Search results for "Diploidy"
showing 10 items of 36 documents
High and uneven levels of 45S rDNA site-number variation across wild populations of a diploid plant genus (Anacyclus, Asteraceae)
2017
The nuclear genome harbours hundreds to several thousand copies of ribosomal DNA. Despite their essential role in cellular ribogenesis few studies have addressed intrapopulation, interpopulation and interspecific levels of rDNA variability in wild plants. Some studies have assessed the extent of rDNA variation at the sequence and copy-number level with large sampling in several species. However, comparable studies on rDNA site number variation in plants, assessed with extensive hierarchical sampling at several levels (individuals, populations, species) are lacking. In exploring the possible causes for ribosomal loci dynamism, we have used the diploid genus Anacyclus (Asteraceae) as a suitab…
An integrated proteomic and metabolomic study to evaluate the effect of nucleus-cytoplasm interaction in a diploid citrus cybrid between sweet orange…
2018
Key message: Our results provide a comprehensive overview how the alloplasmic condition might lead to a significant improvement in citrus plant breeding, developing varieties more adaptable to a wide range of conditions. Abstract: Citrus cybrids resulting from somatic hybridization hold great potential in plant improvement. They represent effective products resulting from the transfer of organelle-encoded traits into cultivated varieties. In these cases, the plant coordinated array of physiological, biochemical, and molecular functions remains the result of integration among different signals, which derive from the compartmentalized genomes of nucleus, plastids and mitochondria. To dissect …
Sex ratio and sexual conflict in a collective action problem
2020
AbstractThe maintenance of cooperation is difficult whenever collective action problems are vulnerable to freeriding (reaping the benefits without contributing to the maintenance of the good). We identify a novel factor that can make a system tolerate an extent of freeriding. If a population consists of discrete types with demographically distinct roles, such that the success of one type does not imply it can spread to replace other types in the population, then collective goods may persist in the presence of free-riders because they are necessarily kept in a minority role. Biased sex ratios (e.g. in haplodiploids) create conditions where individuals of one sex are a minority. We show that …
Extended haplodiploidy hypothesis
2019
P.R., M.P., and H.H. were supported by Academy of Finland (grant 258385 to M.P., grant 135970 to H.H., and 252411 to the Centre of Excellence in Biological Interactions), P.R. also by the Royal Society Newton International Fellowship, and H.H. also by the Kone Foundation. Evolution of altruistic behavior was a hurdle for the logic of Darwinian evolution. Soon after Hamilton formalized the concept of inclusive fitness, which explains how altruism can evolve, he suggested that the high sororal relatedness brought by haplodiploidy could be why Hymenopterans have a high prevalence in eusocial species, and why helpers in Hymenoptera are always female. Later it was noted that in order to capitali…
Effects of inbreeding on a gregarious parasitoid wasp with complementary sex determination
2017
Inbreeding and inbreeding depression are processes in small populations of particular interest for a range of human activities such as animal breeding, species conservation or pest management. In particular, biological control programs should benefit from a thorough understanding of the causes and consequences of inbreeding because natural enemies experience repetitive bottlenecks during importation, laboratory rearing, and introduction. Predicting the effect of inbreeding in Hymenopteran parasitoid wasps, frequently used in biological control programs, is nonetheless a difficult endeavor. In haplodiploid parasitoids, the purge of deleterious alleles via haploid males should reduce genetic …
The evolutionary dynamics of adaptive virginity, sex-allocation, and altruistic helping in haplodiploid animals
2017
In haplodiploids, females can produce sons from unfertilized eggs without mating. However, virgin reproduction is usually considered to be a result of a failure to mate, rather than an adaptation. Here, we build an analytical model for evolution of virgin reproduction, sex-allocation, and altruistic female helping in haplodiploid taxa. We show that when mating is costly (e.g., when mating increases predation risk), virginity can evolve as an adaptive female reproductive strategy. Furthermore, adaptive virginity results in strongly divergent sex-ratios in mated and virgin queen nests ("split sex ratios"), which promotes the evolution of altruistic helping by daughters in mated queen nests. H…
Evaluation of DNA ploidy and degree of DNA abnormality in benign and malignant melanocytic lesions of the skin using video imaging.
2000
BACKGROUND Making a morphologic distinction between benign and malignant melanocytic tumors of the skin is frequently difficult, especially because “gray zones” between these lesions often exist. DNA image cytometry as an adjuvant method for the diagnosis and prognostic prediction of premalignant lesions and malignant tumors of many other organs is already well established. The aim of this study was to determine whether DNA image cytometry is helpful in distinguishing benign from malignant melanocytic lesions and whether cytometry would give valid information with which to predict the prognoses associated with malignant melanomas. METHODS DNA image cytometry was performed on 127 benign and …
Flow cytometric DNA analysis of hepatic tumours on ultrasound-guided fine-needle aspirates
1992
A study was performed on a nonconsecutive series of 51 patients in order to assess the feasibility, reliability, and usefulness of flow cytometric (FCM) DNA analysis of samples obtained from benign and malignant hepatic tumours by means of ultrasound-guided fine-needle aspiration (UG-FNA). Cytological and often histological confirmation of the nature of the lesion was obtained in all cases from an expert pathologist. For FCM DNA analysis in 32 cases, it was also possible to use samples obtained at surgery from the actual tumours. There were no post UG-FNA complications, either early or late. It was possible to perform FCM DNA analysis on 6/7 (85.7%) of the benign tumour aspirates and all 44…
Testicular sperm from patients with obstructive and nonobstructive azoospermia: aneuploidy risk and reproductive prognosis using testicular sperm fro…
2010
Objective To establish a baseline incidence of chromosomal abnormalities in testicular sperm of fertile men and to determine the best control sample for comparisons with azoospermic males to estimate their reproductive prognosis. Design Prospective study. Setting Infertility clinic. Patient(s) Sixteen obstructive azoospermic (OA) and 19 nonobstructive azoospermic patients (NOA). Control samples were ejaculated sperm from ten fertile donors and testicular sperm from ten other fertile donors. Intervention(s) Fluorescence in situ hybridization (FISH) in sperm. Main Outcome Measure(s) Sperm numerical abnormalities for chromosomes 13, 18, 21, X, and Y; ongoing implantation and pregnancy rates in…
Differences in the mechanisms of growth control in contact-inhibited and serum-deprived human fibroblasts
1997
In the present work we studied mechanisms of growth control in contact-inhibited and serum-deprived human diploid fibroblasts. The observation that the effects on [3H]thymidine incorporation and reduction of retinoblastoma gene product-phosphorylation were additive when contact-inhibition and serum-deprivation were combined led us to the conclusion that the underlying mechanisms might be different. Both contact-inhibition and serum-deprivation led to a strong decrease of cdk4-kinase-activity and cdk2-phosphorylation at Thr 160, while the total amounts of cdk4 and cdk2 remained constant. In contact-inhibited cells, we revealed a strong protein accumulation of the cdk2-inhibitor p27 and a sli…