Genetic variability and potential sources of Grateloupia doryphora (Halymeniaceae, Rhodophyta), an invasive species in Rhode Island waters (USA)

Document Type

Article

Publication Title

Journal of Phycology

Publication Date

8-1-2002

Abstract

Grateloupia doryphora (Montagne) M. Howe is an invasive foliose alga that was reported for the first time in Rhode Island, USA in 1997. The population has since increased in size and expanded in range. In this study, the genetic variation and potential sources of the Rhode Island G. doryphora population were examined using three types of molecular markers: randomly amplified polymorphic DNA (RAPD), nuclear internal transcribed spacer (ITS) sequences, and mitochondrial cox2-cox3 intergenic spacer (COX) sequences. No variation was detected in ITS or COX sequences among Rhode Island G. doryphora individuals. RAPDs, however, did reveal genetic variation, although banding patterns were similar, with RAPD genetic distances between individuals ranging from 0.00 to 0.17. The low level of genetic diversity observed within the Rhode Island population may be due to a small founder population or a founder population derived from a genetically uniform source. To identify possible sources of the Rhode Island invasion, individuals from nine geographically diverse populations of foliose Grateloupia were compared. Phylogenetic trees inferred from RAPD distances and ITS and COX sequences had similar topologies; thus there was phylogenetic congruence among these independent loci. The Rhode Island G. doryphora specimens were genetically similar to specimens from G. doryphora populations located in Portsmouth, England; Tholen Island, The Netherlands; and Brittany and Hérault, France. Interestingly, the G. doryphora population in each of these locations is itself due to an introduction event within the past 40 years.

Volume

38

Issue

4

First Page

649

Last Page

658

DOI

10.1046/j.1529-8817.2002.01063.x

ISSN

00223646

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