Studies on the genetic effect in termite caste determination

1. 白蚁的孤雌生殖能力和孤雌生殖者的等级比：研究了6种白蚁（4种网白蚁、neadensis白蚁、koshunensis白蚁）和不同区域种群的孤雌生殖能力。原性种不能通过孤雌生殖进行生殖，但各地方种群的个体均能进行生殖。所有的孤雌生殖都发育成雌性若虫。通过线粒体基因的分子系统发育分析，推测了当地种群的系统发育。遗传等级决定模型的检验：以日本甘山田鼠和冲绳田鼠为研究对象，对遗传等级终止模型进行了检验。采用雌雄若虫和拟人幼生殖体进行了四种类型的杂交实验。卵由雄性工蜂饲养。在前一种物种中，后代的种姓/性别比例与遗传模型的期望值没有差异。在白蚁属中也得到了几乎相同的结果，说明白蚁属的等级比例有一个共同的调节机制。寻找种姓和性别的遗传标记：我们进行了AFLP分析，以寻找种姓或性别特定的遗传标记。利用21对选择性引物，共发现316个AFLP多态性位点，但未发现种姓特异性条带。然而，发现了一个男性特有的AFLP位点，可能在y染色体上。我们还建立了脉冲场凝胶电泳分离性染色体的实验条件。田间群体遗传结构和等级比：利用微卫星标记和mt-DSCP标记对茨城县东海地区的褐家鼠遗传结构进行了研究。我们估计了殖民地的边界，并检查了田野殖民地的种姓组成。

1. Parthenogenetic ability of termites and caste ratio of the parthenogens:Six species of termites (four Reticulitermes spp., Z. nevadensis, N. koshunensis) and regional populations of R. speratus were investigated on their parthenogenetic ability. The former sex species could not reproduce by parthenogenesis, but individuals from every local population of R. speratus could. All the parthenogens developed into female nymphs. The phylogeny of the local populations of R. speratus was inferred by molecular phylogenetic analysis of mitochondrial genes.2. Test of genetic caste determination model:Using R. kanmonensis and R. okinawanus, the genetic caste getermination model was tested. We carried out four types of crossing experiments using male and female nymphoid and ergatoid neotenic reproductives. Eggs were reared by male workers. In the former species the realized caste/sex ratios of the offspring did not differ from the expected values of the genetic model. The almost the same results were obtained in R. okinawanus, suggesting that a common mechanism regulate the caste ratio in the genus Reticulitermes.3. Search for the caste-and sex-lined genetic markers:We carried out AFLP analysis to find caste or sex specific genetic markers. Using 21 selective primer pairs, we found 316 polymorphic AFLP loci, but could not find caste specific bands. However, one male specific AFLP locus was found, which probably on the Y-chromosome. We also set up the experimental conditions of pulsed-field gel electrophoresis to separate sex chromosomes.4. Genetic structure and caste ratio in the field colony:We investigated of the genetic structures of R. speratus in Tokai, Ibaraki pref. using microsatellite and mt-DSCP markers. We estimated colony boundaries and examined caste compositions of the field colonies.