Article history: Received 30 January 2008 Received in revised form 9 June 2008 Accepted 7 August 2008 Our aim was to ascertain inbreeding depression in the Spanish Purebred horses for eight body measurements. A total of 16,472 individuals were measured for height at withers, height at chest, leg length, body length, width of chest, heart girth circumference, knee perimeter and cannon bone circu...

Stressful environments are often said to increase the expression of inbreeding depression. Alternatively, Crow's "opportunity for selection" (the squared phenotypic coefficient of variation) sets a limit to how much selection can occur, constraining the magnitude of inbreeding depression. To test these hypotheses, we planted self- and cross-fertilized seeds of Brassica rapa into a factorial exp...

A thorough knowledge of relationships between host genotype and immunity to parasitic infection is required to understand parasite-mediated mechanisms of genetic and population change. It has been suggested that immunity may decline with inbreeding. However, the relationship between inbreeding level and a host's response to a novel immune challenge has not been investigated in a natural populat...

Owing to the remarkable progress of molecular techniques, heterozygosity-fitness correlations (HFCs) have become a popular tool to study the impact of inbreeding in natural populations. However, their underlying mechanisms are often hotly debated. Here we argue that these "debates" rely on verbal arguments with no basis in existing theory and inappropriate statistical testing, and that it is ti...

Evidence of inbreeding depression is commonly detected from the fitness traits of animals, yet its effects on population growth rates of endangered species are rarely assessed. We examined whether inbreeding depression was affecting Sierra Nevada bighorn sheep (Ovis canadensis sierrae), a subspecies listed as endangered under the U.S. Endangered Species Act. Our objectives were to characterize ...

The nonlinear effects of inbreeding were studied by comparing linear and curvilinear regression models of phenotypic performances on inbreeding coefficients for production traits (milk, fat, and protein yields) of Holstein cows in their first lactation. Three different regression models (linear, quadratic, and cubic) were introduced separately into a single-trait, single-lactation, random regre...

The relevance of inbreeding depression to the persistence of plant populations can depend upon whether stress magnifies inbreeding depression for fitness-related traits. To examine whether drought stress exacerbates inbreeding depression in gas exchange traits and biomass, we grew selfed and outcrossed progeny of inbred lines from two populations of Impatiens capensis in a greenhouse experiment...

In terms of sexual intercourse, the very last people we think about are our kin. Imagining inbreeding intercourse, whether it involves our closest kin or not, induces aversion in most people who invoke inbreeding depression problems or cultural considerations. Research has focused on the disgust felt when facing inbreeding intercourse between close kin but little is known about other responses....

We examine the inbreeding load for adult life span and mortality rates of two seed beetle species, Callosobruchus maculatus and Stator limbatus. Inbreeding load differs substantially between males and females in both study populations of C. maculatus--life span of inbred females was 9-13% shorter than the life span of outbred females, whereas the life span of inbred males did not differ from th...

We studied three closely related species of endangered gazelles (Gazella dorcas, Gazella dama and Gazella cuvieri) with different levels of inbreeding in order to determine at which intensities inbreeding influences ejaculate traits. We also examined whether fluctuating asymmetry (FA) is a reliable indicator of genetic as well as reproductive stress. Our results show that, within each populatio...