Study Of Karyotype Of Cunninghamia Lanceolata.Var.Duganshan And 5SrRNA Gene Of Cunninghamia Lanceolata

Karyotype formula of Cunninghamia Lanceolata var. Duganshan was established using karyotype analysis and a preliminary comparison between Cunninghamia Lanceolata and Duganshan. 5S ribosomal RNA gene sequences of Cunninghamia Lanceolata, Taxodium distichum, Cryptomeria japonica and Metasequoia glyptostroboides were cloned and sequenced, then the primary and the secondary structures of 5SrRNA gene of Taxodiaceae were comparatived with other gymnosperms. The study tried to use fluorescence in situ hybridization studying chromosome of Cunninghamia Lanceolata.The karyotype formula of Duganshan was 2n = 22= 2sm +20m (2sat), which was the same to Cunninghamia Lanceolata.There were 10 pairs of the central centromere chromosome and one pair of near the middle centromere chromosome in the both plants. The arm ratio of near the middle centromere chromosome of Cunninghamia Lanceolata was larger than that in Duganshan. And their location in the chromosomal group was not the same site, which could be the result from chromosome structural variation.Compared 5SrRNA genes of Taxodiaceae with other gymnosperms plants, there were larger variation, the most variation in the spacer. The paper result was not the same to that 5S rRNA gene was highly conservatived structure considered by the traditional view.5SrRNA genes of Cunninghamia Lanceolata, Taxodium distichum, Cryptomeria japonica and Metasequoia glyptostroboides had low level of the similarity. There were large genetic variation of 5SrDNA among four species during their evolution. The length of 5SrRNA gene duplication units of Metasequoia glyptostroboides was longer than the other most gymnosperms. 5SrRNA gene of Cryptomeria japonica was the largest variation in the four Taxodiaceae species. The secondary structure of 5SrRNA gene of the four species was similer to the other gymnosperms. Some variable locations show fixed bases in loop regions and stem regions, especially sequences in stem regionsâ… of 5 'chain, almost all of stem regionsâ…£, and all the loop regions. But there were variations characteristics of theirseves in the other stem regions.