Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2006
Publication Date: 2/28/2006
Citation: Sargent, D.J., Clarke, J., Simpson, D.W., Arus, P., Monfort, A., Vilanova, S., Denoyes-Rothan, B., Folta, K.M., Bassil, N.V., Battey, N.H. 2006. An enhanced microsatellite map of diploid fragaria. Theoretical and Applied Genetics. 112:1349-1359. Interpretive Summary: Linkage maps identify blocks of markers and genes that are closely associated. Ideally, each linkage group corresponds to a chromosome. Linkage groups are important because they help in identifying the location of genes of interest. DNA markers serve as genetic landmarks and are interspersed among the genes throughout the chromosomes of strawberry. In this research, one hundred and nine SSR markers were added to a linkage map of the diploid strawberry in an F2 mapping population (FVxFN) derived from a cross between F. vesca 815 and F. nubicola 601. The map was grouped into seven expected groups. Placing SSR markers on this map will make it useful in the cultivated strawberry and in other Rosaceous crops. It provides a framework upon which to place universal markers, such as genes of known function, for comparative mapping purposes and to isolate important genes that are responsible for traits of interest.
Technical Abstract: A total of 45 microsatellites (SSRs) were developed for mapping in Fragaria. They included 31 novel codominant genomic microsatellites (SSRs) from Fragaria nubicola and a further 14 derived from an expressed sequence tagged library (EST-SSRs) of F. x ananassa. These, and an additional, 64 previously characterised SSRs and EST-SSRs, were scored in the diploid Fragaria interspecific F2 mapping population (FVxFN) derived from a cross between F. vesca 815 and F. nubicola 601. The cosegregation data of these, and of 73 previously mapped molecular markers, were used to elaborate an enhanced linkage map. The map is composed of 182 molecular markers (175 microsatellites, six gene specific markers and one sequence-characterised amplified region) and spans 424 cM over seven linkage groups. The average marker spacing is 2.3 cM / marker and the map now contains just eight of gaps over 10 cM. The transferability of the novel SSR markers to the cultivated strawberry F. x ananassa was demonstrated using eight cultivars. Because of the transferable nature of these markers, the map produced will provide a useful reference framework for the development of linkage maps of the cultivated strawberry F. x ananassa and for the development of other key resources for Fragaria such as a physical map. In addition, the map now provides a framework upon which to place transferable markers, such as genes of known function, for comparative mapping purposes within Rosaceae.