Study And Location Of Telomere-associated Sequences And 5SrDNA On Chromosomes Of Cunninghamia Lanceolata

In the study, two telomere-associated sequences, TAS1 and TAS2 were isolated from Cunninghamia Lanceolata. The 5S rDNA gene sequences of Taxodium mucronatum,T. ascendens.Brongn,T. distichum,T.distichum×T. mucronatum,T. mucronatum×Cryptomeria fortunei were cloned and sequenced, then compared with other plants. It was the first time to localize the TAS1 and 5S rDNA on Chromosomes of Cunninghamia Lanceolata by FISH (Fluorescence in situ hybridization).Two telomere-associated sequences, TAS1 and TAS2 were isolated from Cunninghamia Lanceolata by single-primed PCR, and compared with the sequences in the NCBI, It presumed that TAS1 and TAS2 might come from different chromosomes of Cunninghamia Lanceolata. It conclusioned that even the same species, the same individual, it was low homology and high polymorphic between TAS DNA sequences.It was cloned and sequenced 5S rDNA of T.mucronatum,T. ascendens.Brongn,T.distichum,T.distichum×T. mucronatum,T.mucronatum×C.fortunei, then compared with C. Lanceolata,C. fortunei and M.glyptostroboides. It was found that C.Lanceolata had low similarity with T. distichum×T. mucronatum,T. mucronatum×C. fortunei,T. distichum,M. glyptostroboides,T. ascendens.Brongn, lower with C. fortunei and T. mucronatum, while C. fortunei had the lowest similarity, had the farthest relationship with other six species. Our results illustrated that there were large variation of 5S rDNA gene. The similarity of 5S rDNA gene region of T. mucronatum×C. fortunei with T. mucronatum was 99.2%, with C. fortunei was 84.9%, It speculated that it was a concerted evolution phenomenon. The similarity of 5S rDNA gene region of T. distichum×T. mucronatum,M. glyptostroboides and T. ascendens.Brongn was 100%, It presumed that the 5S rDNA gene of T. distichum×T. mucronatu,M. glyptostroboides and T. ascendens.Brongn have completely concerted evolution.It was the first time to localize the TAS1 on metaphase chromosome of Cunninghamia Lanceolata by FISH, the results indicated that there were four cross loci. It was localized 5S rDNA which used as a probe on mitotic chromosomes of Cunninghamia Lanceolata, the results indicated that there were two cross signal which had been detected both in the nucleus and metaphase chromosomes.