  We study sharp peak landscapes (SPL) of Eigen model from a new perspective
about how the quasispecies distribute in the sequence space. To analyze the
distribution more carefully, we bring forth two tools. One tool is the variance
of Hamming distance of the sequences at a given generation. It not only offers
us a different avenue for accurately locating the error threshold and
illustrates how the configuration of the distribution varies with copying
fidelity $q$ in the sequence space, but also divides the copying fidelity into
three distinct regimes. The other tool is the similarity network of a certain
Hamming distance $d_{0}$, by which we can get a visual and in-depth result
about how the sequences distribute. We find that there are several local optima
around the center (global optimum) in the distribution of the sequences
reproduced near the threshold. Furthermore, it is interesting that the
distribution of clustering coefficient $C(k)$ follows lognormal distribution
and the curve of clustering coefficient $C$ of the network versus $d_{0}$
appears as linear behavior near the threshold.
