The aims of this study were to investigate the genetic background of foot-pad dermatitis (FPD) in 4 different broiler lines reared in 2 contrasting environments (pedigree or sib-test) and to evaluate the performance of simultaneous genetic selection for improved FPD and BW. Data were available for 4 generations from 4 broiler lines, bred with varying intensities of selection for growth. The ave...

Adaptive radiations have long served as living libraries to study the build-up of species richness; however, they do not provide good models for radiations that exhibit negligible adaptive disparity. Here, we review work on damselflies to argue that nonadaptive mechanisms were predominant in the radiation of this group and have driven species divergence through sexual selection arising from mal...

Selection coefficients and segregation parameters have been estimated in 18 randomly chosen lines carrying wild X chromosomes on the cn bw genetic background. Each line was studied in replicated crosses of four types, with approximately 100 replications per line per cross. Crosses in which male X chromosomes differed exhibited significant sex ratio heterogeneity. Maximum likelihood estimation o...

Current theory proposes that sex can increase genetic variation and produce high fitness genotypes if genetic associations between alleles at different loci are non-random. In case beneficial and deleterious alleles at different loci are in linkage disequilibrium, sex may i) recombine beneficial alleles of different loci, ii) liberate beneficial alleles from genetic backgrounds of low fitness, ...