Insights from the rise of the Central American Isthmus on the genomic bases of marine adaptation and resilience

• Applicants: Professor Dr. Oscar Puebla, Ph.D.; Dr. Montserrat Torres-Oliva, since 1/2024
• Subject Area: Evolution, Anthropology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 516964244

The Central American Isthmus (CAI) closed about three million years ago, providing the backdrop for one of the most remarkable natural experiments of genomic divergence and adaptation in tropical marine organisms. The rise of the CAI simultaneously separated marine populations that were previously connected and profoundly shaped the physical environments of the two newly isolated oceans. Since then the Tropical Eastern Pacific (TEP) and the Tropical Western Atlantic (TWA) differ across several major environmental axes. These include temperature, pH, dissolved oxygen and productivity, parameters that are now rapidly changing on a global scale. Moreover, within the TEP, seasonal upwelling in the Gulf of Panama relative to a lack of upwelling in the adjacent Gulf of Chiriquí generates striking differences across many of the same environmental variables that distinguish the two oceans. We propose to exploit this powerful natural experiment to study the intersection between past and contemporary evolutionary processes and the role they play in the resilience and adaptability of marine organisms. This project is a collaboration among researchers based in Germany, Panama and the USA. It builds on decades of research that have identified so-called ‘geminate species’ that were separated by the closure of the CAI, representing replicated instances of genomic divergence and adaptation. We will focus on ray-finned fishes because they have relatively compact and conserved genomes. Specifically, we propose to ‘genome-enable’ ten fish species representing four geminate pairs or triplets from two different families (Pomacentridae and Haemulidae). Two of the ten genomes were assembled and annotated as a proof-of-concept. The ten genomes will provide the context to characterize genomic and transcriptional variation and determine how this variation is partitioned across different environmental seascapes. Our experimental approach couples insights gained from sampling genomic variation in natural populations and transcriptional variation in a common-garden experiment. The integrated dataset will allow us to i. establish the relative contributions of historical demography, genomic architecture and selection in shaping the contemporary genomes of geminate taxa, ii. identify genes or metabolic pathways associated with adaptive change to the different environments that characterize the TEP and TWA, iii. determine whether the same genes or metabolic pathways also show evidence of adaptive divergence across similar environmental gradients within the TEP, and iv. characterize the interplay between genetic adaptation and plasticity and how it varies among geminate taxa living in highly variable (TEP) versus highly stable (TWA) environments. These data will allow insights into how tropical marine species adapt to changing environmental conditions, providing the opportunity to ultimately predict how they will respond to global change.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Dr. Marc Höppner, Ph.D., until 12/2023