Expanding the phylogeography and connectivity of Perkinsus species across North and Central America

Yisrael L, DiMaria RA, Santos‐Ciminera P, Aguirre‐Macedo ML, Vidal‐Martínez VM, Ruiz GM, Torchin ME, Hill‐Spanik KM, Gnanadesikan A, Pagenkopp Lohan KM. 

Diversity and Distributions. Dec 20. 

https://doi.org/10.1111/ddi.13807

Abstract
Aim
Parasites in the genus Perkinsus infect marine molluscs globally, with novel detections expanding and reshaping our knowledge of their biogeographic patterns and the factors influencing those patterns. Here, we aimed to characterize the phylogeography and genetic connectivity of Perkinsus spp. in bivalves across North and Central America, which included infection hot spots (e.g., the Gulf of Mexico, Chesapeake Bay) and areas where these parasites had not been previously reported (e.g., along the California coast).

Location
All coasts of North America and both coasts of Panama.

Methods
Utilizing standard PCR and DNA sequencing, we genetically screened 933 bivalves from across North America for parasites in the genus Perkinsus, then combined this with 752 bivalves previously screened from Panama, which included 16 species from three different countries. Phylogenetic methods were used to confirm the identifications of all the bivalves collected and the Perkinsus spp. detected. We combined our data with publicly available sequence data for these parasites to create global haplotype networks to assess regional and continental genetic diversity and phylogeographic patterns.

Results
We detected three species across North and Central America, including Perkinsus beihaiensis, P. chesapeaki, P. marinus, while P. olseni was only detected in Panama. We report for the first time P. chesapeaki was detected in Isognomon sp. from Mexico and P. beihaiensis detections in Ostrea lurida from California, USA. Additionally, our results indicate extremely low-genetic diversity of P. beihaiensis, P. chesapeaki and P. marinus across continental and global spatial scales.

Main conclusions
Our results add further evidence of recent or continuous long-range dispersal and global connectivity for many haplotypes, suggesting that parasite dispersal through anthropogenic activities, such as maritime trade, likely contributes to these phylogeographic patterns.