Chromosome cytology was examined in two species of the Aster ageratoides complex, A. ageratoides Turcz. (= A. leiophyllus Franch. et Sav.) and A. lasioclada Hayata, in Taiwan. Of the 70 individuals of A. ageratoides sampled, one was found to be diploid (2n = 18) and the rest tetraploid (2n = 36, 37). The occurrence of the diploid A. ageratoides in Taiwan appears to be ancient. Eighteen individu...

The linkage of two mutations leading to increased sensitivity to ultraviolet light and 60Co gamma rays was determined in the slime mould Dictyostelium discoideum using a genetic analysis based on the parasexual cycle. Diploids were selected from a mixture of radiation-sensitive, temperature-resistant and radiation-resistant, temperature-sensitive haploids on the basis of simultaneous radiation ...

Entry into meiosis is a key developmental decision. We show here that meiotic entry in Saccharomyces cerevisiae is controlled by antisense-mediated regulation of IME4, a gene required for initiating meiosis. In MAT a/alpha diploids the antisense IME4 transcript is repressed by binding of the a1/alpha2 heterodimer at a conserved site located downstream of the IME4 coding sequence. MAT a/alpha di...

Abstract Given molecular genetic data from diploid individuals that, at present, reproduce mostly or exclusively asexually without recombination, an important problem in evolutionary biology is detecting evidence of past sexual reproduction (i.e., meiosis and mating) and recombination (both meiotic and mitotic). However, currently there is a lack of computational tools for carrying out such a s...

Environmental niche modelling and associated species distribution models often ignore intraspecific ecological differentiation linked with ploidal differentiation, i.e. the occurrence of several cytotypes same species. Here we tested hypotheses that (i) tetraploid (4x) cytotype is characterized by a broader than diploid (2x), (ii) at regional scale can serve as proxy measure for smaller landsca...

BACKGROUND The common stinging nettle, Urtica dioica L. sensu lato, is an invertebrate "superhost", its clonal patches maintaining large populations of insects and molluscs. It is extremely widespread in Europe and highly variable, and two ploidy levels (diploid and tetraploid) are known. However, geographical patterns in cytotype variation require further study. NEW INFORMATION We assembled ...

Adaptation in diploids is predicted to proceed via mutations that are at least partially dominant in fitness. Recently we argued that many adaptive mutations might also be commonly overdominant in fitness. Natural (directional) selection acting on overdominant mutations should drive them into the population but then, instead of bringing them to fixation, should maintain them as balanced polymor...

The seedling traits is a simple and non-destructive methodology used to identify haploids/diploids in maize. This study aimed at establishing an optimal germination temperature evaluate this verify its effectiveness. Haploid diploid seeds, obtained from crosses with the haploidy inducer TAIL9, were classified using R1-Navajo marker placed germinated growth chambers maintained different temperat...

Trifluoroleucine-resistant yeast mutants with an end-product-insensitive alpha-isopropylmalate synthetase are dominant in diploids. This property provides a simple screen for their detection.