Gramene Newsletter

GRAMENE News

Volume 2 Issue 4
July/August 2007

Do you have news to share?

The Gramene Newsletter is a community resource about cereals and cereal genomics. It is a forum for community members to share news and current events. Some ideas for contributions include:

Articles, news items, events, opportunities or inquiries should be submitted to the GrameneNews editor at cer17@cornell.edu. Gramene reserves the right to select contributions which meet the educational mission of the publication. Photos are also encouraged. Please provide print quality photos (300dpi) images, credit and caption information.

Introduction to Gramene contributor project: Panzea

The ultimate germplasm resource to date for localizing QTLs in maize!

The Panzea project (NSF DBI 0321467) is a five-year NSF project headed by John Doebley, and involves eight additional investigators at seven institutions (University of Wisconsin, Cornell University, North Carolina State University, University of Missouri, University of California-Irvine, Cold Spring Harbor Laboratory and USDA-ARS). Our overall objectives are to address two major questions: 'How has selection shaped molecular diversity?' and 'How does this molecular diversity relate to functional trait variation?' We have completed our objectives relating to our first major question, and you can read more about the results to date from this project (and from its five-year forerunner) at http://www.panzea.org/lit/publication.html.

Now we are devoting our focus to the characterization of functional diversity in both teosinte and maize. We are engaged in QTL and association mapping experiments both in modern maize and in crosses between teosinte and maize. We are currently working with two teosinte association mapping populations, three teosinte-maize backcross QTL mapping populations, a maize association mapping population and a maize 'Nested Association Mapping' (NAM) population.

The maize NAM population is the centerpiece of our project - we expect this population to be the most significant to the maize research community. Nested Association Mapping is a powerful new method for localizing QTL which uses a multifamily RIL mapping population derived from crosses to a common parent (i.e., B73) in order to perform a joint QTL and association analysis. By employing a genomic scan of common parent-specific SNPs in the progeny RILs combined with high density genotyping (or sequencing) of the parental lines, the NAM strategy captures the best of both worlds: the statistical power of QTL analysis is combined with the high chromosomal resolution of association analysis.

We are pioneering the NAM approach in maize. Our NAM population consists of >5000 RILs from 25 families, with 200 RILs per family, all being genotyped at 1500 SNP loci. It forms a permanent QTL mapping resource for the benefit of the maize and grass communities. The families were generated by crossing 25 diverse maize inbred lines with B73 as the common parent, and the well-known IBM mapping population is included as the 26th family. Finally, a collection of 280 diverse maize inbreds from around the world has been included to serve as an association mapping platform for maize. We have recently demonstrated the power of our NAM population for detecting higher order epistatic interactions among QTL, using simulated data based upon actual SNP genotypes from our 25 NAM parents (Stich et al., Genetics 176:563-70, 2007).

Cornell Maize Geneticists and "The McClintock Shed"

Meet the amazing team of researchers who set a high standard of excellence for future geneticists, here pictured in front of their field house in 1929, the building that still stands next to the Pounder Heritage Garden in the Cornell Plantations.