Use of amplified fragment length polymorphism (AFLP) as a new tool to explore the invasive green alga Caulerpa taxifolia in Australia

Caulerpa taxifolia is a high profile introduced alga in the Mediterranean Sea and California. It is native to tropical and subtropical regions of Australia. However, during 2000/01, 7 locations with abundant C. taxifolia were discovered in temperate waters around Sydney. To overcome limitations of resolution in previous studies using ITS (internal transcribed spacer) rDNA sequencing, we developed amplified fragment length polymorphism (AFLP) markers for C. taxifolia, using 4 primer combinations. With this technique we found a close relationship between isolates from Moreton Bay (native) and Lake Conjola (introduced). The Mediterranean samples, which previously could not be separated from the other isolates, formed a discrete cluster supported by high bootstrap values. AFLP had greatly improved resolution over other molecular markers, making it a promising technique for further studies on the population structure of C. taxifolia and the assignment of source populations.