Population genetics of sugar kelp in the Northwest Atlantic region using genome-wide markers

Authors: MAO, XIAOWEI - Cornell University; AUGYTE, SIMONA - University Of Connecticut; HUANG, MAO - Cornell University; HARE, MATTHEW - Cornell University; BAILEY, DAVID - Woods Hole Oceanographic Institute (WHOI); UMANZOR, SCHERY - University Of Connecticut; MARTY-RIVERA, MICHAEL - University Of Connecticut; ROBBINS, KELLY - Cornell University; YARISH, CHARLES - University Of Connecticut; LINDELL, SCOTT - Woods Hole Oceanographic Institute (WHOI); Jannink, Jean-Luc

Submitted to: Frontiers in Marine Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2020
Publication Date: 8/21/2020
Citation: Mao, X., Augyte, S., Huang, M., Hare, M.P., Bailey, D., Umanzor, S., Marty-Rivera, M., Robbins, K.R., Yarish, C., Lindell, S., Jannink, J. 2020. Population genetics of sugar kelp in the Northwest Atlantic region using genome-wide markers. Frontiers in Marine Science. 7:694. https://doi.org/10.3389/fmars.2020.00694.
DOI: https://doi.org/10.3389/fmars.2020.00694

Interpretive Summary: An assessment of genetic diversity of marine populations is critical not only for the understanding and preserving natural biodiversity but also for its commercial potential. As commercial demand rises for marine resources, we need to generate baseline information on the genetic state of wild populations to know how future practices affect them. Furthermore, anthropogenic stressors on the coastal environment, such as warming sea temperatures and overharvesting of wild populations, are leading to the destruction of keystone marine species such as kelps. We conducted a fine-scale genetic analysis on Northwest Atlantic sugar kelp using genome-wide high-density markers. The population structure for a total of 149 samples from the Gulf of Maine (GOM) and Southern New England (SNE) was investigated. Our results indicate that the GOM region is more heterogeneous than SNE. These two regions are genetically distinct, being separated by Cape Cod, which is known to be a barrier for disperal for other species. We detected one significant DNA marker (P = 2.03 × 10–7) associated with stipe length, and 248 SNPs with higher-than-neutral differentiation. The findings of this study provide baseline knowledge on sugar kelp population genetics for future monitoring, managing and potentially restoring wild populations, as well as assisting in selective breeding to improve desirable traits for future commercialization opportunities.

Technical Abstract: An assessment of genetic diversity of marine populations is critical not only for the understanding and preserving natural biodiversity but also for its commercial potential. As commercial demand rises for marine resources, it is critical to generate baseline information for monitoring wild populations. Furthermore, anthropogenic stressors on the coastal environment, such as warming sea temperatures and overharvesting of wild populations, are leading to the destruction of keystone marine species such as kelps. In this study, we conducted a fine-scale genetic analysis using genome-wide high-density markers on Northwest Atlantic sugar kelp. The population structure for a total of 149 samples from the Gulf of Maine (GOM) and Southern New England (SNE) was investigated using AMOVA, FST, admixture, and PCoA. Genome-wide association analyses were conducted for six morphological traits, and the extended Lewontin and Krakauer (FLK) test was used to detect selection signatures. Our results indicate that the GOM region is more heterogeneous than SNE. These two regions have large genetic difference (between-location FST ranged from 0.21 to 0.32) and were separated by Cape Cod, which is known to be the biogeographic barrier for other taxa. We detected one significant SNP (P = 2.03 × 10–7) associated with stipe length, and 248 SNPs with higher-than-neutral differentiation. The findings of this study provide baseline knowledge on sugar kelp population genetics for future monitoring, managing and potentially restoring wild populations, as well as assisting in selective breeding to improve desirable traits for future commercialization opportunities.