BGN 29: Coordinator's Report: Chromosome 4H

Coordinator's Report: Chromosome 4H

B.P. Forster

Cell and Molecular Genetics Department
Scottish Crop Research Institute
Invergowrite, Dundee DD2 5DA, UK


Genetic maps of barley, including chromosome 4 are now emerging which include simple sequence repeats (SSRs, or microsatellites). Recently published SSR maps can be found in Liu et al. (1996), Waugh et al. (1997b); and Thomas et al. (1998). In addition to SSRs other new marker systems such as, Bare-1 loci detected by sequence-specific amplification polymorphism (S-SAP) of retrotransposon like elements, have been used in barley genome mapping (Waugh et al. (1997a). Bare-1 and SSR loci have been used to identify a quantitative trait locus (QTL) decreasing yield and linked to the powdery mildew resistance locus, mlo on barley chromosome 4 (Thomas et al. (1998). Genetic markers have also been used to map physiological traits in barley. Effects for the traits dry weight, delta15N and delta13C were reported to be associated with an AFLP marker on the long arm of chromosome 4 (Ellis et al. 1997). Recently, Eglington et al. (1998), mapped a QTL for beta- amylase thermostability corresponding to the Bmy1 gene on the long arm of chromosome 4.

The past five years have seen much activity in mapping molecular genetic markers (RFLPs, RAPDs, AFLPs, SSRs, S-SAPs). Chromosome maps of barley were originally intended to be gene maps, and there is now a significant shift back to gene mapping. Genetic marker maps, particularly those involving reliable and transferable markers, are now being exploited in mapping traits of interest, including quantitatetively inheritated traits. Libraries of expressed sequence tags (ESTs) are also being exploited to find the locations of genes active in specific tissues, environments, and industrial processes. It is anticipated that the growing interest in functional genomics will provide further impetus in gene mapping.

References:

Eglinton, J.K., P. Langridge, and D.E. Evans. 1998. Thermostability variation in alleles of barley beta-amylase. J. Cer. Science 28:301-309.

Ellis, R.P., B.P. Forster, R. Waugh, N. Bonar, L.L. Handley, D. Robinson, D.C. Gordon, and W. Powell. 1997. Mapping physiological traits in barley. New Phytol. 137:149-157.

Liu, Z.W., R.M. Biyashev, and M.A. Saghai Maroof. 1996. Development of simple sequence repeat DNA markers and their integration into a barley linkage map. Theor. Appl. Genet. 93:869-876. Thomas W.T.B., E. Baird, J.D. Fuller, P. Lawrence, G.R. Young, J. Russell, L. Ramsay, R. Waugh, and W. Powell. 1998. Identification of a QTL decreasing yield in barley linked to Mlo powdery mildew resistance. Mol. Breeding 4:381-393.

Waugh, R., K. McLean, A.J. Flavell, S.R. Pearce, A. Kumar, W.T.B. Thomas, and W. Powell. 1997a. Genetic distribution of Bare-1-like retrotranspoable elements in the barley genome revealed by sequence-specific amolification polymorphisms (S-SAP). Mol. Gen. Genet. 253:687-694.

Waugh, R., M. Macaulay, K. McLean, J. Fuller, N. Bonar, L. Ramsay, and W. Powell. 1997b. Development of a simple sequence repeat-based linkage map of barley. In: W.H. Macfarlane Smith and T.D. Heilbronn (eds.) Annual Report of the Scottish Crop Research Institute for 1996/97, pp. 82-84.


table of contents | BGN main index