We propose a novel way of modelling time-varying networks by inducing two-way sparsity on local models of node connectivity. This two-way sparsity separately promotes sparsity across time and sparsity across variables (within time). Separation of these two types of sparsity is achieved through a novel prior structure which draws on ideas from the Bayesian lasso and from copula modelling. We provide an efficient implementation of the proposed model via a Gibbs sampler, and we apply the model to data from neural development. In doing so, we demonstrate that the proposed model is able to identify changes in genomic network structure that match current biological knowledge. Such changes in genomic network structure can then be used by neurobiologists to identify potential targets for further experimental investigation.
The work of the first author was supported by the MRC grant MR/P014070/1. The work of the second and third authors was partially supported by The Alan Turing Institute under the EPSRC grant EP/N510129/1.
We are grateful to Aaron Diaz, Tom Nowakowski, Alex Pollen and Aparna Bhaduri for helpful discussions, insightful comments and useful advice throughout this project and for providing early access to the data.
"Two-way sparsity for time-varying networks with applications in genomics." Ann. Appl. Stat. 15 (2) 856 - 879, June 2021. https://doi.org/10.1214/20-AOAS1416