological Genomics

Room: Baird Auditorium, NMNH

14:30 - 15:40

Moderator: Katrina Lohan, Smithsonian Environmental Research Center

3.1  14:35  Ecological genomics - footprints of plant-insect coevolution in the CYPome. May Berenbaum *, University of Illinois

Ecology, the biological discipline focused on the study of the interactions among organisms and between organisms and their physical environment, may seem far-removed from genomics but, in reality, these two approaches to understanding life on Earth are highly complementary. Among the most important ecological interactions in terrestrial communities are those between flowering plants and the insects that consume them, which collectively involve >500,000 species. While insect genome sequencing has generated enormous amounts of information about gene families associated with finding, evaluating, and processing plant food, no insect genome can be fully understood in the absence of information about the other organisms with which that genome interacts. Many of the substrates for insect enzymes, e.g., are not encoded in the insect genome itself but rather are the products of the genomes of organisms with which the insect interacts. A case in point is the enormous cytochrome P450 gene superfamily, encoding enzymes that convert lipophilic substrates to more hydrophilic products; whereas some P450s are involved in the biosynthesis of endogenous compounds, such as hormones and pheromones, the majority process exogenous substrates, particularly dietary and other environmental toxins. For herbivores, dietary toxins include the diversity of phytochemicals produced by plants to deter erstwhile consumers. In general, P450s associated with endogenous functions are conserved across insects; by contrast, P450 genes associated with interactions with other organisms, including plants, vary more than fourfold in number, with little functional conservation, across genomes. Molecular analysis sets the origin of P450s at about 400 million years, coincident with the colonization of terrestrial environments by plants and their herbivores. Multiple gene duplication events are thought to facilitate new interactions as genes proliferate, diversify, and ultimately acquire novel functions as new substrates are encountered. Comparing CYPome size and composition in the context of phytochemical diversity can illuminate the coevolutionary processes leading to variation in diet breadth in leaf- and flower-feeding Lepidoptera as well as variation in pollen- and nectar-processing in solitary and social bees.

3.2  14:55  Understanding mechanisms of response to complex environmental conditions using model and non-model plants. Christina Richards *, University of South Florida

Understanding how organisms are able to respond at different time scales is an essential component of deciphering the impact and long-term consequences of changing environment. Rapidly developing genomic tools for model plants grown in controlled conditions can now be used to examine the mechanisms of phenotypic response in a broad array of wild organisms and biologically relevant conditions. Studies in wild settings allow for exploring how phenotypic variation is modulated by variation in gene expression resulting from sequence polymorphisms and regulatory mechanisms. While studies interested in adaptation have largely assumed that trait variation is based on sequence variation, there is now pressing need to explore the role of epigenetic processes. Epigenetic effects can result in heritable, novel phenotypes even without variation in DNA sequence and could therefore provide an unappreciated source of response. My lab group uses reduced representation bisulphite sequencing and transcriptomic approaches to explore the potential role of genetic and epigenetic processes in natural and controlled studies of native and invasive salt marsh species like Spartina alterniflora and Japanese knotweed. We also leverage the power of the eudicot Arabidopsis and monocot Brachypodium distychum model plant species to confirm our findings in these non-model plants. Combined these studies will enhance our understanding of how genetic and epigenetic variation interact in response to environment on different time scales, and ultimately contribute to adaptation.

3.3  15:15  Climate change and the evolution of seasonal camouflage. Jeffrey Good *, University of Montana

Resolving the mechanisms by which animals adapt to novel environments is central to understanding the origin and conservation of biodiversity. Mismatches between the timing of key life history events and optimal environmental conditions have emerged as an important threat to biodiversity, yet the evolutionary dynamics of most seasonal adaptations remain poorly understood. I will discuss our recent research on the evolution of seasonal camouflage in an iconic ecological model, the snowshoe hare (Lepus americanus). Snowshoe hares and several other mammals have evolved seasonal molts between brown and white pelages that are integrated with a suite of other changes in morphology, behavior, and physiology that are all cued by photoperiod. In hares, autumn molts to white winter coats closely track the local onset of winter snow cover. However, some populations that experience more ephemeral snow cover have secondarily evolved brown winter pelage. We have combined population genomic association mapping, pedigree analyses, and functional genomic studies to dissect the genetic basis and evolutionary history of alternative winter white or brown pelage morphs. Field estimates of coat color-related survival combined with genomic signatures of positive selection at causative coat color alleles reveal strong natural selection on the maintenance of locally adaptive seasonal crypsis. Our results provide one the first examples of a clear genotype-to-phenotype-to-fitness link for a seasonally changing trait. These findings provide important insights into how this crucial component of seasonal flexibility may respond to rapid environmental changes in snowshoe hares and other species.

15:35 Questions & Discussion
15:40 - 16:10 Coffee Break

[Back to Session Listing]