Six genic mutations restricting clones to mating type VII (O) were isolated in syngen 4, Paramecium aurelia. The only three extensively tested were neither allelic nor closely linked. A second type of mutation, allelic to one of the O restricted mutants, was also found. Clones homozygous for this mutant gene were selfers, producing both O and E (VIII) mating types, but only when they were proge...

Mammals and birds have evolved three primary, discrete, interrelated emotion-motivation systems in the brain for mating, reproduction, and parenting: lust, attraction, and male-female attachment. Each emotion-motivation system is associated with a specific constellation of neural correlates and a distinct behavioral repertoire. Lust evolved to initiate the mating process with any appropriate pa...

The reversal of conventional sex roles was enigmatic to Darwin, who suggested that it may evolve when sex ratios are female biased [1]. Here we present direct evidence confirming Darwin's hypothesis. We investigated mating system evolution in a sex-role-reversed beetle (Megabruchidius dorsalis) using experimental evolution under manipulated sex ratios and food regimes. In female-biased populati...

We used radiotelemetric data and behavioural observations to characterize seasonal (mating versus post-mating seasons) and sexual variation in movement patterns, as well as to examine some of the ecological factors contributing to the evolution of the mating system in a venomous predator from the Mojave Desert of North America, the speckled rattlesnake, Crotalus mitchellii. Mating occurs in spr...

Recent comparative genomics and mutational studies of the genes regulating mating and meiosis in fungi provide new insights into not only the variability of the key genes, but also the plasticity of the regulatory circuitry in the evolution of mating systems.

Sexual imprinting is a common mechanism of mate preference learning. It is thought to influence how traits evolve and in some cases to promote speciation. Recently there has been increasing interest in how sexual imprinting itself evolves. Theoretical work on polygynous mating systems predicts that females will evolve paternal imprinting, which means they learn to prefer phenotypes expressed by...

In this report, a rare case of pregnancy in a mouse without mating and during breastfeeding is presented. Out-bred NMRI mice were prepared for mating. Two female mice without superovulation were caged with one male. The next morning, vaginal plaque was not detected; therefore, females were kept in the cage with the same male for 4 more days. One of the females delivered 4 offspring: one female ...

Homobasidiomycetes include the majority of wood-decaying fungi. Two basic forms of wood decay are known in homobasidiomycetes: white rot, in which lignin and cellulose are degraded, and brown rot, in which lignin is not appreciably degraded. An apparent correlation has been noted between production of a brown rot, decay of conifer substrates, and possession of a bipolar mating system (which has...

Abstract Background Pair bonding with a reproductive partner is rare among mammals but an important feature of human social behavior. Decades research on monogamous prairie voles ( Microtus ochrogaster ), along comparative studies using the related non-bonding meadow vole M. pennsylvanicus have revealed many neural and molecular mechanisms necessary for pair-bond formation in that species. Howe...