On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera

In previous diversification mechanisms of B-chromosomes were advanced, and conditions for their origin were summarized (GREEN 1990). In the present work, some examples of B-chromosomes in statu nascendi in grasshoppers with neo XY systems are cited, including two cases described in the present work...

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Autores principales:	Colombo, P.C., Remis, M.I.
Formato:	JOUR
Materias:	B-chromosomes Neo XY systems Orthoptera
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00087114_v50_n2_p151_Colombo
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_00087114_v50_n2_p151_Colombo2023-10-03T14:07:47Z On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera Colombo, P.C. Remis, M.I. B-chromosomes Neo XY systems Orthoptera In previous diversification mechanisms of B-chromosomes were advanced, and conditions for their origin were summarized (GREEN 1990). In the present work, some examples of B-chromosomes in statu nascendi in grasshoppers with neo XY systems are cited, including two cases described in the present work (Sinipta dalmani and Leptysma sp.). It was earlier proposed that increased tolerance to supernumerary Xs due to dosage compensation could contribute to the common occurrence of X-like B-chromosomes within the Orthoptera. This seems to be more frequent among newly arisen neo XY systems, possibly due to X-nondisjunction in heterozygous or hybrid females. Mechanisms of differentiation of X-like Bs are further exemplified in Lepty- sema argentina and Cylindrotettix obscurus. It is also pointed out that small Bs could originate from polysomy of the smallest chromosomes, tolerated because of the few genes involved (exemplified in Cylindrotettix obscurus). Finally, the minute-B category is attributed to residual fragments from whole arm rearrangements, as in Sinipta dalmani, a species with a high frequency of spontaneous and polymorphic rearrangements. © 1997 Taylor and Francis Group, LLC. Fil:Colombo, P.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Remis, M.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00087114_v50_n2_p151_Colombo
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	B-chromosomes Neo XY systems Orthoptera
spellingShingle	B-chromosomes Neo XY systems Orthoptera Colombo, P.C. Remis, M.I. On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
topic_facet	B-chromosomes Neo XY systems Orthoptera
description	In previous diversification mechanisms of B-chromosomes were advanced, and conditions for their origin were summarized (GREEN 1990). In the present work, some examples of B-chromosomes in statu nascendi in grasshoppers with neo XY systems are cited, including two cases described in the present work (Sinipta dalmani and Leptysma sp.). It was earlier proposed that increased tolerance to supernumerary Xs due to dosage compensation could contribute to the common occurrence of X-like B-chromosomes within the Orthoptera. This seems to be more frequent among newly arisen neo XY systems, possibly due to X-nondisjunction in heterozygous or hybrid females. Mechanisms of differentiation of X-like Bs are further exemplified in Lepty- sema argentina and Cylindrotettix obscurus. It is also pointed out that small Bs could originate from polysomy of the smallest chromosomes, tolerated because of the few genes involved (exemplified in Cylindrotettix obscurus). Finally, the minute-B category is attributed to residual fragments from whole arm rearrangements, as in Sinipta dalmani, a species with a high frequency of spontaneous and polymorphic rearrangements. © 1997 Taylor and Francis Group, LLC.
format	JOUR
author	Colombo, P.C. Remis, M.I.
author_facet	Colombo, P.C. Remis, M.I.
author_sort	Colombo, P.C.
title	On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
title_short	On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
title_full	On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
title_fullStr	On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
title_full_unstemmed	On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera
title_sort	on the origin of b-chromosomes: neo xy systems and x-like supernumeraries in orthoptera
url	http://hdl.handle.net/20.500.12110/paper_00087114_v50_n2_p151_Colombo
work_keys_str_mv	AT colombopc ontheoriginofbchromosomesneoxysystemsandxlikesupernumerariesinorthoptera AT remismi ontheoriginofbchromosomesneoxysystemsandxlikesupernumerariesinorthoptera
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On the origin of B-chromosomes: Neo XY systems and X-like supernumeraries in Orthoptera

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