Phylogeny of Cucurbita Based on ITS sequence data

The relationships and differences among the species,Cucurbita,pepo and ficifofia (Cucurbitaceae:Cucurbita),were examined using data from the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. The ITS sequences were obtained from Cucurbita,pepo and ficifofia 3 species. The results showed that,within Cucurbita,ITS1 was 188-191bp (C. Cucurbita,C. pepo and C. ficifofia) and ITS2 ranged from 251-263bp (C. Cucurbita,C. pepo and C. ficifofia). There were 33 variable positions (17.55%) and 24 informative sites (12.77%) within Cucurbita found in the ITS1 sequences,while 45 variable positions (17.93%) and 31 informative sites (12.35%) found in the ITS2 sequences.The G+C content of ITS1 was 51.60% to 54.50% and that of ITS2 ranged from 53.78% to 56.98%.The resulting trees from the ITS1 and ITS2 sequences showed that the relationship between C. Cucurbita and C. pepo was closer than that between C. Cucurbita and C. ficifofia.