Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
In large-genome species such as wheat (2n=6x=42), genes are distributed non-randomly across the genome. Large-scale mapping of expressed sequenced tags (ESTs) has demonstrated that distal chromosome regions contain higher gene densities compared to proximal regions. The general view of the organization of the wheat genome is that genes are organized in gene islands that consist of one or more genes and are separated by large stretches of repetitive DNA. However, it is not known whether or to what extent the sizes of gene islands vary in gene-rich and gene-poor regions. We are in the process of analyzing the interspersion patterns of genes and repeats in the hexaploid wheat genome in more detail by sequencing 220 randomly selected BAC clones from Chinese Spring wheat, annotating these BAC clones for gene content, and mapping them to previously identified regions of high and low gene density. The obtained data will be used to project the number of genes present in hexaploid wheat, the size and number of gene islands, and consequently, the minimum number of BAC clones that would need to be sequenced in a whole-genome-sequencing project to identify 95% or more of all wheat genes.
The outline of a new NSF-funded project, entitled ‘Gaining Insight into the Organization and Evolution of Genomes through Wheat - Brachypodium - Rice Comparative Analysis’ will also be discussed. This project aims to assess the use of Brachypodium as a model for wheat genome studies through comparative analyses at the map and sequence level, and to study variation in recombination and synteny erosion along the telomere – centromere axis.