UBC Undergraduate Research

Modeling macronuclear DNA regulation in two ciliates : Paramecium tetraurelia and Tetrahymena thermophila Elphinstone, Cassandra; Cheadle, Kyle


A revision to existing models for regulating the macronuclear DNA content of the ciliates Paramecium tetraurelia and Tetrahymena thermophila explains previously unresolved observations. Using an independent parameter to regulate ciliate macronuclear DNA content allows the mass of P. tetraurelia to be linked with DNA regulation. A similar parameterization of the T. thermophila model accounts for observed generation-dependent variations. Introducing controlled selection rules on macronuclear DNA content in modeled populations of T. thermophila results in evolving periodic distributions. The amount of unequal macronuclear division in the population is then directly proportional to the frequency of the resulting oscillation. Unequal division acts to restore the distribution opposing the selection displacement. Another parameter related to the replication’s independence from macronucleus DNA content shows a critical value of the √2–1 such that higher values result in periodic variations while lower values do not.

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