REPEATED DNA SEQUENCE-350 BY FAMILY CLONE D FROM AGROPYRON-INTERMEDIUM FOR IDENTIFICATION OF THE AGROPYRON CHROMOSOMES ADDED TO COMMON WHEAT LINES

Repeated DNA sequences cloned from Agropyron intermedium (2n =42, E1E1 E2E2XX) enabled to identify the Ag. intermedium chromosomes in the com mon wheat genome by Southern and in situ hybridization. Four repetitiv e DNA clones that did not hybridize to the total genomic DNA of Tritic um aestivum cv. Chinese Spring (CS) were screened from the Mbo I-diges ted genomic DNA library of Ag. intermedium. These clones were grouped into two representative repeated clones, pTA100 and pTA28, based on th e Southern hybridization patterns of genomic DNA of Ag. intermedium. T he clone pTA100 hybridized to the 350 bp tandem repeated family define d by digestion with EcoO109 I. The clone pTA100 showed homology with t he EcoO109 I-380 bp tandem repeated family of rye (Tomita et al. 1993) , which belonged to the 350 bp family of rye (Bedbrook et al. 1980, Ap pels et al. 1986). The clone pTA28 hybrdized to four kinds of repeated fragments, 6800 bp, 6200 bp, 3600 bp and 1850 bp defined by digestion with Eco O109 I. The clone pTA100 used as a probe did not exhibit hyb ridization signals based on both genomic Southern and chromosomal in s itu analysis for the amphiploid AgCS (2n = 56, AABBDDEE) between CS (2 n = 42, AABBDD) and Ag. elongatum (2n = 14, EE). This finding indicate d that the pTA100 family was absent in the E genome. However, the clon e pTA100 hybridized to the terminal regions of the ten pairs of chromo somes in Ag. intermedium. These results indicated that at least three pairs of chromosomes belonged to the E1 genome or E2 genome and the se gments of the hybrid region in these chromosomes must have originated from the X genome. The clone pTA100 was used as a probe for Southern h ybridization to seven kinds of Wheat-Ag. intermedium chromosome additi on lines. The 350 bp tandem patterns were observed in the addition lin es A, B, C and D, while no hybridization was observed in the remaining three addition lines. Moreover, based on chromosomal in situ analysis the clone pTA100 hybridized to the terminal region of the short arm o f added chromosome A, the terminal region of the long arm of added chr omosome B and the terminal region of both arms of added chromosomes C and D. As the added chromosomes C and D differed in their arm ratios, it was possible to distinguish these four added chromosomes from each other by the ISH site of the clone pTA100. It is considered that the t hree kinds of added chromosomes A, B and D showing the ISH site of the clone pTA100 and faint C-bands may have originated from the X genome of Ag. intermedium.