两种水栖寡毛类染色体核型的研究  

THE KARYOTYPE OF LUMBRICULUS VARIEGATUS (MLLER) AND EISENIELLA TETRAEDRA TYPICA (SAVIGNY) (LUMBRICULIDAE,LUMBRICIDAE,OLIGOCHAETA)

作　　者：许智芳[1] 伯瑞克斯特RO 张德宁[1] 

机构地区：[1]南京大学生物系 [2]南京大学生物学系与加拿大海洋科学研究所

出　　处：《南京大学学报（自然科学版）》1990年第4期675-683,共9页Journal of Nanjing University（Natural Science）

摘　　要：本文对Omodeo(1951～1952、1955)和Vedovini(1973)等报道的正方拟爱胜蚓[Eiseniella tetraedra typica (Savigny)]的染色体数目进行了核实,对尚未见报道的夹杂带丝蚓[Lumbriculus variegalus(Moller)]染色体的核型进行了研究。夹杂带丝蚓2n=20。正方拟爱胜蚓的2n=12。在观察过程中还发现了在同一种内具有不同核型的个体,同时也发现在同一个体内具有染色体的多态现象。染色体的多态性是并存在个体内和个体间的,这种情况更有利于寡毛类动物去适应各种不同的环境,使它们得以更好地繁殖后代和延续它们的种族。Lumbriculus variegatus(MUller)was collected from Swan Lake Park and Eiseniella tetraedra typica(Savigny)was collected from Gold Stream in Victoria, B. C. respectively. They belong to two families, Lumbriculidae and Lumbricidae. They lived in different envi- ronments and their habits were different as well. This problem was responsive to their karyotype. Cytogenetics studies of the two species revealed the karyotype of L. variegatus as 2n=20, and E. tetraedra typica as 2n=12. The relative lengths of chromosome pairs in L. variegatus were 19.7985±1.4501, 15.4201±2.5440, 13.6201±1.0471, 11.4564±2.2824, 8.6498±2.2249, 7.4798±0.9753,6.7077±0.5105, 6.3682±0.6825, 5.6328±0.8831, and 4.8655±0.7658. In E. tetraedra typica, they were 22.4821±0.6788, 20.4551±0.7765, 18.6705±1.4980, 15.5905±1.5437, 12.7445±2.0092, and 10.0574±1.4984. All were telocentromere in L. variegatus and E. tetraedra typica. In hermaphroditic oligochaetes polyploidy appeared to be more frequent. Amony the organisms, 40% of the investigated karyotypes(about 250)had been found to be polyploid(Casellato, 1987). Our observation also found the polymorphism of chromosomes in two oligochaetes. In the study, we found the different karyotype individuals in a species and the chromosome polymorphism in a specimen. From this, we could deduce that chromosome polyploidy coexists in a individual and between individuals. This fact would provide them with favourable qualities for life, the ability to resist environmental stresses, to reproduce future generations, and to continue their race. Mihailova and Subchev(1981)considered that the chromosome polymorphism was due to the mosiac occurence caused by the missing of translocation of chromosomes. Evi-dently, this paper was reliable, because we discovered not only sub-ploid, but also super-ploid, though we did not find any translocation rings. Using different times and comcentrations of colchicine for L. variegatus and E. tetraedra typica, we treated the former with a higher concentration(400μl/30ml)

关 键 词：寡毛类 染色体 核型 多倍体 

分 类 号：Q959.193[生物学—动物学]