DAO 103:65-75 (2013)  -  DOI: https://doi.org/10.3354/dao02559

Conservation in the first internal transcribed spacer (ITS1) region of Hematodinium perezi (genotype III) from Callinectes sapidus 

Katrina M. Pagenkopp Lohan1,3, Hamish J. Small1, Jeffrey D. Shields1, Allen R. Place2, Kimberly S. Reece1,*

1Virginia Institute of Marine Science, The College of William & Mary, Gloucester Point, Virginia 23062, USA
2Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA
3Present address: Smithsonian Conservation Biology Institute, Center for Conservation and Evolutionary Genetics, National Zoological Park, Washington, DC 20008, USA
*Corresponding author. Email:

ABSTRACT: Hematodinium spp. infections have been reported from blue crabs Callinectes sapidus in high-salinity waters of the USA from New Jersey to Texas. Recently, H. perezi (genotype III) has been proposed as the parasite species and genotype infecting blue crabs from Virginia; however, it is unknown whether this same genotype is present in blue crabs from other locations. To address this question, we collected 317 blue crabs from Massachusetts, Virginia, Georgia, Florida, Louisiana, and Texas to test for the presence of H. perezi (III) using a specific PCR assay targeting the first internal transcribed spacer (ITS1) region of the ribosomal RNA gene complex. To examine the genetic variation within H. perezi (III), ITS1 region sequences from the parasite in blue crabs from multiple locations were compared to each other and to those of H. perezi (III) found in alternate hosts from Virginia. In total, 34 distinct ITS1 sequence variants of the parasite were identified from blue crabs alone, and 38 distinct variants were identified when alternate hosts were included. However, a single ITS1 sequence variant appeared in all geographic regions and hosts, and also in blue crabs sampled from a previous study. The high similarity among all the ITS1 region sequences examined (>98%) and the observation of a single variant found throughout a large geographic range, strongly suggests that a single species and genotype of Hematodinium, specifically H. perezi (III), infects blue crabs from Virginia to Texas and multiple alternate host species in Virginia.


KEY WORDS: Dinoflagellate · Parasite · Blue crab · Crustacean · ITS1 region · Alternate hosts · Genetic variation


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Cite this article as: Pagenkopp Lohan KM, Small HJ, Shields JD, Place AR, Reece KS (2013) Conservation in the first internal transcribed spacer (ITS1) region of Hematodinium perezi (genotype III) from Callinectes sapidus . Dis Aquat Org 103:65-75. https://doi.org/10.3354/dao02559

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