Correcting the loss of cell-cycle synchrony in clustering analysis of microarray data using weights

  • Authors:
  • Fenghai Duan;Heping Zhang

  • Affiliations:
  • Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA;Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA

  • Venue:
  • Bioinformatics
  • Year:
  • 2004

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Abstract

Motivation: Due to the existence of the loss of synchrony in cell-cycle data sets, standard clustering methods (e.g. k-means), which group open reading frames (ORFs) based on similar expression levels, are deficient unless the temporal pattern of the expression levels of the ORFs is taken into account. Methods: We propose to improve the performance of the k-means method by assigning a decreasing weight on its variable level and evaluating the 'weighted k-means' on a yeast cell-cycle data set. Protein complexes from a public website are used as biological benchmarks. To compare the k-means clusters with the structures of the protein complexes, we measure the agreement between these two ways of clustering via the adjusted Rand index. Results: Our results show the time-decreasing weight function---exp[-(1/2)(t2/C2)---]which we assign to the variable level of k-means, generally increases the agreement between protein complexes and k-means clusters when C is near the length of two cell cycles.