  We use a mesoscale simulation approach to explore the impact of different
capsid geometries on the packaging and ejection dynamics of polymers of
different flexibility. We find that both packing and ejection times are faster
for flexible polymers. For such polymers a sphere packs more quickly and ejects
more slowly than an ellipsoid. For semiflexible polymers, however, the case
relevant to DNA, a sphere both packs and ejects more easily. We interpret our
results by considering both the thermodynamics and the relaxational dynamics of
the polymers. The predictions could be tested with bio-mimetic experiments with
synthetic polymers inside artificial vesicles. Our results suggest that phages
may have evolved to be roughly spherical in shape to optimise the speed of
genome ejection, which is the first stage in infection.
