Geron等通过遗传工程使细胞表达端粒酶(telomerase),延长了正常人的包皮纤维母细胞及视网膜色素上皮细胞的寿命。端粒酶是保护染色体终端的一种酶,而端粒(telomeres)在细胞分裂时脱失。尽管大部分研究者对开展端粒酶研究工作可使人类寿命延长的设想有怀疑,但认为有可能开创成为老年病及癌症的新疗法。在正常体细胞中,细胞于每次分裂时染色体有缩短,因在每次细胞分裂及DNA复制时约 Geron and other genetically engineered cells to express telomerase (telomerase), extending the life of normal human foreskin fibroblasts and retinal pigment epithelial cells. Telomerase is an enzyme that protects the end of the chromosome, and telomeres are lost during cell division. Although most researchers are suspicious of the idea that telomerase research may extend human life expectancy, it is believed that it is possible to create new treatments for geriatric diseases and cancers. In normal somatic cells, the chromosomes are shortened at each division, because at every cell division and DNA replication