The importance of the chromosome versus the gene as a causative agent in cancer formation has sparked a heated debate. This issue is directly related to two different schools of thought, namely the gene-centric or genome-centric paradigms of cancer research [1–3]. For decades we have essentially ignored the evolutionary nature of complex cancer systems due to the influence of reductionist viewp...

In the present study the karyotypes and the number and position of nucleolus organizer regions (NORs) of four species of Characiformes are described. The analyses showed that Acestrorhynchus lacustris had 2n=50 chromosomes (8M+34SM+6ST+2A), Oligosarcus longirostris had 2n=50 chromosomes (2M+20SM+10ST+18A), Oligosarcus cf. paranensis from Keller and Mourão rivers had 2n=50 chromosomes (2M+26SM+8...

The karyotypes of three species of fish of the Cichlidae family from the Forqueta river and several locations in Guaiba lake/RS (Brazil) were analyzed. All species presented 2n=48, while Gymnogeophagus gymnogenys showed two karyotypic formulae: 4m+44st-a with FN=52 and 6m+42st-a with FN=54. Gymnogeophagus labiatus presented 4m+4sm+40st-a and FN=56 and Geophagus brasiliensis 4sm+44st-a and FN=52...

A checklist based approach to reporting the relevant pathologic details of renal cell carcinoma resection specimens improves the completeness of the report. Karyotypic evaluation of renal neoplasms has refined but also complicated their classification. The number of diagnostic possibilities has increased and the importance of distinguishing different tumor types has been underscored by dramatic...

The tendency toward chromosome fragility is one of the theories that may explain chromosome variation in brocket deer species (genus Mazama). We tested doxorubicin as an inducer of chromosome aberrations in lymphocytes of three brocket deer species, Mazama gouazoubira, M. americana and M. nana, compared to the marsh deer, Blastocerus dichotomus. Doxorubicin, at a concentration of 0.25 microg/mL...

Drosophila meridionalis is a cactus-breeding species with a wide distribution in South America. Most populations of this species are geographically isolated, what provides a promising scenario for studying evolution. Former studies of this species revealed a remarkable karyotypic variation among its populations. Up to six distinct metaphase chromosomes were described, showing that this species ...

Belostoma, a genus of the family Belostomatidae, includes species of great ecological importance as biocontrol agents. Few species of these species have been the subject of cytogenetic analyses. Karyotypic evolution in this genus involves agmatoploidy and simploidy; there are also different sex chromosome systems. We examined two Belostoma species (B. dilatatum and B. candidulum) collected from...

According to the nearly-neutral model, variation in long-term effective population size among species should result in correlated variation in the ratio of nonsynonymous over synonymous substitution rates (dN/dS). Previous empirical investigations in mammals have been consistent with this prediction, suggesting an important role for nearly-neutral effects on protein-coding sequence evolution. G...

INTRODUCTION A case of premature ovarian failure with concomitant findings of Robertsonian translocation between 15 and 21 chromosomes is reported here. The aforementioned karyotypic aberration has not been reported in the context of premature ovarian failure to date. CASE PRESENTATION We present a case of premature ovarian failure in a 27-year-old infertile Kurdish Iranian woman with a Rober...