Assessment of the genetic connectivity between farmed and wild populations of Undaria pinnatifida (Phaeophyceae) in a representative traditional farming region of China by using newly developed microsatellite markers
Undaria pinnatifida is an important economic macroalga extensively farmed in East Asia. Wild individuals of U. pinnatifida, which can be easily discriminated due to their peculiar morphology, are usually observed to occur on the cultivation infrastructure adjacent to the farmed ones in the farming area. The genetic connectivity between the wild and farmed populations, however, remains unidentified. In this study, 30 informative microsatellite markers were developed and characterized through the next-generation sequencing technology. Ten of them were used to analyze the genetic structure of wild and farmed populations sampled from a representative Undaria farm in Lüshun (latitude: 38° 47′ N) from 2015 to 2017, with two wild populations from Qingdao (36° 03′ N) and Gouqi Island (30° 42′ N) as controls. The dendrogram clearly separated farmed populations from wild ones by large genetic distance. The Bayesian model-based structure analysis grouped all the populations into five clusters. The wild individuals on the farm were found to contain relatively a large proportion of membership originated from farmed ones. In contrast, nearly no wild membership was detected in the farmed populations. These results imply asymmetric gene flow between farmed and wild populations and indicate that the pedigree of farmed cultivars has been well maintained through artificial control in the current seedling production system. Efforts should be made to popularize this system for the benefits of sustainable utilization of cultivars in Undaria farming.
KeywordsUndaria pinnatifida Kelp Genetic structure Microsatellite Seaweed cultivation
The authors would like to thank Mingfu Zhang and Hongtao Gao for their help in sample collection.
This research was supported by grants of the National Natural Science Foundation of China (No. 41676128 and 41476141), the Sino-German Science Center (GZ 1080), China Agriculture Research System (CARS-50), National Key Technology Support Program (2015BAD13B05), the National Infrastructure of Fishery Germplasm Resource (2017DKA30470), the Taishan Scholar Program of Shandong Province, and Huiquan Scholar Program of Institute of Oceanology, Chinese Academy of Sciences.
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