Release-recapture experiments using Drosophila pseudoobscura and D. persimilis strains of different karyotypes were performed in a heterogeneous environment. The heterogeneity was due to both spatial variation and the species of yeast used to attract the released flies. No karyotypic-specific habitat preferences were detected. However, in all releases, different strains did behave differently w...

Among catfish species of the genus Rhamdia reported for the Brazilian territory, R. quelen is the most widespread, being found in nearly all hydrographic basins of Brazil. Nowadays, R. quelen is a synonym for at least 47 other species in this genus, its taxonomic status still being controversial. The available cytogenetic reports show a wide variation in the karyotypic macrostructure, with the ...

Most models of speciation require gradual change and geographic or ecological isolation for new species to arise. Homoploid hybrid speciation occurred readily between Saccharomyces cerevisiae and Saccharomyces paradoxus. Hybrids had high self-fertility (about 82%), low fertility when backcrossed to either parental species (about 7.5%), and vigorous growth under different thermal environments th...

Since cancers have individual clonal karyotypes, are immortal and evolve from normal cells treated by carcinogens only after exceedingly long latencies of many months to decades-we deduce that carcinogenesis may be a form of speciation. This theory proposes that carcinogens initiate carcinogenesis by causing aneuploidy, i.e., losses or gains of chromosomes. Aneuploidy destabilizes the karyotype...

BACKGROUND AND AIMS Investigating intraspecific karyotypic and genetic variations jointly can provide unique insights into how historical, ecological and cytogenetic factors influence microevolution. A coastal herb, Lysimachia mauritiana, exhibits extensive karyotypic polymorphism and displays a complex cytogeographic pattern across the Ryukyus. To explore whether a similar degree of chromosoma...

ABSTRACT: Cytotaxonomy is useful for separating sister and cryptic species as well figuring out the evolutionary relationship between taxa. Family Coenagrionidae considered one of largest zygopteran families under order Odonata. Globally, a lot investigation has been undertaken on family significantly contributed by biologists throughout world. Type number n=14 with XO-XX type sex determining m...

Seventy-one isolines of Anopheles campestris-like were established from wild-caught females collected from human-biting and animal-biting traps at 12 locations in Thailand. All isolines had an average branch summation of seta 2-VI pupal skins ranging from 20.3-30.0 branches, which is in the range of An. campestris (17-58 branches). They showed three different karyotypes based on the amount of e...