European Journal of Entomology

In Mormidea paupercula (n = 6 + XY in males), the presence of a CMA₃-bright band in the telomeric regions on both sex chromosomes allowed the analysis of the kinetic activity of the sex univalents and XY pseudobivalent at the first and second meiotic divisions, respectively. The separation of the sister chromatids of the sex chromosomes occurs from a pair of telomeric regions (with or without a band), with opposite telomeric regions remaining associated with each other at meiosis I; the behaviour of both sex chromosomes differs, on the X chromosome both telomeric regions are similarly active, while on the Y chromosome the telomeric region without a band is more frequently active. At the second division, the most frequent associations in the pseudobivalent occur between the telomeric regions of both sex chromosomes with bands or without bands. Therefore, in both meiotic divisions, the same telomeric region on the sex chromosomes could lead the migration, in contrast to that observed usually in autosomal bivalents. These results provide evidence that the sex chromosomes of Heteroptera show more than one pattern of attachment to the spindle.

Address
Laboratorio de Citogenética y Evolución, Departamento de Ecología Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes y Costanera Norte, 1428 Ciudad Universitaria, Ciudad Autónoma de Buenos Aires, Argentina; e-mails: gchu@ege.fcen.uba.ar, limola@ege.fcen.uba.ar

Keywords
Heteroptera, Pentatomidae, sex chromosomes, kinetic activity, holokinetic chromosomes, meiosis, Mormidea