INVESTIGADORES
MARTI Dardo Andrea
artículos
Título:
A heterozygous paracentric inversion only detectable through Electron Microscopy, in the grasshopper Dichroplus pratensis (Melanoplinae, Acrididae)
Autor/es:
DARDO ANDREA MARTI AND CLAUDIO JUAN BIDAU
Revista:
CARYOLOGIA
Editorial:
Natural History Museum, University of Firenze
Referencias:
Lugar: Firenze; Año: 2003 p. 171 - 176
ISSN:
0008-7114
Resumen:
Abstract:
In this
paper we describe a spontaneous heterozygous paracentric inversion in
telocentric chromosome L2 of a Dichroplus pratensis male from a natural population
of Argentina.
This male was also heterozygous for two Robertsonian translocations. The
inversion was only detected through transmission electron microscopy of
synaptonemal complexes because in some pachytene nuclei a reverse loop was
formed and the region distal to it remained unsynapsed. However, in other more
advanced pachytene spermatocytes, nonhomologous (straight) pairing, was
observed. Instead, analysis of the inversion mutant by light microscopy failed
to reveal any pairing abnormalities except for a very low frequency of distal
asynapsis of the L2 bivalent. Furthermore, no bridge and fragment
configurations were observed nor any other abnormalities during the course of
meiosis or the development of spermatids, that could indicate the presence of
the inversion. The inversion also causes a significant repatterning of
chiasmata in the L2 bivalent which could be due to heterosynapsis and/or
desynapsis of the involved region. This could explain the absence of crossing
over within the inverted region and thus, of aberrant recombinant chromatids. The
relationship between paracentric inversions and Robertsonian translocations in
D. pratensis, is discussed.