We have applied a birefringent acousto-optic crystal for wavelength tuning of a Ti:sapphire laser. A continuous-tuning range of 12 nm, which was limited by wavelength-dependent angle deviation of the beam def lection in the crystal, was extended to over 100 nm by optical correction. Fast and random access of lasing wavelengths by direct electronic tuning was demonstrated at a pulsed operation of 10 Hz.

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The Afa-family repetitive sequences were isolated from barley (Hordeum vulgare, 2n = 14) and cloned as pHvA14. This sequence distinguished each barley chromosome by in situ hybridization. Double color fluorescence in situ hybridization using pHvA14 and 5S rDNA or HvRT-family sequence (subtelomeric sequence of barley) allocated individual barley chromosomes showing a specific pattern of pHvA14 to chromosome 1H to 7H. As the case of the D genome chromosomes of Aegilops squarrosa and common wheat (Triticum aestivum) hybridized by its Afa-family sequences, the signals of pHvA14 in barley chromosomes tended to appear in the distal regions that do not carry many chromosome band markers. In the telomeric regions these signals always placed in more proximal portions than those of HvRTfamily. Based on the distribution patterns of Afa-family sequences in the chromosomes of barley and D genome chromosomes of wheat, we discuss a possible mechanism of amplification of the repetitive sequences during the evolution of Triticeae. In addition, we show here that HvRT-family also could be used to distinguish individual barley chromosomes from the patterns of in situ hybridization.