Dp(1)22H

This mutation was identified among the progeny of a (C3H/HeH x 101/H)F1 male mouse that had received triethylenemelamine on day 1 and hydroxyurea (HU) and HU plus 6 Gy X-rays, at 3-hr intervals, on day 2 and later was mated to tester (PT) females. Cytogenetic analysis indicates that the duplication involves G-bands 1F and 1G and increases the length of Chr 1 by ~10%. The absence of quadrivalents at diakinesis of meiosis I in spermatocytes of an affected male confirms that the additional material is not derived from another chromosome. (J:192801)