In the aquatic realm, asexual reproduction is rare in most phyla. However, it is common among protozoa, coelenterata (e.g. Hydroid polyps budding medusae), cladocera (e.g. parthenogenesis of Daphnia sp.), and among tunicates (thaliacea). Salps alternate between sexual and asexual reproduction (metagenesis), and doliolids have two asexual and one sexual stage in their lifecycle (Paffenhöfer and ...

Apomixis is a natural form of asexual reproduction through seeds that leads to viable offspring genetically identical to the mother plant. New evidence from sexual model species indicates that the regulation of female gametogenesis and seed formation is also directed by epigenetic mechanisms that are crucial to control events that distinguish sexuality from apomixis, with important implications...

As the pioneering research cited in the previous chapter demonstrates, the kinds and concentrations of nutrients affect the development of the asexual apparatus of watermolds. The beginning efforts to study the relationship between nutrition and morphogenesis, not only of the sporangia but of the sexual apparatus as well, were severely hampered by lack of attention to precise chemical definitio...

It is necessary to understand how environmental changes affect plant fitness to predict survival of a species, but this knowledge is scarce for lichens and complicated by their formation of sexual and asexual reproductive structures. Are the presence and number of reproductive structures in Lobaria pulmonaria, a threatened lichen, dependent on thallus size, and is their formation sequential? Do...

Theory suggests that occasional or conditional sex involving facultative switching between sexual and asexual reproduction is the optimal reproductive strategy. Therefore, the true 'paradox of sex' is the prevalence of obligate sex. This points to the existence of powerful, general impediments to the invasion of obligately sexual populations by facultative mutants, and recent studies raise the ...

Populations of Allium vineale commonly include individuals with very different allocation patterns to three modes of reproduction: sexual flowers, aerially produced asexual bulbils, and belowground asexual offsets. If selection is currently acting to maintain these different allocation patterns there must be a genetic basis for variation in allocation to these three reproductive modes. In addit...

Microarray analysis was used to identify transcriptional changes in early vegetative growth of the filamentous fungus Aspergillus nidulans. The results suggest that the previously identified conidiation genes dewA, fluG, and stuA may function in isotropic expansion during early vegetative growth and asexual reproduction.

Complex changes to UV radiation at the Earth's surface are occurring concurrently with ocean warming. Despite few empirical tests, jellyfish are hypothesised to be increasing in some parts of the world because they are robust to environmental stressors. Here we examine the effects of UV-B and ocean warming projections on zooxanthellate jellyfish polyps. We exposed Cassiopea sp. polyps to three ...

Background: Kalanchoe daigremontiana is an attractive model system for the study of the molecular mechanisms of somatic embryogenesis and organogenesis competence due to its formation of plantlets with adventitious roots on the leaf margins that are derived from somatic embryos. The suppression subtractive hybridization technique was used to investigate gene expression during asexual reproducti...

The booklouse, Liposcelis bostrychophila, is a worldwide pest of stored products. For decades, only thelytokous parthenogenetic reproduction was documented in L. bostrychophila. Male L. bostrychophila were first found in Hawaii in 2002. In 2009, a sexual strain was found in Arizona. We examined the morphology of both males and females of the Arizona strain and compared the Arizona sexual strain...