Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)

The karyotype of Baccharis coridifolia DC., a dioecious diploid species consists of 16 chromosomes with median (m) and 2 with submedian centromeric positions (sm) (2n = 18). Meiotic analyses of 219 male plants belonging to 12 populations showed across a wide geographical range one quadrivalent and s...

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Autor principal: Wulff, Arturo Federico
Publicado: 2002
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v137_n2_p132_Hunziker
http://hdl.handle.net/20.500.12110/paper_00180661_v137_n2_p132_Hunziker
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spelling paper:paper_00180661_v137_n2_p132_Hunziker2023-06-08T14:39:17Z Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae) Wulff, Arturo Federico allele article Asteraceae centromere chromosome chromosome bivalent chromosome translocation controlled study diploidy dominant gene flowering genetic linkage geographic distribution heterozygosity karyotype meiosis metaphase nonhuman plant insect interaction pollen pollen mother cell pollination population genetics recessive gene sex ratio suppressor gene Asteraceae Chromosomes, Plant Heterozygote Translocation, Genetic Asteraceae Baccharis Embryophyta Insecta The karyotype of Baccharis coridifolia DC., a dioecious diploid species consists of 16 chromosomes with median (m) and 2 with submedian centromeric positions (sm) (2n = 18). Meiotic analyses of 219 male plants belonging to 12 populations showed across a wide geographical range one quadrivalent and seven bivalents in all of them. The quadrivalent involves the four biggest m chromosomes and probably constitutes a sex multivalent carrying in tight linkage the sex genes and provides a mechanism whereby permanent translocation heterozygosity is maintained. In metaphase I alternate orientation of the quadrivalent was predominant (85.71 %). Fourteen megaspore mother cells were analyzed and did not show the quadrivalent. A model for the origin and maintenance of the sexual translocation system is presented. It is assumed that there are two non-allelic factors M and n; M would be a dominant female suppresor and n a recessive male-suppresor. The excess of male plants observed in several populations at different localities might result from heterotic effects of some gene complexes carried by the translocation. This excess probably ensures a good supply of pollen for the vagaries of insect pollination at flowering time. Fil:Wulff, A.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v137_n2_p132_Hunziker http://hdl.handle.net/20.500.12110/paper_00180661_v137_n2_p132_Hunziker
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic allele
article
Asteraceae
centromere
chromosome
chromosome bivalent
chromosome translocation
controlled study
diploidy
dominant gene
flowering
genetic linkage
geographic distribution
heterozygosity
karyotype
meiosis
metaphase
nonhuman
plant insect interaction
pollen
pollen mother cell
pollination
population genetics
recessive gene
sex ratio
suppressor gene
Asteraceae
Chromosomes, Plant
Heterozygote
Translocation, Genetic
Asteraceae
Baccharis
Embryophyta
Insecta
spellingShingle allele
article
Asteraceae
centromere
chromosome
chromosome bivalent
chromosome translocation
controlled study
diploidy
dominant gene
flowering
genetic linkage
geographic distribution
heterozygosity
karyotype
meiosis
metaphase
nonhuman
plant insect interaction
pollen
pollen mother cell
pollination
population genetics
recessive gene
sex ratio
suppressor gene
Asteraceae
Chromosomes, Plant
Heterozygote
Translocation, Genetic
Asteraceae
Baccharis
Embryophyta
Insecta
Wulff, Arturo Federico
Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
topic_facet allele
article
Asteraceae
centromere
chromosome
chromosome bivalent
chromosome translocation
controlled study
diploidy
dominant gene
flowering
genetic linkage
geographic distribution
heterozygosity
karyotype
meiosis
metaphase
nonhuman
plant insect interaction
pollen
pollen mother cell
pollination
population genetics
recessive gene
sex ratio
suppressor gene
Asteraceae
Chromosomes, Plant
Heterozygote
Translocation, Genetic
Asteraceae
Baccharis
Embryophyta
Insecta
description The karyotype of Baccharis coridifolia DC., a dioecious diploid species consists of 16 chromosomes with median (m) and 2 with submedian centromeric positions (sm) (2n = 18). Meiotic analyses of 219 male plants belonging to 12 populations showed across a wide geographical range one quadrivalent and seven bivalents in all of them. The quadrivalent involves the four biggest m chromosomes and probably constitutes a sex multivalent carrying in tight linkage the sex genes and provides a mechanism whereby permanent translocation heterozygosity is maintained. In metaphase I alternate orientation of the quadrivalent was predominant (85.71 %). Fourteen megaspore mother cells were analyzed and did not show the quadrivalent. A model for the origin and maintenance of the sexual translocation system is presented. It is assumed that there are two non-allelic factors M and n; M would be a dominant female suppresor and n a recessive male-suppresor. The excess of male plants observed in several populations at different localities might result from heterotic effects of some gene complexes carried by the translocation. This excess probably ensures a good supply of pollen for the vagaries of insect pollination at flowering time.
author Wulff, Arturo Federico
author_facet Wulff, Arturo Federico
author_sort Wulff, Arturo Federico
title Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
title_short Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
title_full Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
title_fullStr Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
title_full_unstemmed Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae)
title_sort permanent translocation heterozygosity in dioecious baccharis coridifolia dc. (asteraceae)
publishDate 2002
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00180661_v137_n2_p132_Hunziker
http://hdl.handle.net/20.500.12110/paper_00180661_v137_n2_p132_Hunziker
work_keys_str_mv AT wulffarturofederico permanenttranslocationheterozygosityindioeciousbacchariscoridifoliadcasteraceae
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