Recent advances in biotechnology allow researchers to measure expression le
vels for thousands of genes simultaneously, across different conditions and
over time. Analysis of data produced by such experiments offers potential
insight into gene function and regulatory mechanisms. A key step in the ana
lysis of gene expression data is the detection of groups of genes that mani
fest similar expression patterns. The corresponding algorithmic problem is
to cluster multicondition gene expression patterns, In this paper we descri
be a novel clustering algorithm that was developed for analysis of gene exp
ression data. We define an appropriate stochastic error model on the input,
and prove that under the conditions of the model, the algorithm recovers t
he duster structure with high probability, The running time of the algorith
m on an n-gene dataset is O{n(2)[log(n)](c)}. We also present a practical h
euristic based on the same algorithmic ideas. The heuristic was implemented
and its performance is demonstrated on simulated data and on real gene exp
ression data, with very promising results.