MS2a, Week 6, Model Solution

Consider the network from [1, Fig. 3b]: A B a. Assume the network grows as described in [1, Fig. 3b], by duplication of a gene (node) chosen uniformly at random. For the nodes marked A and B, respectively, compute the expected number of connections a random descendant has after a single duplication step, i.e. when the network has grown to seven nodes. The three possible topologies we can have after the update are 1 6 1 6 1 6 1 3 1 6