Several hypotheses aim to explain the evolution of helping behavior, but conclusive experimental support for evaluating the relative importance of individual hypotheses is still larking We report on two field experiments* conducted to test the "territory inheritance" and "pay-to-stay" hypotheses in the cooperatively breeding cichlid fish Neolamprologus pulcher. The territory inheritance hypothe...

A genetic stock certiÞcation assay was developed to distinguish Russian honey bees from other European (Apis mellifera L.) stocks that are commercially produced in the United States. In total, 11 microsatellite and Þve single-nucleotide polymorphism loci were used. Loci were selected for relatively high levels of homogeneity within each group and for differences in allele frequencies between gr...

For many years, genetic improvement in swine herds was traditionally made by small breeders. Beginning in the last half of the 20 century, following the lead of corn hybrid companies, breeding companies and larger seedstock breeders moved to improve swine by employing stringent selection methods, developing specialized sire and dam lines and then synthetic lines to be sold to customers as comme...

The regional dynamics of pond-breeding amphibians are often discussed in the context of metapopulations, under the assumption that individual ponds support distinct subpopulations. We used a combination of indirect and direct methods to assess the spatial population structure of California tiger salamanders (Ambystoma californiense) relative to two basic requirements of metapopulation models: (...

Breeding programs produce large datasets that require efficient management systems to keep track of performance, pedigree, geographical and image-based data. With the development of DNA-based screening technologies, more breeding programs perform genotyping in addition to phenotyping for performance evaluation. The integration of breeding data with other genomic and genetic data is instrumental...

1. Understanding the effects of individual and population factors on variation in breeding dispersal (the movement of individuals between successive breeding sites) is key to identifying the strategies behind breeders' movements. Dispersal is often influenced by multiple factors and these can be confounded with each other. We used 13 years of data on the locations, mates, breeding success and a...

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At 45 wk of age, 99 roosters housed in individual cages were tested for avian leukosis-J strain virus (ALV-J); 32 tested positive and 67 tested negative. These roosters were fed a restricted diet to maintain weight to primary breeder specifications. Individual semen and ceca samples were analyzed for presence and level of Campylobacter. Population levels of Campylobacter in semen and ceca of AL...

The program "Nb_HetEx" estimates the effective number of breeders (N(b)) that produced the sampled progeny based on genotype counts contained in that sample. When the number of breeders is very small, there is an excess of heterozygotes in their progeny: the smaller the number of breeders, the larger the heterozygote excess. The Nb_HetEx program also estimates N(e) through the temporal method.