The negative fitness consequences of close inbreeding are widely recognized, but predicting the long-term effects of inbreeding and genetic drift due to limited population size is not straightforward. As the frequency and homozygosity of recessive deleterious alleles increase, selection can remove (purge) them from a population, reducing the genetic load. At the same time, small population size...

Inbreeding depression is usually quantified by regressing individual phenotypic values on inbreeding coefficients, implicitly assuming there is no correlation between an individual's phenotype and the kinship coefficient to its mate. If such an association between parental phenotype and parental kinship exists, and if the trait of interest is heritable, estimates of inbreeding depression can be...

Inbreeding depression is a general phenomenon that is well documented in many plants and animals. Furthermore, it is generally considered to be the driving force behind mating-system evolution. Traditionally, the focus has been on the mean level of inbreeding depression in populations. However, more recently, the variation in inbreeding depression among individuals within populations has been s...

Quadratic partial regression coefficients were estimated for the inbreeding level on five performance traits (body weight, average egg weight, age at first egg, percentage of fertilized eggs, and hatchability of set eggs) of two strains of laying hens. Data on 5631 of H77 layers and 3563 of N88 layers from nine consecutive generations were analysed. Only dams were accounted for. Partial regress...

Inbreeding, which is common in plants, may increase the vulnerability of populations to natural enemies. Similarly, natural enemies may increase the expression of inbreeding depression in their hosts, resulting in altered selection on host mating-system evolution. To examine effects of inbreeding on tolerance to herbivory, we transplanted experimentally selfand cross-fertilized plants into four...

Purdue University Cooperative Extension Service West Lafayette, IN 47907 Author: David S. Buchanan, Oklahoma State University, Reviewers: Kreg Leymaster, USDA MARC, Clay Center NE; Ken Stalder, Univ. of Tennessee, Jackson, TN; William Luce, Oklahoma State Univ., Stillwater, OK Inbreeding is the mating of individuals that are related. In the strict sense, all members of a breed are related. As a...

A recent study on the Holstein/Friesian (HOL) breed has indicated that the rapid rise in percentage Holstein genes in the United Kingdom (UK) has been accompanied by an increasing rate of inbreeding (Kearney et al., 2004). They reported an average inbreeding rate of 0.17% per year since 1992. Some of the consequences of inbreeding, for instance, inbreeding depression, are expected to be more pr...

Inbreeding is essentially the mating of animals that are related. Within the pedigree of the mated sire and dam, one or more animals will be in common; resulting in progeny with a certain level of inbreeding. The level of inbreeding will depend on the relationship between the two mated animals, with the closer the relationship, the greater the level of inbreeding that will occur in the resultin...

effect of a given system of consanguineous mating on the degree of homoTrEgosity of resulting individuals is conveniently described by means of the coefficient of inbreeding (WRIGHT 1921 ) . The coefficient of inbreeding, F, of an individual may be defined to be the probability that the two genes possessed by that individual at a locus are identical by descent (MAL~COT 1948; KEMPTHORNE 1957). T...