Understanding drivers of genetic diversity at the major histocompatibility complex (MHC) is vitally important for predicting how vertebrate immune defence might respond to future selection pressures and for preserving immunogenetic diversity in declining populations. Parasite-mediated selection is believed to be the major selective force generating MHC polymorphism, and while MHC-based mating p...

The maintenance of sex is an unresolved paradox in evolutionary biology, given the inherent twofold fitness advantage for asexuals. Parasitic helminths offer a unique opportunity to address this enigma. Parasites that can create novel antigenic strains are able to escape pre-existing host immunity. Viruses produce diversity through mutation with rapid clonal proliferation. The long generation t...

The masking of deleterious mutations by complementation and the reassortment of virus segments (virus sex) are expected to increase population genetic diversity among coinfecting viruses. Conversely, clonally reproducing or noncoinfecting virus populations may experience clonal interference where viral clones compete with one another, preventing selective sweeps. This dynamic reduces the effici...

Organisms with sexual and asexual reproductive systems benefit from both types of reproduction. Sexual recombination generates new combinations of alleles, whereas clonality favours the spread of the fittest genotype through the entire population. Therefore, the rate of sexual vs. clonal reproduction has a major influence on the demography and genetic structure of natural populations. We addres...

1 Studies focused on speciation have tried to explain the emergence of new species 2 but stopped short of studying what it means for the biodiversity patterns such as 3 abundance or diversity. Community ecologist, on the other hand, have studied how 4 such patterns are maintained, but they did not study the processes that formed the 5 basic components of these patterns. We here take advantage o...

PURPOSE The purpose of this study was to assess the cultural environment in the School of Dental Hygiene at the University of Texas Dental Branch (UTDB) at Houston. METHODS A 36-item questionnaire was developed and administered to first- (DH1; n=34) and second-year (DH2, n=33) dental hygiene students. Questions explored satisfaction with diversity and interactions with faculty, staff, patient...

In this paper, we argue that the metaphor form of a comparison (i.e., a topic-vehicle pair) is preferred over, and more comprehensible than, the simile form when the interpretive diversity for that comparison is high. Interpretive diversity refers to the richness of the figurative meaning of a comparison; it is high to the extent that more features or properties are related to the figurative me...

Postcopulatory sexual selection affects the evolution of numerous features ranging from mating behavior to seminal fluid toxicity to the size of gametes. In an earlier study of the effect of sperm competition risk on sperm size evolution, experimental populations of the nematode Caenorhabditis elegans were maintained either by outcrossing (sperm competition present) or by selfing (no sperm comp...