INVESTIGADORES
CONFALONIERI Viviana Andrea
artículos
Título:
Cytogeography and the evolutionary significance of B-chromosomes in relation to inverted rearrangements in a grasshoper species
Autor/es:
34. COLOMBO,P. & CONFALONIERI, V.A.
Revista:
CYTOGENETIC AND GENOME RESEARCH
Editorial:
Karger
Referencias:
Lugar: Basel; Año: 2004 vol. 106 p. 351 - 358
ISSN:
1424–8581
Resumen:
The analysis of geographic distribution of polymorphic
cytological markers, briefly termed as cytogeography,
can be considered an important tool to be applied when
studying the evolutionary significance of chromosome variability
within a species, either to unravel the adaptive significance
of chromosome polymorphisms or to investigate the parasitic
nature of some genomic elements. In this article we review
cytogeographical studies in Trimerotropis pallidipennis, a grasshopper
species whose South American populations display geographical
patterns of distribution of inversion and B chromosome
polymorphisms. Several lines of evidence that issue from
the analysis of the geographic distribution of polymorphic
markers suggest that inverted chromosomes are special sequences
that are maintained by deterministic forces. On the
other hand, the pattern of distribution of B chromosome polymorphism
clearly demonstrates its selfish nature, being more
frequent in those populations in central environments. We also
present the analysis of 272 individuals of T. pallidipennis from
Uspallata, and demonstrate that Bs in this population have
some influence on body size, enlarging many of the morphometric
characters of individuals and we propose it could be the
consequence of its genotypic disequilibrium with one inversion.
These investigations are finally discussed with regard to
the models proposed for the maintenance of B chromosomes in
natural populations and in relation to the possible interactions
with chromosome inversions.