Individuals are generally predicted to avoid inbreeding because of detrimental fitness effects. However, several recent studies have shown that limited inbreeding is tolerated by some vertebrate species. Here, we examine the costs and benefits of inbreeding in a largely polygynous rodent, the yellow-bellied marmot (Marmota flaviventris). We use a pedigree constructed from 8 years of genetic dat...

OBJECTIVE Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension in adulthood. In an attempt to define the mechanisms whereby blood pressure may be raised, we have hypothesized that arteries from offspring of nutritionally restricted dams exhibit abnormalities in the endothelial function and in nitric oxide synthesis....

CONTEXT Few systematic data exist on survival and reproduction among males with birth defects and their contribution to occurrence of birth defects in the next generation. OBJECTIVE To estimate survival of males with registered birth defects, their subsequent reproduction rates, and their risk of transmitting birth defects to their offspring. DESIGN AND SETTING Population-based cohort study...

Sex allocation is the apportioning of parental resources to male versus female offspring in a sexually reproducing species. Sex allocation theory assumes that natural selection favours parents that modify their investment into male and female offspring in such a way that it maximizes the parent’s fitness (Fisher 1930; Charnov 1982). Fisher’s equal allocation theory (1930) states that selection ...

Sexual selection is among the most powerful of all evolutionary forces. It occurs when individuals within one sex secure mates and produce offspring at the expense of other individuals within the same sex. Darwin was first to recognize the power of sexual selection to change male and female phenotypes, and, in noting that sexual selection is nonubiquitous, Darwin was also first to recognize the...

Aggressive behavior in females is thought to be costly due to a trade-off between aggression and parental care. In biparental systems, resolution of this trade-off may depend on the extent to which males mitigate the cost of female aggression. Using a population of tree swallows (Tachycineta bicolor) in which intrasexual aggression has been shown to be beneficial to females in acquiring a nesti...

Emerging evidence has demonstrated that paternal alcohol use can modify the behavior of offspring, particularly male offspring. However, preclinical studies to date have not used voluntary self-administration of alcohol to examine alcohol-related behaviors in offspring. Here, we tested the hypothesis that paternal alcohol self-administration followed by punishment-imposed abstinence alters alco...

The male reproductive system consists of the hypothalamus, the anterior pituitary gland, and the testes. Alcohol can interfere with the function of each of these components, thereby causing impotence, infertility, and reduced male secondary sexual characteristics. In the testes, alcohol can adversely affect the Leydig cells, which produce and secrete the hormone testosterone. Studies found that...

Besides somatic cells, aromatase gene expression and its transduction in an active protein in germ cells provides evidence of an additional site for estrogen production within testes of some mammals. Together with the widespread distribution of estrogen receptors in testicular cells, these data illuminate the hormonal regulation of male reproductive function

Assisted reproduction is used to resolve infertility problems in human and in breeding programs to generate livestock. Except for gestation length and birth weight, perinatal outcome of children conceived by In Vitro Fertilization is similar to that of spontaneously conceived children. However, large offspring syndrome observed after In Vitro Production in livestock is quite alarming. The disti...