  Long ago, life obtained nucleotides in the course of evolution and became a
vehicle for them. Before assembly with nucleotides, in the pre-RNA era, what
system dominated heredity? What was the subject of survival competition? Is it
still a subject of competition? Self-organized complex systems are hypothesized
to be a primary factor of the origin of life and to dominate heritability,
mediating the partitioning of an equal distribution of structures and molecules
at cell division. The degree of strength of self-organization would correlate
with heritability; self-organization is known to be a physical basis of
hysteresis phenomena, and the degree of hysteresis is quantifiable. However,
there is no argument corroborating the relationship between heritability and
hysteresis. Here, we show that the degree of cellular hysteresis indicates its
heritability and daughter equivalence at cell division. We found a correlation
between thermal hysteresis in cell size and heritability, which quantified cell
line generation stability, suggesting that the self-organized complex system is
a subject of survival competition, comparable to nucleotides. Furthermore, in
single-cell-resolution observations, we found that thermal hysteresis in cell
size indicates equivalent partitioning in future cell division. Our results
demonstrate that self-organized complex systems contribute to heredity and are
still important in mammalian cells. Predicting the cell line generational
stability required for the industrial production of therapeutic biologics is
useful. Discovering ancient and hidden heredity systems enables us to study our
own origin, to predict cell features and to manage them in the bio-economy.
