Identification and mapping of polymorphic SSR markers from expressed gene sequences of barley and wheat
2002
Holton, T.A. | Christopher, J.T. | McClure, L. | Harker, N. | Henry, R.J.
The growing availability of EST sequences from a range of crop plants provides a potentially valuable source of new DNA markers. We have examined the International Triticeae EST Cooperative database for the presence of dinucleotide and trinucleotide simple sequence repeats. Analysis of 24,344 ESTs identified 388 dinucleotide repeats and 978 trinucleotide repeats in ESTs, representing 1.6% and 4.0% of the total number of ESTs, respectively. To test the utility and cross-species transferability of EST-derived SSR markers, primers were designed to the flanking regions of 41 barley SSRs and used to screen 11 barley and 15 wheat varieties. Sixteen of the barley SSR markers were polymorphic in barley and five were polymorphic in wheat. This represents a relatively high level of transferability of SSR markers between barley and wheat, which has important implications for the development of new markers and comparative mapping of barley, wheat and other cereals. An additional 56 SSRs from wheat ESTs were tested in the same barley and wheat varieties. Four wheat EST SSR markers were polymorphic in wheat and one in barley. Chromosomal locations in barley and wheat were determined for the majority of polymorphic markers.
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