ITHACA, N.Y. -- Andrew Simpson, a senior geneticist with the Ludwig Institute for Cancer Research in São Paulo, Brazil, will discuss the challenges that remain in decoding the human genome in a lecture at Cornell University on Wednesday, Feb. 12, at 4 p.m. in Room G-10 of the Biotechnology Building.

His lecture, titled "Transcriptomics: The Link Between Sequencing the Human Genome and Human Biology," is free and open to the public. It is the third in a series of lectures sponsored by the Cornell/Ludwig Institute for Cancer Research Partnership.

Simpson, who also is director of the Ludwig Institute's James R. Kerr Program, led the Brazilian effort to sequence the bacterium Xylella fastidiosa , the first genome sequencing to be completed outside of the United States, Europe or Japan. The organism causes severe damage to citrus trees and the citrus industry.

In his talk Simpson will note that although sequencing of the human genome is almost complete, a second massive sequencing effort must be undertaken to permit gene identification. That effort will be searching for genetic annotations, or "transcripts."

Simpson will describe how a large group of scientists in Brazil, coordinated by the Ludwig Institute, has contributed about 1 million sequences from transcripts present in tumors and normal tissues to public databases.

"We are now embarking on the precise quantification of gene expression using novel sequencing methods that are capable of generating several million short tags from individual transcripts within cells," says Simpson.

The genetic sequencing is capable of tagging even the rarest of messages that have previously eluded detection. Says Simpson: "We have now moved in the space of two years from gene discovery within the human genome to precise quantification of gene expression and transcript variability using the same basic technique of human transcript sequencing."