Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera)
A population of Belostoma sp. polymorphic for the sex chromosome determining system has been analyzed. The fundamental karyotype of the species is 2n = 16 = 14 + XY (male), and at different times individuals 2n = 17 have been encountered in a low frequency (27% and 16%, respectively). Sex chromosome...
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1996
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v124_n3_p269_Papeschi http://hdl.handle.net/20.500.12110/paper_00180661_v124_n3_p269_Papeschi |
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paper:paper_00180661_v124_n3_p269_Papeschi2023-06-08T14:39:13Z Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) Papeschi, Alba Graciela animal cell article chromosome polymorphism chromosome variant female Hemiptera karyotype male metaphase chromosome nonhuman sex chromosome species X chromosome Y chromosome Animalia Belostoma Belostomatidae Hemiptera Heteroptera A population of Belostoma sp. polymorphic for the sex chromosome determining system has been analyzed. The fundamental karyotype of the species is 2n = 16 = 14 + XY (male), and at different times individuals 2n = 17 have been encountered in a low frequency (27% and 16%, respectively). Sex chromosome area measurements confirm that the original X chromosome of the XY system has fragmented into two unequal-sized chromosomes (X1 and X2). At male metaphase II, the sex univalents associate in a pseudotrivalent that can show different arrangements (in a chain, in a double-plate, or in other transitional arrangements). Their frequency varies among individuals. The present polymorphic population represents a direct evidence of a multiple sex chromosome system originating through fragmentation of the single X. The different kinds of arrangement of the three sex chromosomes at male metaphase II, and their frequency within each individual suggest that some forces are acting to achieve a double plate arrangement and a regular meiotic behaviour. The maintenance of the polymorphism during more than three years seems to indicate that the new chromosomal variant is neutral, or even could be selectively advantageous. Fil:Papeschi, A.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1996 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v124_n3_p269_Papeschi http://hdl.handle.net/20.500.12110/paper_00180661_v124_n3_p269_Papeschi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
animal cell article chromosome polymorphism chromosome variant female Hemiptera karyotype male metaphase chromosome nonhuman sex chromosome species X chromosome Y chromosome Animalia Belostoma Belostomatidae Hemiptera Heteroptera |
| spellingShingle |
animal cell article chromosome polymorphism chromosome variant female Hemiptera karyotype male metaphase chromosome nonhuman sex chromosome species X chromosome Y chromosome Animalia Belostoma Belostomatidae Hemiptera Heteroptera Papeschi, Alba Graciela Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| topic_facet |
animal cell article chromosome polymorphism chromosome variant female Hemiptera karyotype male metaphase chromosome nonhuman sex chromosome species X chromosome Y chromosome Animalia Belostoma Belostomatidae Hemiptera Heteroptera |
| description |
A population of Belostoma sp. polymorphic for the sex chromosome determining system has been analyzed. The fundamental karyotype of the species is 2n = 16 = 14 + XY (male), and at different times individuals 2n = 17 have been encountered in a low frequency (27% and 16%, respectively). Sex chromosome area measurements confirm that the original X chromosome of the XY system has fragmented into two unequal-sized chromosomes (X1 and X2). At male metaphase II, the sex univalents associate in a pseudotrivalent that can show different arrangements (in a chain, in a double-plate, or in other transitional arrangements). Their frequency varies among individuals. The present polymorphic population represents a direct evidence of a multiple sex chromosome system originating through fragmentation of the single X. The different kinds of arrangement of the three sex chromosomes at male metaphase II, and their frequency within each individual suggest that some forces are acting to achieve a double plate arrangement and a regular meiotic behaviour. The maintenance of the polymorphism during more than three years seems to indicate that the new chromosomal variant is neutral, or even could be selectively advantageous. |
| author |
Papeschi, Alba Graciela |
| author_facet |
Papeschi, Alba Graciela |
| author_sort |
Papeschi, Alba Graciela |
| title |
Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| title_short |
Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| title_full |
Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| title_fullStr |
Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| title_full_unstemmed |
Sex chromosome polymorphism in a species of Belostoma (Belostomatidae, Heteroptera) |
| title_sort |
sex chromosome polymorphism in a species of belostoma (belostomatidae, heteroptera) |
| publishDate |
1996 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v124_n3_p269_Papeschi http://hdl.handle.net/20.500.12110/paper_00180661_v124_n3_p269_Papeschi |
| work_keys_str_mv |
AT papeschialbagraciela sexchromosomepolymorphisminaspeciesofbelostomabelostomatidaeheteroptera |
| _version_ |
1768543212988792832 |