Nucleotide sequence variation was unexpectedly low in an endangered species, Aldrovanda vesiculosa L. (Droseraceae)

Using fluorescence in situ hybridization (FISH) and polymerase chain reaction direct sequence methods, 45S ribosomal DNA (rDNA) loci on somatic chromosomes were detected and partial sequence of 45S rDNA was determined in Aldrovanda vesiculosa, respectively. Analysis of FISH showed tree to five 45S rDNA signals in interphase nuclei, and four signals at metephase stage. All FISH signals at metaphase stage were located at the terminal region of four chromosomes. Among six populations, completely homologue sequence result was supplied from Clustal W analysis. After determining sequences of 5.8S and internal transcribed spacer (ITS) in 45S rDNA of six populations, a comparative study with these sequences was carried out to infer genetic diversity in A. vesiculosa.