Probabilistic Clustering of Sequences: Inferring new bacterial regulons by comparative genomics

Genome wide comparisons between enteric bacteria yield large sets of conserved putative regulatory sites on a gene by gene basis that need to be clustered into regulons. Using the assumption that regulatory sites can be represented as samples from weight matrices we derive a unique probability distribution for assignments of sites into clusters. Our algorithm, 'PROCSE' (probabilistic clustering of sequences), uses Monte-Carlo sampling of this distribution to partition and align thousands of short DNA sequences into clusters. The algorithm internally determines the number of clusters from the data, and assigns significance to the resulting clusters. We place theoretical limits on the ability of any algorithm to correctly cluster sequences drawn from weight matrices (WMs) when these WMs are unknown. Our analysis suggests that the set of all putative sites for a single genome (e.g. E. coli) is largely inadequate for clustering. When sites from different genomes are combined and all the homologous sites from the various species are used as a block, clustering becomes feasible. We predict 50-100 new regulons as well as many new members of existing regulons, potentially doubling the number of known regulatory sites in E. coli.Comment: 27 pages including 9 figures and 3 table

To Seek a New Direction Howard in the Seventies

Dr. James E. Cheek Inauguration Address, April 25, 197

Letter, 1982 October 24, from James E. Cheek to Eva Jessye

1 page, Cheek is the President of Howard University. Gershwin and Porgy and Bess are mentioned

The Plan

Statement by Dr. James E. Cheeck at his first press conference on July8,1969, one week after his arrival on campu

To Seek a New Direction: Howard in the Decade of the Seventies

Address by Dr. James E. Cheek On the Occasion of His Inauguration as the Fifteenth President of Howard University Howard University Campushttps://dh.howard.edu/cheekwrit/1001/thumbnail.jp