Clinical isolates of the fungal human pathogen Candida albicans are invariably diploid and heterozygous, impeding genetic study. Recent isolation of C. albicans haploids opens opportunities to apply technologies unfeasible in diploids. However, doubts remain on whether the haploids, derived from chromosome loss, can represent the diploids. Here, we use C. albicans haploids to investigate biofil...

Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, gamma-ray-induced, UV-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative mediu...

The purpose of this study was to determine whether triploid salmonid fishes differ from diploids in their hematological and physiological responses to an acute handling and confinement stress, induced by netting fish from their tanks and placing them in a bucket. Blood samples were Ž . collected from fish prior to the handling stress and at either 30 min rainbow trout or 20 and 40 Ž . min brook...

Detailed ecological, morphological and molecular analyses were performed in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. in Scandinavia. Comparisons were made with pure populations of either diploid ssp. fuchsii or tetraploid ssp. maculata. It was shown that mixed populations are the result of secondary contact between ssp. fuchsii and ssp. maculata. No patterns of...

In this short review we report the basic notions needed for understanding the population genetics of clonal diploids. We focus on the consequences of clonality on the distribution of genetic diversity within individuals, between individuals and between populations. We then summarise how to detect clonality in mainly sexual populations, conversely, how to detect sexuality in mainly clonal popula...

Forty-eight useful new mutations of S. commune were obtained by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Their requirements and meiotic linkage relationships to each other and previously mapped areas were investigated. Several of these new mutations were incorporated into diploid strains so that the diploids contained at least one marker on every linkage group. Analysis of somatic...

The evolutionary genetics of haplodiploids and X-linked genes share many features and are different from diploid (autosomal) genes in many respects. For example, the conditions for a stable polymorphism, the amount of genetic load, and the effective population size are all expected to be quite different between haplodiploids or X-linked genes and diploids. From experimental data, the genetic lo...

Origin of sperm with extra chromosome set Dear Sir, We read with interest the article by Devillard et al. (2002), in which they report on the high frequency of various polyploidies in large-headed sperm. Examining sperm nuclei by FISH from three patients with macrocephalic, multi¯agellated sperm, they also concluded that incomplete partition of homologous chromosomes/chromatids during both meio...

The Asplenium obovatum group consists of diploid and tetraploid taxa; the origin of the tetraploid A. obovatum subsp. lanceolatum was previously considered to have occurred via autopolyploidy, involving one of the diploids of the group, either A. obovatum subsp. obovatum var. obovatum or var. protobillotii. To test this hypothesis, electrophoretic analyses of eight enzyme systems encoded by fou...