What became of Hystrix?

Hystrix Moench was a perennial genus of the Triticeae. Its members differed from those of other genera in the tribe in lacking glumes. The type species is H. patulaMoench, a North American taxon. When it became accepted that H. patula should be included in Elymus, Hystrix could not be used as a generic name. The problem became how to treat the other species that had been included in Hystrix. Hystrix patula, like many other species of Elymus, has the StH genomic composition but H. coreana (Honda) Ohwi, H. californica (Bol.) Kuntze, H. duthiei (Stapf) Bor ssp. duthiei, and H. duthiei ssp. longearistata have the NsXm genomic composition that is associated with Leymus. Using genomic in situ hybridization analysis, we showed that H. komarovii (Roshev.) Ohwi has an NsE^e genomic composition, a combination not known from any other species. Hystrix sibirica (Trautv.) Kuntze and H. duthiei ssp. japonica are included in Leymus on morphological grounds. The status of H. kunlunensis K. S. Hao is not clear. In this paper, we summarize our results and those of others concerning what is now known and the problems that remain concerning the species that used to be included in Hystrix.     

What is the function of centrioles?

The function of centrioles has been controversial and remains incompletely resolved. This is because centrioles, in and of themselves, do not directly perform any physiological activity. Instead, their role is only to act as a jig or breadboard onto which other functional structures can be built. Centrioles are primarily involved in forming two structures-centrosomes and cilia. Centrioles bias the position of spindle pole formation, but because spindle poles can self-organize, the function of the centriole in mitosis is not obligatory. Consequently, lack of centrioles does not generally prevent mitosis, although recent experiments suggest acentriolar spindles have reduced fidelity of chromosome segregation. In contrast, centrioles are absolutely required for the assembly of cilia, including primary cilia that act as cellular antennae. Consistent with this requirement, it is now becoming clear that many ciliary diseases, including nephronophthisis, Bardet-Biedl syndrome, Meckel Syndrome, and Oral-Facial-Digital syndrome, are caused by defects in centriole-associated proteins.     

What Is the Tree of Life?

A universal Tree of Life (TOL) has long been a goal of molecular phylogeneticists, but reticulation at the level of genes and possibly at the levels of cells and species renders any simple interpretation of such a TOL, especially as applied to prokaryotes, problematic.One of the several ways in which microbiology puts the neo-Darwinian synthesis in jeopardy is by the threatening to “uproot the Tree of Life (TOL)” [1]. Lateral gene transfer (LGT) is much more frequent than most biologists would have imagined up until about 20 years ago, so phylogenetic trees based on sequences of different prokaryotic genes are often different. How to tease out from such conflicting data something that might correspond to a single, universal Tree of Life becomes problematic. Moreover, since many important evolutionary transitions involve lineage fusions at one level or another, the aptness of a tree (a pattern of successive bifurcations) as a summary of life’s history is uncertain [2–4].     

Out of Africa? What do genes tell us?

Genetic diversity patterns in nuclear versus mitochondrial systems and in low versus high mutation rate systems do not support the hypothesis of a recent African origin for all of humanity following a split between Africans and non-Africans 100,000 years ago, nor do genetic distance data. Geographical analyses of nuclear and mitochondrial gene trees do not support the hypothesis of a recent global replacement of humans coming out of Africa, although a local replacement event in Europe is indicated by these analyses and recent studies on Neandertal DNA. The gene tree analyses instead indicate that genetic interchanges have ensured that all of humanity has evolved as a single evolutionary lineage with no major splits.     

What caused extinction of the Pleistocene megafauna of Sahul?

During the Pleistocene, Australia and New Guinea supported a rich assemblage of large vertebrates. Why these animals disappeared has been debated for more than a century and remains controversial. Previous synthetic reviews of this problem have typically focused heavily on particular types of evidence, such as the dating of extinction and human arrival, and have frequently ignored uncertainties and biases that can lead to misinterpretation of this evidence. Here, we review diverse evidence bearing on this issue and conclude that, although many knowledge gaps remain, multiple independent lines of evidence point to direct human impact as the most likely cause of extinction.     

What kind of lamp for the cultivation of algae?

A method for quantitative evaluation of light sources from the point of their suitability for algal cultivation is described. Two parameters are used for the evaluation:

What is the value of oncology medicines?

Coverage with evidence development (CED), rather than quality-adjusted-life-year (QALY) thresholds, offers the best way forward in balancing evidence-based policy for new oncology products with the needs of developers, payers, physicians and patients.     

What is the function of the claustrum?

The claustrum is a thin, irregular, sheet-like neuronal structure hidden beneath the inner surface of the neocortex in the general region of the insula. Its function is enigmatic. Its anatomy is quite remarkable in that it receives input from almost all regions of cortex and projects back to almost all regions of cortex. We here briefly summarize what is known about the claustrum, speculate on its possible relationship to the processes that give rise to integrated conscious percepts, propose mechanisms that enable information to travel widely within the claustrum and discuss experiments to address these questions.