A ZEBRA CHROMOSOME ARISING FROM MULTIPLE TRANSLOCATIONS INVOLVING NONHOMOLOGOUS CHROMOSOMES

An alloplasmic wheat line carrying a 'zebra' chromosome z5A was isolat ed from the derivatives of an Elymus trachycaulus x Triticum aestivum cv Chinese Spring hybrid. Chromosome z5A was named zebra because of it s striped genomic in situ hybridization pattern. z5A consists of four chromosome segments derived from E. trachycaulus and four chromosome s egments, including the centromere, from wheat. The short arm o z5A pai red with the telocentric chromosome 1H(t)S of E. trachycaulus and the long arm with the long arm of normal 5A. z5A also carried several gene tic markers derived from 1H(t)S. Chromosome 1H(t) was the only E. trac hycaulus chromosome found in the sib plants of a previous generation f rom which z5A was derived. Monosomic 5A and telocentric chromosome 5AL were also found in most of the sib plants. The zebra chromosome most probably originated from spontaneous multiple translocations between c hromosomes 5A and 1H(t)S or 5A and 1H(t).