The prevalence of sexual conflict in nature, as well as the supposedly arbitrary direction of the resulting coevolutionary trajectories, suggests that it may be an important driver of phenotypic divergence even in a constant environment. However, natural selection has long been central to the operation of sexual conflict within populations and may therefore constrain or otherwise direct diverge...

A paternal-age effect and the exclusive paternal origin of mutations have been reported in Apert syndrome (AS). As the incidence of sporadic AS births increases exponentially with paternal age, we hypothesized that the frequency of AS mutations in sperm would also increase. To determine the frequency of two common FGFR2 mutations in AS, we developed allele-specific peptide nucleic acid-PCR assa...

Male reproductive health has been under scrutiny recently. Many studies in the literature have concluded that semen quality is declining and that the incidence of testicular cancers is increasing. The reason for this change has been attributed to damage in sperm chromatin. During in vivo reproduction, the natural selection process ensures that only a spermatozoon with normal genomic material ca...

The aim of this study was to evaluate sperm quality following separation and selection using a silane-coated silica colloid method (PureSperm ® ) or Percoll ® . Frozen/thawed sperm from buffalo bulls (n=5) were assigned to two groups. The first group was separated using a Percoll ® discontinuous gradient (45 and 90%) and the second group by a single layer of PureSperm ® . Sperm motility, concen...

Selection to avoid inbreeding is predicted to vary across species due to differences in population structure and reproductive biology. Over the past decade, there have been numerous investigations of postcopulatory inbreeding avoidance, a phenomenon that first requires discrimination of mate (or sperm) relatedness and then requires mechanisms of male ejaculate tailoring and/or cryptic female ch...

A selection for sperm quality was carried out in the White Plymouth Rock population of the Spelderholt institute. The percentage of morphologically abnormal spermatozoa was used as the most important selection criterion. The population was selected in two directions, viz. a line with a low incidence (Ll-line) of abnormal spermatozoa and a line with a high incidence (Hl-line). Cocks were examine...

The past two decades have seen extensive growth of sexual selection research. Theoretical and empirical work has clarified many components of pre- and postcopulatory sexual selection, such as aggressive competition, mate choice, sperm utilization and sexual conflict. Genetic mechanisms of mate choice evolution have been less amenable to empirical testing, but molecular genetic analyses can now ...

Sperm competition is a pervasive selective force in evolution, shaping reproductive anatomy, physiology and behaviour. Here, we present comparative evidence that varying sperm competition levels account for variation in the male reproductive anatomy of rodents, the largest and most diverse mammalian order. We focus on the sperm-producing testes and the accessory reproductive glands, which produ...