Karyotype characterization ofEpimediumspecies (Berberidaceae) by fluorescent banding and physical mapping of 45S and 5S rDNA

Abstract

Epimedium is a very important economic genus not only for medicinal usage but also for horticul- ture. We used combined PI-DAPI (CPD) staining techniques and fl uorescent in situ hybridization (FISH) with 5S and 45S rDNA probes to investigate the karyotypic and cytogenetic chracteristics of Epimedium species. All the tested species had the same chromosome number 2n=2x=12 and the same karyotype asymmetry type 2A. Just one pair of satellite chromosomes were found in each Epimedium species. Two different karyotype formulae were identifi ed in the tested eight species. The CPD banding patterns varied among the eight Epimedium spe- cies. In the double-target FISH analysis, the 45S rDNA probe revealed the loci closely to the secondary constric- tions of satellite chromosome pair and 5S rDNA were located on the short arms of one metacentric pairs in the specimens. The present results provide the basis for the molecular genetics in Epimedium.