at present, researchers are only just beginning to understand the biological basis of aging even in relatively simple and short-lived organisms such as yeast. less still is known of mammalian aging, in part due to the much longer lives of even small mammals such as the mouse (around 3 years). a model organism for studying of aging is the nematode "c. elegans". thanks to its short lifespan of 2–3 weeks, our ability to easily perform genetic manipulations or to suppress gene activity with rna interference, or other factors. most known mutations and rna interference targets that extend lifespan were first discovered in "c. elegans".