Abstract:
Twenty-four males of Cylindrotettix obscurus and ten of C. santarosae (Leptysminae, Acrididae) from Rio Claro, Brazil, were cytologically analysed. Both species are 2n = 23 ♂ (22+XO), all chromosomes being telocentric except for 4 acrocentric pairs of C. obscurus. Two different B-chromosomes were found in C. obscurus: (1) a small, mitotically unstable telocentric (BT) and (2) a medium-sized, mitotically stable submetacentric (B1). B1 has a large pericentromeric heterochromatic portion and two distal euchromatic segments where both terminal associations and interstitial chiasmata are regularly formed producing a ring univalent at prophase I. B1 is almost certainly an iso-chromosome which has undergone a centromeric shift through pericentric inversion or centric transposition (heterochromatin duplication or deletion could also be the cause of arm inequality). In C. santarosae, a single male carried a small mitotically stable telocentric B-chromosome. Both B types of C. obscurus significantly increased the production of abnormal sperm (diploid, tetraploid and micro-spermatids) when compared to 0B individuals although their effects were differential: BT induced higher frequencies of microspermatids especially in those follicles with odd BT numbers, while in B1 carriers the increase was chiefly due to polyploid spermatids. None of the Bs of C. obscurus affected cell mean chiasma frequency nor the between-cell variance. The B of C. santarosae had no effect on abnormal sperm production but it probably increased cell mean chiasma frequency. © 1986 Dr W. Junk Publishers.
Registro:
Documento: |
Artículo
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Título: | The B-chromosomes of two species of Cylindrotettix (Leptysminae, Acrididae) |
Autor: | Confalonieri, V.A.; Bidau, C.J. |
Filiación: | Becaria Conicet, Argentina Laboratorio de Genética, Depto Ciencias Biológicas, Fac. Cs Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, Buenos Aires, 1428, Argentina
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Año: | 1986
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Volumen: | 68
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Número: | 2
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Página de inicio: | 87
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Página de fin: | 95
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DOI: |
http://dx.doi.org/10.1007/BF02424404 |
Título revista: | Genetica
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Título revista abreviado: | Genetica
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ISSN: | 00166707
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CODEN: | GENEA
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Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166707_v68_n2_p87_Confalonieri |
Referencias:
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- Hewitt, G.M., Orthoptera (1979) Animal Cytogenetics 3. Insecta 1, , B., John, Borntraeger, Berlin-Stuttgart
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- Schroeter, G.L., Hewitt, G.M., The effects of supernumerary chromatin in three species of grasshoppers (1974) Can. J. Genet. Cytol., 16, pp. 285-296
- Stephens, R.T., Bregman, A.A., The B-chromosome system of the grasshopper Melanoplus femur-rubrum (1972) Chromosoma, 38, pp. 297-311
- Vilardi, J. C., 1985. Meiotic behaviour in a population of Dichroplus elongatus (Orthoptera: Acrididae). Caryologia (in press); White, M.J.D., (1973) Animal cytology and evolution, , 3rd Edit., Cambridge Univ. Press, London
Citas:
---------- APA ----------
Confalonieri, V.A. & Bidau, C.J.
(1986)
. The B-chromosomes of two species of Cylindrotettix (Leptysminae, Acrididae). Genetica, 68(2), 87-95.
http://dx.doi.org/10.1007/BF02424404---------- CHICAGO ----------
Confalonieri, V.A., Bidau, C.J.
"The B-chromosomes of two species of Cylindrotettix (Leptysminae, Acrididae)"
. Genetica 68, no. 2
(1986) : 87-95.
http://dx.doi.org/10.1007/BF02424404---------- MLA ----------
Confalonieri, V.A., Bidau, C.J.
"The B-chromosomes of two species of Cylindrotettix (Leptysminae, Acrididae)"
. Genetica, vol. 68, no. 2, 1986, pp. 87-95.
http://dx.doi.org/10.1007/BF02424404---------- VANCOUVER ----------
Confalonieri, V.A., Bidau, C.J. The B-chromosomes of two species of Cylindrotettix (Leptysminae, Acrididae). Genetica. 1986;68(2):87-95.
http://dx.doi.org/10.1007/BF02424404