Taguchi T, Hirai H, Upatham S, Agatsuma T
Department of Anatomy, Kochi Medical School, Nankoku 783-8505, Japan.
Parasitol Int. 2000 Dec;49(4):267-72. doi: 10.1016/s1383-5769(00)00053-2.
Chromosome analyses were performed on three races (alpha, beta, gamma) of Neotricula aperta which were previously reported to show variation in the chromosome number and pairing in meiosis. We used an air-drying method, which was more reliable for chromosome preparations from fresh animal tissues than a squash method. Each of the races had the same number of chromosomes, 2n=33 for males, and 2n=34 for females. The sex determination system was XO type (male: 32+X, female: 32+XX). The sex chromosome of each race was distinct in its morphology, but not in its length. Karyotyping revealed that the X-chromosome of the alpha race was metacentric (M), whereas it was acrocentric (A) in the beta and the gamma races. An association between the X-chromosome and a small autosome in meiosis suggested that a neo-Y chromosome probably lies in the terminal region of the small autosome.
对之前报道减数分裂中染色体数目和配对存在变异的三种新小杆线虫（α、β、γ）品系进行了染色体分析。我们采用了空气干燥法，相较于压片法，该方法从新鲜动物组织制备染色体标本更为可靠。每个品系的染色体数目相同，雄性为2n = 33，雌性为2n = 34。性别决定系统为XO型（雄性：32 + X，雌性：32 + XX）。每个品系的性染色体形态各异，但长度相同。核型分析显示，α品系的X染色体为中着丝粒染色体（M），而β和γ品系的为近端着丝粒染色体（A）。减数分裂中X染色体与一条小常染色体之间的关联表明，新Y染色体可能位于这条小常染色体的末端区域。
