title: Chromosomal instability in the cattle clones derived by somatic cell nuclear-transfer.
abstract: Cytogenetic analysis was performed on peripheral lymphocytes collected from 20 cattle clones (19 showed no overt phenotypic abnormalities except for high birth weight while 1 exhibited left forelimb contracture), the donor cell cultures from which they were derived and lymphocytes from six insemination produced control cattle. All animals and cell cultures had a modal chromosome number of 60. The frequency of abnormal cells for donor cell cultures, clones, and controls was 6.68+/-0.30%, 5.30+/-5.49%, and 5.08+/-1.04%, respectively, and did not differ significantly among the groups. There were, however, two clones derived from different donor cell cultures with high incidences of 21.29% and 20.13%, of abnormal cells consisting of pseudodiploid (near-diploid), near-triploid and near-tetraploid, and tetraploid cells. Among these two clones, one had only a few endoreduplicated nuclei although further studies are necessary to precisely define the cytological origin and nature of the abnormal cells. The clones were evaluated at multiple time points for up to 20 months of age and the incidence of abnormal lymphocytes remained stable indicating that the chromosomally abnormal nuclei found in cloned animals was not a transient event. These results show that the majority of phenotypically normal clones have normal chromosomal make up but that instability of chromosome number can occur in clones that are phenotypically normal. Therefore, cytogenetical evaluation of peripheral lymphocytes and other tissues with follow up of the phenotypical consequences of these abnormalities is warranted even in phenotypically normal clones.
authors.affiliation: Department of Animal Science, Tokyo University of Agriculture, Atugi, Japan. hhhanada@nodai.ac.jp
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hanada
authors.forename: Kumiko
authors.initials: K
authors.lastname: Takeda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tagami
authors.forename: Keijiro
authors.initials: K
authors.lastname: Nirasawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Akagi
authors.forename: Noritaka
authors.initials: N
authors.lastname: Adachi
authors.forename: Seiya
authors.initials: S
authors.lastname: Takahashi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Izaike
authors.forename: Masaki
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Dai-Ichiro
authors.initials: D
authors.lastname: Fuchimoto
authors.forename: Norikazu
authors.initials: N
authors.lastname: Miyashita
authors.forename: Masanori
authors.initials: M
authors.lastname: Kubo
authors.forename: Akira
authors.initials: A
authors.lastname: Onishi
authors.forename: W Allan
authors.initials: WA
authors.lastname: King
mesh_terms: D000375:Aging / Q000235:genetics; D000818:Animals; D002417:Cattle / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics*; D043171:Chromosomal Instability / Q000235:genetics*; D033481:Chromosomes, Mammalian / Q000235:genetics; D019976:Cloning, Organism; D008677:Metaphase / Q000235:genetics; D053652:Nuclear Transfer Techniques; D027724:Reproductive Techniques, Assisted; D016615:Telomere / Q000235:genetics