CAJ | 학술논문

测定了角叉菜属(Chondrus)5个代表种的核糖体DNA内转录间隔区(ITS)及5.8S rDNA基因序列.结果表明,角叉菜属ITS区(含ITS1、5.8S rDNA和ITS2)序列长度范围为704-714bp,G+C含量为44.6%-45.7%,变异位点69个,信息位点16个;其中,ITS1和ITS2的长度范围分别为147-149bp和398-404bp.5.8S rDNA长度为158bp,没有变异和信息位点.由MEGA3构建的系统进化树(ME和MP)显示:在进化尺度上,真红藻纲的松节藻科(Rhodomelaceae)与红毛菜纲(Bangiophyceae)亲缘关系较近.在真红藻纲内,杉藻目(Gigartinales)进化地位相对较高,其次是海膜科(Halymeniaceae)、石花菜科(Gelidiaceae)、红叶藻科(Delesseriaceae)和粉枝藻科(Liagoraceae)等,而松节藻科进化地位相对较低.在杉藻目内,杉藻科(Gigartinaceae)和胶黏藻科(Dumontiaceae)进化关系密切,而形态学特征相似的角叉菜和马泽藻(Mazzaella)亲缘关系非常近.
측정료각차채속(Chondrus)5개대표충적핵당체DNA내전록간격구(ITS)급5.8S rDNA기인서렬.결과표명,각차채속ITS구(함ITS1、5.8S rDNA화ITS2)서렬장도범위위704-714bp,G+C함량위44.6%-45.7%,변이위점69개,신식위점16개;기중,ITS1화ITS2적장도범위분별위147-149bp화398-404bp.5.8S rDNA장도위158bp,몰유변이화신식위점.유MEGA3구건적계통진화수(ME화MP)현시:재진화척도상,진홍조강적송절조과(Rhodomelaceae)여홍모채강(Bangiophyceae)친연관계교근.재진홍조강내,삼조목(Gigartinales)진화지위상대교고,기차시해막과(Halymeniaceae)、석화채과(Gelidiaceae)、홍협조과(Delesseriaceae)화분지조과(Liagoraceae)등,이송절조과진화지위상대교저.재삼조목내,삼조과(Gigartinaceae)화효점조과(Dumontiaceae)진화관계밀절,이형태학특정상사적각차채화마택조(Mazzaella)친연관계비상근.
Chondrus Stackhouse is a perennial red seaweed with alternate phases of gametophyte and tetrasporophyte; over-harvesting and environmental pollution have hugely reduced the population resource and resulted in shortage of a constant and reliable supply. For this genus.the classification and systematics are puzzled for variable forms, habitats and phenotypic plasticity. Meanwhile, as a representative family in Rhodophyta, Gigartinaceae are one of the important taxa for understanding the origin and evolution of red algae because of its lower position in cladograms of Rhodophyta phylogeny based on molecular data. However, both the phylogenetic affinity within Gigartinales and the evolution status of Gigarti-naceae in Rhodophyta remain uncertain. In this study, the internal transcribed spacer (ITS) region of nuclear ribosomal DNA and 5.8S rDNA gene were sequenced for five representative species of Chondrus, C. ocellatus, C. armatus, C. yendoi, C. pinnulatus and C. crispus, for assessing the phylogenetic relationships in Rhodophyta on molecular level, in addition to reevaluation of the evolutionary status of Chondrus. The results indicate that the ITS region ranges from 704 to 714bp and G+C content varies from 44.6% to 45.7%, including 69 variable sites and 16 informative sites; and the length variation is 1.4%. ITS1 (147-149bp) with 16 variable sites and four informative sites is shorter than ITS2 (398-404bp) with 53 variable sites and 12 informative sites; and 5.8S rDNA gene has conservative 158bp, with no variable and informative sites. Phylogenetic analyses using minimum-evolution and maximum-parsimony methods with MEGA3 show that Rhodome- laceae in Florideophyceae is closely related to Bangiophyceae at evolutional level. In Florideophyceae, Gigartinales has the relatively highest evolutional level, then Halymeniaceae, Gelidiaceae, Delesseriaceae and Liagoraceae, and Rhodome-laceae the lowest. In Gigartinales, Gigartinaceae and Dumontiaceae have a close relationship, while Chondrus and Maz-zaella, which are difficult to discriminate in morphology, formed a fairly compact clade. The low divergence among Chondrus species is justified considering its more recent origin, and also suggests that ITS sequence would provide a promising method for molecular phylogenetic analysis, and to reconstruct the phylogeny within Rhodophyta on order and family levels.