Bdelloid Rotifers as a Model System for Investigating the Biology of Aging
We are employing rotifers of Class Bdelloidea, a group of small freshwater invertebrates, as a particularly advantageous model system for investigating the causes and control of aging — the progressive increase in death rate with age that occurs in adult humans and in other animals. Characteristics that make bdelloid rotifers a promising model system for such studies include: (i) parthenogenetic reproduction, assuring genetic homogeneity of progeny; (ii) very low or negligible death rate until egg deposition is completed, followed by an abrupt onset of aging manifested as an exponentially increasing (Gompertzian) death rate; (iii) extreme resistance of pre-aging bdelloids to ionizing radiation (IR) and IR-induced protein oxidation, allowing tests of the relation between aging and oxidative damage of a kind not possible in other organisms; (iv) completion of all somatic cell division before hatching, obviating replicative senescence as a possible complicating factor; (v) ease of culturing and production of even-age populations; (vi) normal mean life span of only a few weeks; (vii) transparency, allowing the use of fluorescence-based assays of reactive oxidative species (ROS) and oxidized protein on individual live animals; and (viii) a soon to be completed annotated genome sequence, allowing us to examine changes in specific gene expression accompanying the onset and progression of aging.
Homologous genetic exchange in bdelloid rotifers
Rotifers of Class Bdelloidea are common freshwater invertebrates whose ancient origin and apparent lack of sexual reproduction have posed the principal challenge to the generally held view that genetic transfer between individuals within a species is essential for its long-term evolutionary success. We have recently found, however, that bdelloid rotifers do engage in homologous genetic transfer within a species (or clade) and are attempting to characterize the mode of such exchange and the population structure within which it occurs.
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