Speciation dynamics in the SE Asian tropics: Putting a time perspective on the phylogeny and biogeography of Sundaland tree squirrels, Sundasciurus

Tropical rainforests are well known for their extraordinarily high levels of biodiversity. The origin of this species richness is still debated. For instance, the museum hypothesis states that over evolutionary time more and more species will accumulate with relatively few extinctions. In contrast, the Pleistocene diver- sification model argues that during the last 2 million years, climatic factors (glaciations) caused environ- mental changes that drove isolation and vicariant speciation events. In this study, we construct a molecular phylogeny of the Sundaland (Malay Peninsula, Sumata, Borneo, Palawan) and Greater Minda- nao (Mindanao, Samar, Leyte) tree squirrels (genus Sundasciurus). Our results show that most speciation events in this forest dependent taxon occurred before the Pleistocene and that even the timing of intra- specific splits among populations from different landmasses are relatively old. Additionally, we found unexpectedly high divergence within and between highland populations of S. tenuis on Sumatra and the Malay Peninsula, highlighting the importance of Pliocene events in both speciation and within species divergences in this regionPeer reviewe

The Texas Nature Tracker

A newsletter providing information about environmental monitoring, endangered species, and nature conservation within Texas

Diagonal conditions in ordered spaces

Abstract. For a space X and a regular uncountable cardinal κ ≤ |X| we say that then we say that X has a small diagonal, and if every regular uncountable κ ≤ |X| belongs to D(X) then we say that X has an H-diagonal. In this paper we investigate the interplay between D(X) and topological properties of X in the category of generalized ordered spaces. We obtain cardinal invariant theorems and metrization theorems for such spaces, proving, for example, that a Lindelöf linearly ordered space with a small diagonal is metrizable. We give examples showing that our results are the sharpest possible, e.g., that there is a first countable, perfect, paracompacť Cech-complete linearly ordered space with an H-diagonal that is not metrizable. Our example shows that a recent CH-result of Juhász and Szentmiklóssy on metrizability of compact Hausdorff spaces with small diagonals cannot be generalized beyond the class of locally compact spaces. We present examples showing the interplay of the above diagonal conditions with set theory in a natural extension of the Michael line construction

1968: Abilene Christian College Bible Lectures - Full Text

CROWNING FIFTY YEARS” Being the Fiftieth Annual ABILENE CHRISTIAN COLLEGE BIBLE LECTURES - 1968 J. D. THOMAS, LECTURESHIP DIRECTOR, EDITOR Published by ABILENE CHRISTIAN COLLEGE ACC Station, Abilene, Texas 7960

Selective Enrichment and Sequencing of Whole Mitochondrial Genomes in the Presence of Nuclear Encoded Mitochondrial Pseudogenes (Numts)

Numts are an integral component of many eukaryote genomes offering a snapshot of the evolutionary process that led from the incorporation of an α-proteobacterium into a larger eukaryotic cell some 1.8 billion years ago. Although numt sequence can be harnessed as molecular marker, these sequences often remain unidentified and are mistaken for genuine mtDNA leading to erroneous interpretation of mtDNA data sets. It is therefore indispensable that during the process of amplifying and sequencing mitochondrial genes, preventive measures are taken to ensure the exclusion of numts to guarantee the recovery of genuine mtDNA. This applies to mtDNA analyses in general but especially to studies where mtDNAs are sequenced de novo as the launch pad for subsequent mtDNA-based research. By using a combination of dilution series and nested rolling circle amplification (RCA), we present a novel strategy to selectively amplify mtDNA and exclude the amplification of numt sequence. We have successfully applied this strategy to de novo sequence the mtDNA of the Black Field Cricket Teleogryllus commodus, a species known to contain numts. Aligning our assembled sequence to the reference genome of Teleogryllus emma (GenBank EU557269.1) led to the identification of a numt sequence in the reference sequence. This unexpected result further highlights the need of a reliable and accessible strategy to eliminate this source of error