Poster: Genomics Resources

Abs # 952: Physical mapping gene-rich BAC clones on corn pachytene chromosomes

Presenter:	Ananiev, Evgueni , evgueni.ananiev@pioneer.com
Authors	Ananiev, Evgueni  (A)   Chamberlin, Mark  (A)   Svitashev, Sergei  (A)   Fengler, Kevin  (A)   Tingey, Scott  (A)
Affiliations:	(A): Pioneer HiBred a DuPont Company

More than 10,000 ESTs have been already mapped on the collection of BAC clones comprising a DuPont corn Mo17 genomic library. The distribution of the ESTs among different BAC clones is highly uneven. This enabled us to identify a group of BAC clones, which are enriched with different ESTs and composed of significant number of unique or low-copy nucleotide sequences. Such gene-rich BAC clones were used as labeled probes for physical mapping on pachytene corn chromosomes with the help of in situ hybridization. Twenty BAC clones were identified up to now, which gave localized positive signal on pachytene chromosomes after suppression of repetitive DNA with the help of Cot 1 DNA fraction. PCR tests on oat-corn chromosome addition lines were used to assign cytological markers to corn specific chromosomes. Gene-rich BAC clones were used as cytological landmarks for mapping other unique and clustered repeated DNA sequences such as 5S rDNA, AGT-micro satellites, knob, and centromere-specific repeats. This approach enabled us to produce the first cytogenetical physical map of corn genome for major clustered repeats