Characterization of telomeres in Hordeum vulgare chromosomes by in situ hybridization. II. Healed broken chromosomes in telotrisomic 4L and acrotrisomic 4L4S lines
1992
Wang, S. | Lapitan, N.L.V. | Roder, M. | Tsuchiya, T.
The ends of barley chromosomes hybridize in situ to the telomeric sequences of Arabidopsis thaliana. It was confirmed that the cross-hybridizing sequences in barley are found at the absolute ends of the chromosomes by exonuclease Bal31 digestion. The Bal31 experiments also indicated that telomere-like sequences do not occur in high copies at interstitial sites in barley. To determine whether healing of broken chromosomes occurred in aneuploid lines of barley containing extra chromosomes with breakages in different parts, in situ hybridization with the A. thaliana telomere on telotrisomic 4L and acrotrisomic 4L(4S) lines was conducted. Telosome 4L possesses breaks in the centromere and in an interstitial location in the long arm, while acrosome 4L(4S) possesses interstitial breaks in both long and short arms. In situ hybridization revealed the presence of telomere sequences on both broken ends of telosome 4L and acrosome 4L(4S). In telosome 4L, telomere sequences were present even at the broken site of the centromere. These results show that broken ends of barley chromosomes were healed. Such healing may explain the stability of these chromosomes through many generations.
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