Isolation of longevity related genes of prasitic nematodes with east epression system

与相关的自由生活物种相比，寄生动物活得更长。为了阐明长寿的分子基础，我们构建了一种肠道线虫的高质量的基因组草稿，用生物信息学来探讨这一问题。我们的基因组初稿统计如下：总大小55.5Mb，最长支架15Mb，N50支架长度2Mb，预测编码基因18,048个。其中一个基因只存在于寄生线虫中，而不存在于自由生活的线虫中，其中一个基因是铁络合酶基因，它催化HEM生物合成的最后一步。我们证实，尽管包括动物寄生线虫在内的所有线虫都不会自行合成HEM，但该基因是完全有功能的。系统发育分析表明，动物寄生线虫是通过水平基因转移从细菌获得该基因的。它的生理作用可能是解毒，因为它对细胞有很高的毒性。

Parasitic animals live longer as compared with related free-living species. In order to elucidate molecular basis for the longevity, we constructed a high-quality draft genome of an intestinal nematode, Strongyloides venezuelensis, to approach this issue with bioinformatics. Statistics of our draft genome were as follows; total size 55.5 Mb, longest scaffold 15Mb, N50 scaffold length 2Mb, with 18,048 predicted coding genes.One of the genes which exist only in parasitic nematodes but not in free-living nematodes was that for ferrochelatase, which catalyzes the final step of hem-biosynthesis. We confirmed that this gene of S. venezuelensis was perfectly functional, though all nematodes including animal parasitic nematodes do not synthesize hem by themselves. Phylogenetic analysis suggested that animal parasitic nematodes acquired this gene from bacteria through horizontal gene transfer. The physiological role could be to detoxify hem, which is highly toxic to cells.