title: [Mating types in the ciliate Dileptus anser. Genetical instability in the mating type system].
abstract: In F1 and F2 from a cross between two clones of Dileptus anser isolated from natural sources (MT 1 x x MT III; MT = mating type), along with "normal" clones, many clones were observed demonstrating abnormal phenotype with respect to the MT-character. Irregular features of the latter were as follows: a) a delay in maturation; b) temporary reversion to immature or adolescent state, which means instability of maturity state; c) expression of MT I and MT III, rather than MT II as in properly matured clones; d) changes in MT (i.e., MT instability); e) appearance of totally unexpected MTs in terms of the scheme of genetic control of MTs in D. anser previously suggested by Afon'kin and Yudin (1987)--e.g., of all three MTs in F1 from the initial (analysing!) cross. Amazingly, these abnormal D. anser clones closely resembled some selfer-clones of Tetrahymena pigmentosa, previously reported as an example of genetic instability in the ciliate MT system (Simon, 1980; Simon, Orias, 1987).
authors.affiliation: Institute of Cytology, RAS, St. Petersburg.
authors.forename: Z I
authors.initials: ZI
authors.lastname: Uspenskaia
authors.forename: A L
authors.initials: AL
authors.lastname: Iudin
mesh_terms: D000818:Animals; D016798:Ciliophora / Q000235:genetics* / Q000254:growth & development; D002999:Clone Cells; D042822:Genomic Instability; D010641:Phenotype; D013997:Time Factors