PAG-XVII  Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA


P420 : Fruit Trees

Using Pentaploids As Tools For Studying Genomic Composition And Allele Transmission Patterns In Octoploid Fragaria.

Elizabeth G Poulsen1 , Linyuan Li2 , Thomas M Davis1

1  University of New Hampshire, Department of Biological Sciences,Rudman Hall, Durham, NH 03824 USA
2  University of New Hampshire, Department of Mathematics, Kingsbury Hall, Durham, NH 03824 USA

A unique pentaploid population of Fragaria (strawberry) was developed to gain insight into octoploid genome composition and allele transmission patterns. The pentaploid population was produced by first crossing representatives of two divergent subspecies of F. virginiana (ssp. glauca and ssp. virginiana) and then by crossing F1 plant LB48 with F. vesca, the diploid strawberry model species. The resulting pentaploid progeny population inherited four sets of chromosomes from octoploid LB48 and one set from the F. vesca parent. With the objective of examining patterns of allele transmission from an octoploid, the intergenic region of the gRGA1-Subtilase gene pair locus was amplified, and PCR products were cloned, sequenced, and compared to define the allele composition of LB48. A mathematical formula was devised and employed to calculate the number of sequences needed to assure 99% confidence that all possible alleles were sampled. The sequencing data revealed three distinct haplotypes and additional subtypes. Genotyping was then performed on pentaploid progeny: PCR with fluorescently labeled primers being coupled with a restriction digest and fragment analysis. From the genotyping results, it was possible to determine which alleles from LB48 were present in each pentaploid progeny plant. This result establishes the potential value of our pentaploid progeny population as a resource for analysis of octoploid allele transmission patterns in strawberry. This project was supported in part by the National Research Initiative Plant Genome Program of USDA’s Cooperative State Research, Education and Extension Service.