1. A method for constructing a model of a biological pathway comprising a plurality of genes, the method comprising: (A) obtaining an eQTL vector for a gene X in said plurality of genes; (B) obtaining an eQTL vector for a gene Y in said plurality of genes; (C) constructing a prior p(X→Y) that represents a probability that said gene X is upstream of said gene Y in said biological pathway, wherein p ⁡ ( X -> Y ) = r ⁡ ( X , Y ) ⁢ N ⁡ ( Y ) N ⁡ ( X ) + N ⁡ ( Y ) , wherein N(Y) is a number of eQTL in the eQTL vector for said gene Y; N(X) is a number of eQTL in the eQTL vector for said gene X; and r(X,Y) is a weight that represents a correlation between the eQTL vector for said gene X and the eQTL vector for said gene Y; and (D) computing said model of said biological pathway using Bayesian analysis that incorporates the prior p(X→Y) constructed in step (C), wherein said computing step is carried out on a suitably programmed computer.