Morphological and genetic differentiation in the anguid lizard Pseudopus apodus supports the existence of an endemic subspecies in the Levant

The Levant represents one of the most important reptile diversity hotspots and centers of endemism in the Western Palearctic. The region harbored numerous taxa in glacial refugia during the Pleistocene climatic oscillations. Due to the hostile arid conditions in the warmer periods they were not always able to spread or come into contact with populations from more distant regions. One large and conspicuous member of the Levantine herpetofauna is the legless anguid lizard Pseudopus apodus. This species is distributed from the Balkans to Central Asia with a portion of its range running along the eastern Mediterranean coast. Mitochondrial and nuclear DNA sequences, microsatellite genotypes, and morphology show that populations in this region differ from the two named subspecies and presumably had a long independent evolutionary history during the Quaternary. Here we describe the Levantine population as a new subspecies and present biogeographic scenarios for its origin and diversification. The new subspecies is genetically highly diverse, and it forms a sister lineage to Pseudopus from the remaining parts of the range according to mtDNA. It is the largest-bodied of the three subspecies, but occupies the smallest range.

Meiotic drive is associated with sexual incompatibility in Neurospora

Meiotic drive is the phenomenon whereby selfish elements bias their transmission to progeny at ratios above 50:50, violating Mendel’s law of equal segregation. The model fungus Neurospora carries three different meiotic drivers, called Spore killers. Two of these, Sk-2 and Sk-3, are multilocus spore killers that constitute large haplotypes and are found in the species N. intermedia. Here we used molecular markers to determine that all N. intermedia isolates from New Zealand in fact belong to the sister species N. metzenbergii. Additionally, we use laboratory crosses to demonstrate that Sk-2 and Sk-3 are involved in sexual incompatibility between N. intermedia and N. metzenbergii.. Our experiments revealed that while crosses between these two species normally produced viable progeny at appreciable rates, when strains of N. intermedia carried Sk-2 or Sk-3 the proportion of viable progeny dropped substantially and in some crosses, no viable progeny were observed. Backcrossings supported that the incompatibility is tightly linked to the Sk haplotype. Finally, it appears that Sk-2 and Sk-3 have accumulated different incompatibility phenotypes when crossed with N. metzenbergii strains, consistent with their independent evolutionary history. This research illustrates how meiotic drive can contribute to reproductive isolation between populations, and thereby speciation.

Systematics of Berberis sect. Wallichianae (Berberidaceae) of Taiwan and Luzon with description of three new species, B. schaaliae, B. ravenii, and B. pengii

Berberis sect. Wallichianae are species of evergreen shrubs that in Taiwan are found in subalpine and montane-temperate areas and which have a notoriously controversial taxonomic history. Based on multivariate statistical analyses of morphometric data and an explicitly stated species criterion, the taxonomy of the group in Taiwan and its close relative in Luzon (B. barandana) is revised and their endemicity is evaluated by molecular data. In addition to the six species recognized in the Flora of Taiwan, 2nd ed. (i.e., B. aristatoserrulata, B. brevisepala, B. chingshuiensis, B. kawakamii, B. mingetsensis, and B. tarokoensis), B. hayatana (synonymized under B. mingetsensis) and B. nantoensis (synonymized under B. brevisepala) are reinstated, and three new species (B. pengii, B. ravenii, and B. schaaliae) are described and illustrated. Phylogenetic analyses using three chloroplast DNA sequence regions (rbcL, ycf6-psbM, and psbA-trnH) place all Taiwanese species and B. barandana in a strongly supported clade derived from within the continental Asian species of sect. Wallichianae, indicating their independent evolutionary history and supporting their endemic status.

WHEAT EVOLUTION

Many wild and cultivated wheat species are amphidiploid, i.e., they are polyploid species containing two or more distinct nuclear genomes, each with its own independent evolutionary history, but whose genetic behavior resembles that of diploids. Amphidiploidy has important evolutionary consequences in wheat. Since the beginning of this century different methods have been employed to identify the diploid donors of the coexisting genomes in the polyploids. To date, several of the genomic donors have been identified, and the search for the others has been narrowed down considerably. Molecular methodologies that are being increasingly used in studies aimed at reconstructing the evolutionary history of wheat species and their wild relatives have resolved many of the phylogenetic relationships among the various taxa.

Conceptual aspects of the quantification of the extent of biological diversity

This paper begins by asking to what extent numbers of species are an adequate measure of biological diversity, either locally or globally; both for evolutionary understanding and for practical applications, biodiversity may often be better quantified at lower or higher levels, from genes to ecosystems. The subsequent discussion, however, focuses on species, and discusses questions that arise in estimating how many species there have ever been, how many there currently are in various taxonomic groups, and how we may quantify the differing degrees of ‘independent evolutionary history’ or ‘taxonomic distinctiveness’ in different species or groups. I conclude with opinions about how the practical task of identifying and recording species diversity might be better managed.