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Internal Transcribed Spacer Polymorphism in Pseudo-nitzschia multistriata (Bacillariophyceae) in the Gulf of Naples: Recent Divergence or Intraspecific Hybridization?
- Source :
- Protist. 160:9-20
- Publication Year :
- 2009
- Publisher :
- Elsevier BV, 2009.
-
Abstract
- The planktonic diatom Pseudo-nitzschia multistriata is a potentially toxic species recorded during late summer–autumn in the Gulf of Naples (Tyrrhenian Sea, Italy). We analysed the genetic structure by amplifying the internal transcribed spacer (ITS-1–5.8S–ITS-2) region of the ribosomal DNA of 44 strains isolated along 2 years. Polymorphism in the ITS region was detected by direct sequencing and the PCR-products from selected strains were thus cloned to assess intra-strain ITS variability. Strains clustered into three main types: type A and B – differing by 0.6% sequence divergence – and type A/B, showing both A and B variants within the same genome. The three types showed no differences in the large subunit sequences (LSU) of the rDNA, ultrastructure of the valve, secondary structure of ITS-1 and ITS-2, ploidy level and they were sexually compatible. Based on the results of these multiple approaches, we can state that the three ITS-types belong to the same reproductive unit (or “species” sensu Mayr [(1942). Systematics and the Origin of Species. Columbia University Press, New York]). We suggest that ITS polymorphism in P. multistriata may be related to the contemporary occurrence of different but still inbreeding populations which either diverged recently or originated in different geographic areas and became sympatric in the studied area.
- Subjects :
- 0106 biological sciences
Systematics
Zoology
01 natural sciences
Microbiology
Evolution, Molecular
03 medical and health sciences
DNA, Algal
Species Specificity
Sensu
DNA, Ribosomal Spacer
14. Life underwater
Internal transcribed spacer
Ribosomal DNA
030304 developmental biology
Diatoms
Genetics
0303 health sciences
Genetic diversity
Ploidies
Polymorphism, Genetic
biology
010604 marine biology & hydrobiology
Sequence Analysis, DNA
biology.organism_classification
Genetics, Population
Italy
Sympatric speciation
Genetic structure
Hybridization, Genetic
Nucleic Acid Conformation
Pseudo-nitzschia
Subjects
Details
- ISSN :
- 14344610
- Volume :
- 160
- Database :
- OpenAIRE
- Journal :
- Protist
- Accession number :
- edsair.doi.dedup.....a4a710f6c210b24fe5ceaa3fda3b0ed9