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Genetic analysis of some factors affecting mitotic and meiotic behavior of a mutant of Aspergillus nidulans

José Moacir Marin^I; Tânia M.A. Domingues Zucchi^II

^IDepartamento de Ciências Morfológicas, Faculdade de Odontologia-USP, 14049 Ribeirão Preto, SP, Brasil
^IIDepartamento de Parasitologia, Instituto de Ciências Biomédicas - USP, Av. Prof. Lineu Prestes, 1374, Cidade Universitária, 05508 São Paulo, SP, Brasil. Send correspondence to T.M.A.D.Z.

ABSTRACT

This study describes and characterizes a MNNG (N-methy-N'-nitro-N-nitrosoguanidine) induced mutant of Aspergillus nidulans presenting abnormal meiotic recombination frequencies in the w-meth interval of chromosome II. The mutant was selected on the basis of its unstable character, which originated spontaneous, improved or deteriorated sectors. Genetic analysis of several deteriorated sectors evidenced mitotic instability, morphological alterations UV sensitivity (uvs) and an apparent increase in the recombination frequency in the w-meth interval, suggesting a meth⁺ duplication in the paba-y interval of chromosome I (Dp II-I). The uvs character and deteriorated morphology (det) of mitotic segregants seemed the direct outcome of the duplication insertion.
The significant increase in meth-w recombination frequency was related to the expression of the meth⁺ character in the transposed element, since the spontaneous sectors, arising from deteriorated sectors, presented normal w-meth recombination frequencies, normal colony morphology and a completely restored mitotic stability.

Keywords: Mitotic; Meiotic; Mutant; Aspergillus nidulans.

REFERENCES

Azevedo, J.L. (1971). Mitotic non-conformity in Aspergillus nidulans. Ph.D. Thesis, England University of Sheffield, 240 p.

Azevedo, J.L. (1975). Altered instability due to genetic changes in a duplication strain of Aspergillus nidulans. Gen. Res. 26: 55-61.

Azevedo, J.L. and Roper, J.A. (1970). Mitotic non conformity in Aspergillus: sucessive and transposable genetic changes. Gen. Res. 16: 79-93.

Baimbridge, B.W. and Roper, JA. (1966). Observations on the effects of a chromosome duplication in Aspergillus nidulans. J. Gen. Microbiol. 42: 417-424.

Case, B.L. and Roper, JA. (1981). Mitotic processes which restore genome balance inAspergillusnidulans. J. Gen. Microbiol. 124: 9-16.

Clutterbuck, AJ. (1974). Aspergillus nidulans. In: Handbook of Genetics 1(King, R.C. ed.). Plenum Press, New York, pp. 447-510.

Clutterbuck, A.J. (1981). Loci and linkage map of Aspergillus nidulans. Aspergillus News Letters 15: 58-72.

Clutterbuck, A.J. (1987). Loci and linkage map of the filamentous fungus Aspergillus nidulans (O'Brien, S.L., ed.). Genetic maps. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.

Daud, F., Ortori, G.S. and Roper, JA. (1985). Spontaneous I.R. duplications generated at mitosis in Aspergillus nidulans: further evidence of a preferential site of transposed attachment. Genetics 110:229-245.

Jansen, G.J.O. (1967). Some properties of the uvs 1 mutant of Aspergillus nidulans. Aspergillus Newsletter 8: 20-21.

Jansen, G.J.O. (1970a). Survival of uvs B and uvs C mutants of Aspergillus nidulans after UV irradiation. Mutat. Res. 10: 21-32.

Jansen, G.J.O. (1970b). Abnormal frequencies of spontaneous mitotic recombination in uvs B and uvs C mutants of Aspergillus nidulans. Mutat. Res. 10: 33-41.

Majerfeld, I.H. and Roper, JA. (1978). The effects of coumarin on the frequency of deletions in a duplication strain of Aspergillus nidulans. Mol. Gen. Genet. 159: 203-206.

Neves, P. and Saedler, H. (1977). Transposable genetic elements as agents of gene instability and chromosomal rearrangements. Nature 268: 109-115.

Nga, B.H. and Roper, JA. (1968). Quantitative intrachromosomal changes arising at mitosis in Aspergillus nidulans. Genetics .58: 193-209.

Pontecorvo, G., Roper, JA., Hemmons, L.M., MacDonald, K.D. and Bufton, A.W.J. (1953). The genetics of Aspergillus nidulans. Adv. Genet. 5: 141-238.

Pritchard, RH. (1956). A genetic investigation of some adenine requiring mutants of Aspergillus nidulans. Ph.D. Thesis, England, University of Glasgow.

Van de Vate, C. and Jansen, G.J.O. (1978). Meiotic recombination in a duplication strain of Aspergillus nidulans. Genet. Res. 31: 29-52.

Zucchi, T.M.A.D. (1986). Estudos de fatores genéticos que alteram as freqüências de recombinação em Aspergillus nidulans EIDAM (Winter). "Livre Docência" Thesis. Faculdade de Odontologia - USP, Ribeirão Preto.

Zucchi, T.MA.D. and Azevedo, J.L. (1979). Mitotic instability in a III-VIII duplications strain of Aspergillus nidulans. Rev. Bras. Genet. 2: 93-108.

Zucchi, T.M.A.D. (1990). Isolation of putative recombination mutants of Aspergillus nidulans. Rev. Bras. Genet. 13: 409-424.