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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todo:paper_00180661_v137_n2_p132_Hunziker2023-10-03T14:15:17Z Permanent translocation heterozygosity in dioecious Baccharis coridifolia DC. (Asteraceae) Hunziker, J.H. Wulff, A.F. Escobar, A. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00180661_v137_n2_p132_Hunziker |
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Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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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 Hunziker, J.H. Wulff, A.F. Escobar, A. 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. |
| format |
JOUR |
| author |
Hunziker, J.H. Wulff, A.F. Escobar, A. |
| author_facet |
Hunziker, J.H. Wulff, A.F. Escobar, A. |
| author_sort |
Hunziker, J.H. |
| 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) |
| url |
http://hdl.handle.net/20.500.12110/paper_00180661_v137_n2_p132_Hunziker |
| work_keys_str_mv |
AT hunzikerjh permanenttranslocationheterozygosityindioeciousbacchariscoridifoliadcasteraceae AT wulffaf permanenttranslocationheterozygosityindioeciousbacchariscoridifoliadcasteraceae AT escobara permanenttranslocationheterozygosityindioeciousbacchariscoridifoliadcasteraceae |
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1807317963458478080 |