B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation
Cytogenetic analysis of maize landraces from northwestern Argentina has revealed an altitudinal cline in the mean number of B chromosomes (B's) per plant, with cultivars growing at higher altitudes exhibiting a higher number of B's. Altitudinal and longitudinal clines are frequently interp...
Guardado en:
| Publicado: |
2007
|
|---|---|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166731_v177_n2_p895_Lia http://hdl.handle.net/20.500.12110/paper_00166731_v177_n2_p895_Lia |
| Aporte de: |
| id |
paper:paper_00166731_v177_n2_p895_Lia |
|---|---|
| record_format |
dspace |
| spelling |
paper:paper_00166731_v177_n2_p895_Lia2025-07-30T17:21:19Z B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation adaptation article autosome chromosome analysis climate controlled study demography gene flow gene locus genetic association genetic polymorphism genetic selection genetic variability maize nonhuman population structure priority journal simple sequence repeat Adaptation, Physiological Argentina Biometry Chromosomes, Plant Polymorphism, Genetic Zea mays Zea mays Cytogenetic analysis of maize landraces from northwestern Argentina has revealed an altitudinal cline in the mean number of B chromosomes (B's) per plant, with cultivars growing at higher altitudes exhibiting a higher number of B's. Altitudinal and longitudinal clines are frequently interpreted as evidence of selection, however, they can also be produced by the interplay between drift and spatially restricted gene flow or by admixture between previously isolated populations that have come into secondary contact. Here, we test the adaptive significance of the observed altitudinal gradient by comparing the levels of differentiation in the mean number of B's to those obtained from 18 selectively neutral loci [simple sequence repeats (SSRs)] among seven populations of the cline. The adequacy of alternative genetic-differentiation measures was determined, and associations between cytogenetic, genetic, and altitudinal distances were assessed by means of matrix- correspondence tests. No evidence for association between pairwise FST and altitudinal distance or B-chromosome differentiation was found. The contrasting pattern of altitudinal divergence between the mean number of B's per plant and the genetic differentiation at SSR loci indicates that demographic processes cannot account for the observed levels of divergence in the mean number of B's. Copyright © 2007 by the Genetics Society of America. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166731_v177_n2_p895_Lia http://hdl.handle.net/20.500.12110/paper_00166731_v177_n2_p895_Lia |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
adaptation article autosome chromosome analysis climate controlled study demography gene flow gene locus genetic association genetic polymorphism genetic selection genetic variability maize nonhuman population structure priority journal simple sequence repeat Adaptation, Physiological Argentina Biometry Chromosomes, Plant Polymorphism, Genetic Zea mays Zea mays |
| spellingShingle |
adaptation article autosome chromosome analysis climate controlled study demography gene flow gene locus genetic association genetic polymorphism genetic selection genetic variability maize nonhuman population structure priority journal simple sequence repeat Adaptation, Physiological Argentina Biometry Chromosomes, Plant Polymorphism, Genetic Zea mays Zea mays B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| topic_facet |
adaptation article autosome chromosome analysis climate controlled study demography gene flow gene locus genetic association genetic polymorphism genetic selection genetic variability maize nonhuman population structure priority journal simple sequence repeat Adaptation, Physiological Argentina Biometry Chromosomes, Plant Polymorphism, Genetic Zea mays Zea mays |
| description |
Cytogenetic analysis of maize landraces from northwestern Argentina has revealed an altitudinal cline in the mean number of B chromosomes (B's) per plant, with cultivars growing at higher altitudes exhibiting a higher number of B's. Altitudinal and longitudinal clines are frequently interpreted as evidence of selection, however, they can also be produced by the interplay between drift and spatially restricted gene flow or by admixture between previously isolated populations that have come into secondary contact. Here, we test the adaptive significance of the observed altitudinal gradient by comparing the levels of differentiation in the mean number of B's to those obtained from 18 selectively neutral loci [simple sequence repeats (SSRs)] among seven populations of the cline. The adequacy of alternative genetic-differentiation measures was determined, and associations between cytogenetic, genetic, and altitudinal distances were assessed by means of matrix- correspondence tests. No evidence for association between pairwise FST and altitudinal distance or B-chromosome differentiation was found. The contrasting pattern of altitudinal divergence between the mean number of B's per plant and the genetic differentiation at SSR loci indicates that demographic processes cannot account for the observed levels of divergence in the mean number of B's. Copyright © 2007 by the Genetics Society of America. |
| title |
B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| title_short |
B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| title_full |
B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| title_fullStr |
B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| title_full_unstemmed |
B chromosome polymorphism in maize landraces: Adaptive vs. demographic hypothesis of clinal variation |
| title_sort |
b chromosome polymorphism in maize landraces: adaptive vs. demographic hypothesis of clinal variation |
| publishDate |
2007 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00166731_v177_n2_p895_Lia http://hdl.handle.net/20.500.12110/paper_00166731_v177_n2_p895_Lia |
| _version_ |
1840325916417327104 |