Protein markers of synaptic behavior and chromatin remodeling of the neo-XY body in phyllostomid bats.

The XX/XY system is the rule among mammals. However, many exceptions from this general pattern have been discovered since the last decades. One of these non-conventional sex chromosome mechanisms is the multiple sex chromosome system, which is evolutionary fixed among many bat species of the family Phyllostomidae, and has arisen by a translocation between one original gonosome (X or Y chromosome), and an autosome, giving rise to a "neo-XY body.

Synapsis, recombination, and chromatin remodeling in the XY body of armadillos.

Three xenarthrans species Chaetophractus villosus, Chaetophractus vellerosus, and Zaedyus pichiy have been used for the analysis of the structure, behavior, and immunochemical features of the XY body during pachytene. In all these species, the sex chromosomes form an XY body easily identifiable in thin sections by the special and regular packing of the chromatin fibers of the internal region of the XY body ("differential" regions) and those of the peripheral region (synaptic region). Spermatocyte spreads show a complete synapsis between the X- and the Y-axis, which lasts up to the end of pachytene.

Phylogenetic relationships among some Ateles species: the use of chromosomic and molecular characters.

As with most platyrrhines, the systematics of Ateles is under discussion. In order to help clarify its systematic, we employed chromosomic and molecular characters to analyze the phylogenetic relationship among some species of the genus Ateles. Chromosomic studies were conducted on 14 atelid specimens: eight Ateles from A.

A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope.

The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge.