Fluorescence in situ hybridization with centromeric, telomeric and whole chromosome paint probes was used to study nuclear topology in epididymal sperm as well as spermatids from testis tissue sections of the rat. Pericentromeric regions of 9 chromosomes of the rat (n=21) were labeled with a satellite I specific DNA probe. Pericentromeres showed few tandem associations in spermatids of steps 1-...

In order to facilitate the map-based cloning of the barley stem rust resistance gene Rpg1, we have demonstrated a high degree of synteny at a micro level between the telomeric region of barley chromosome 1P and rice chromosome 6. We have also developed and applied a simple and efficient method for selecting useful probes from large insert genomic YAC and cosmid clones. The gene order within the...

The aim of the present study has been the evaluation of the incompleteness of αparticle induced chromosome aberrations by the simultaneous detection of all centromeres and telomeres present in human lymphocytes. For this purpose attached lymphocytes were irradiated at doses of 0.2, 0.5, 0.7 and 1 Gy in a Am source. FISH techniques were applied using pan-centromeric and pan-telomeric probes. All...

Oligoryzomys belongs to the tribe Oryzomyini, and contains about 22 species. Diploid numbers range from 2n = 44 in Oligoryzomys sp. 2 to 2n = 72 in O. utiaritensis and phylogenetic relationships are not well defined. The high morphological convergence leads to misidentification of taxonomic entities and the species are often identified by chromosomal characters. Until now, the genus has been st...

Mental retardation (MR), defined as an intelligence quotient (IQ) of less than 70, affects 2-3% of the population and its aetiology and pathogenesis are still poorly understood. The aetiology can be established in only ~64% of cases with moderate to profound MR and in ~24% of cases with mild MR. Available data indicate that chromosome aberrations are found in 4-28% of affected subjects. However...

We have identified a rice gene encoding a DNA-binding protein that specifically recognizes the telomeric repeat sequence TTTAGGG found in plants. This gene, which we refer to as RTBP1 (rice telomere-binding protein 1), encodes a polypeptide with a predicted molecular mass of 70 kDa. RTBP1 is ubiquitously expressed in various organs and binds DNA with two or more duplex TTTAGGG repeats. The pred...

Chromosome counts and karyotype characterization have proved to be important features of a genome. Chromosome changes during the diversification of ants might play an important role, given the diversity and success of Formicidae. Comparative karyotype analyses on ants have enriched and helped ant systematics. Among leafcutter ants, two major chromosome counts have been described, one frequent i...

Polyploidization has played an important role in the evolution of vertebrates, particularly at the base of Teleostei-an enormously successful ray-finned fish group with additional genome doublings on lower taxonomic levels. The investigation of post-polyploid genome dynamics might provide important clues about the evolution and ecology of respective species and can help to decipher the role of ...

The Iguazu river is a tributary of the left margin of the Paraná river, isolated from this basin about 22 million years ago with the appearance of the Iguazu Falls. The Iguazu river is characterized by high endemism due to two factors: its rugged topography and the old isolation caused by formation of the Iguazu Falls. This study analyzed cytogenetically a population of Glanidium ribeiroi colle...

The family Mactridae is composed of a diverse group of marine organisms, commonly known as trough shells or surf clams, which illustrate a global distribution. Although this family includes some of the most fished and cultured bivalve species, their chromosomes are poorly studied. In this work, we analyzed the chromosomes of Spisula solida, Spisula subtruncata and Mactra stultorum by means of f...