Interspecific hybrid lethality and sterility are a consequence of divergent evolution between species and serve to maintain the discrete identities of species. The evolution of hybrid incompatibilities has been described in widely accepted models by Dobzhansky and Muller where lineage-specific functional divergence is the essential characteristic of hybrid incompatibility genes. Experimentally ...

Wolbachia are bacteria that live inside the cells of a large number of invertebrate hosts and are transmitted from infected females to their offspring. Their presence is associated with cytoplasmic incompatibility in several species of Drosophila. Cytoplasmic incompatibility results when the sperm of infected males fertilize eggs of uninfected females, causing more or less intense embryonic mor...

A quantitative model is developed to explore the effects of prezygotic and postzygotic incompatibility on the origin and maintenance of associations between the major histocompatibility complex (MHC) and the t-complex in the mouse. Incompatibility is represented by a reduction in the rate of conception or gestation of offspring derived from sperm bearing MHC antigens in common with the mother. ...

Pragmatic definitions of material incompatibility and two kinds of consequence: • Incompatibility of p and q: If S is committed to p, then S is not entitled to q. • Committive consequence: If S is committed to p, then S is committed to q. • Permissive consequence: If S is committed and entitled to p, then S is (prima facie) entitled to q. " And those who introduce the notion of connexion say th...

The present study comprises physicochemical and phytochemical evaluation of arial parts of Eclipta alba in different extracts using ethanol, petroleum ether, benzene, chloroform and aqueous solvents by using standard methods. The physical evaluation was carried out for the determination physiochemical profile such as ash values and extractive values, whereas phytochemical evaluation was carried...

Introduction Conclusions References

Introduction: Development of new pulp capping agents has paved the way towards the preservation of pulp vitality, which is an important goal in restorative dentistry. This study sought to assess the calcium ion release, pH and setting of mineral trioxide aggregate (MTA) Angelus, an experimental formulation of nano-hybrid MTA containing nano-SiO2, nano-Al2O3 and nano-TiO2 and MTA Angelus plus na...

Plants have evolved many systems to prevent undesirable fertilization. Among these, incompatibility is a well-organized system in which pollen germination or pollen tube growth is inhibited in pistils. We previously found that a novel one-way pollen-stigma incompatibility response [unilateral incompatibility (UI)] occurred between two self-incompatible Brassica rapa plants, a Turkish line, and ...

A careful comparative analysis suggests a simple explanation for a category of exceptions to the general correlation between separate sexes in plants -- dioecy -- and self-incompatibility. In some genera, polyploidy causes failure of self-incompatibility, and dioecy may then evolve.