Sunday, May 17, 2015

Abstract for seminar at Tel Aviv University

Title: Comparative Genome Analysis


The ENCODE and modENCODE consortia have generated a resource
containing large amounts of transcriptomic data, extensive mapping of
chromatin states, as well as the binding locations of over 300
transcription-regulatory factors for human, worm and fly. The
consortium performed
extensive data integration on this data set. Here
I will give an overview of the data and some of the key analyses.
In particular:

(1) Conservation & Divergence of Transcription

(1a) A novel cross-species clustering algorithm to
integrate the co-expression networks of the three species, resulting in
conserved modules shared between the organisms. These modules are
enriched in developmental genes and exhibited hourglass behavior.

(1b) The extent of the non-coding, non-canonical
transcription is consistent between worm, fly and human.

(1c) In contrast, analyses of pseudogene (fossil genes) show that they
diverged greatly between the organisms, much more so than genes.
Nevertheless, they had a consistent amount of residual transcription.

(2) Conservation of Regulation

(2a) A global optimization algorithm to examine the
hierarchical organization of the regulatory network.
Despite extensive rewiring of binding targets, high-level organization
principles such as a three-layer hierarchy are conserved across the
three species.

(2b) The gene expression levels in the organisms, both coding
and non-coding, can be predicted consistently based on their upstream
histone marks. In fact, a "universal model" with a single set of
cross-organism parameters can predict expression level for both protein
coding genes and ncRNAs.


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