INVESTIGADORES
SEIJO Jose Guillermo
artículos
Título:
Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae): -.
Autor/es:
CHALUP, L.; GRABIELE M; SOLÍS NEFFA, V.G.; SEIJO, J.G
Revista:
PLANT SYSTEMATICS AND EVOLUTION
Editorial:
SPRINGER WIEN
Referencias:
Lugar: Viena; Año: 2012 vol. 298 p. 761 - 773
ISSN:
0378-2697
Resumen:
Abstract Knowledge of the chromosome variation in
wild populations is essential to understand the pathways
and restrictions of karyotype evolution in plants. The aim
of this study is to conduct an intraspecific analysis of the
karyotypes by fluorochrome banding and ribosomal DNA
(rDNA) loci detection by fluorescent in situ hybridization
(FISH) and of the meiotic behaviour in natural populations
of Lathyrus nervosus, sect. Notolathyrus. Chromosome
banding showed that, despite the high constancy in the
karyotype formula and in the rDNA loci among populations,
there is intraspecific variation in the amount and
distribution pattern of 4?,6-diamidino-2-phenylindole
(DAPI?) heterochromatin. However, those changes were
not related to the total chromosome length of the haploid
complements. This fact demonstrates that structural chromosome
changes may be one of the most important
mechanisms for karyotype variation among natural populations
of L. nervosus. The chromosome number surveyed
at the population level revealed the first case of polyploidy
in South American species and the first case of uneven
polyploidy of the genus. All the chromosome markers
analysed indicated that the polyploids found originated by
autopolyploidy. The meiotic analysis showed different
chromosome abnormalities that may be generating
numerical and structural changes in the sporads. The
finding of unreduced gametes that are alive at anthesis
suggests sexual polyploidization as the most probable
mechanism involved in the origin of these 3x and 4x autopolyploid
cytotypes in L. nervosus.