Nuclear rDNA characteristics for DNA taxonomy of the centric diatom Chaetoceros (Bacillariophyceae)

doi:2010.25.2.65

Algae > Volume 25(2); 2010 > Article

Algae 2010;25(2): 65-70. doi: https://doi.org/10.4490/algae.2010.25.2.065

Hye-Young Oh¹, Ju-Yong Cheon¹, Jin Hwan Lee¹, Sung Bum Hur² and Jang-Seu Ki¹^,*

¹Department of Green Life Science, Sangmyung University, Seoul 110-743, Korea,
²Korea Marine Microalgae Culture Center, Department of Aquaculture, Pukyong National University, Busan 608-737, Korea

ABSTRACT

The genus Chaetoceros provides highly diversified diatoms in marine systems. Morphological descriptions of the genus are well-documented, yet the DNA taxonomy of Chaetoceros has not been satisfactorily established. Here, the molecular divergences of the 18S-28S rDNA of Chaetoceros were assessed. DNA similarities were relatively low in both 18S (93.1 ± 3.9%) and 28S rDNA (81.0 ± 4.6%). Phylogenies of the 18S, 28S rDNAs showed that Chaetoceros was divided according to individual species, clustering the same species into single clades. Statistical analysis with corrected genetic (p-) distance scores showed that nucleotide divergence of Chaetoceros 28S rDNA significantly differed from that of 18S rDNA (Student’s t-test, p < 0.05). This finding suggests that the 28S rDNA may be treated as a more suitable marker for species-level taxonomic distinctions of Chaetoceros.

Key words: Chaetoceros; DNA taxonomy; marine diatom; nucleotide divergence; ribosomal DNA