Biosciences, College of Environmental and Life Sciences, The University of Exeter, Exeter, EX4 4QD, UK.
Published: February 2019
AI Article Synopsis
Article Abstract
Botryococcus braunii is a colonial microalga that appears early in the fossil record and is a sensitive proxy of environmental and hydroclimatic conditions. Palaeozoic Botryococcus fossils which contribute up to 90% of oil shales and approximately 1% of crude oil, co-localise with diagnostic geolipids from the degradation of source-signature hydrocarbons. However more recent Holocene sediments demonstrate no such association. Consequently, Botryococcus are identified in younger sediments by morphology alone, where potential misclassifications could lead to inaccurate paleoenvironmental reconstructions. Here we show that a combination of flow cytometry and ancient DNA (aDNA) sequencing can unambiguously identify Botryococcus microfossils in Holocene sediments with hitherto unparalleled accuracy and rapidity. The application of aDNA sequencing to microfossils offers a far-reaching opportunity for understanding environmental change in the recent geological record. When allied with other high-resolution palaeoenvironmental information such as aDNA sequencing of humans and megafauna, aDNA from microfossils may allow a deeper and more precise understanding of past environments, ecologies and migrations.
Environmental Microbiology Laboratory, Department of Agricultural Biological Chemistry, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, South Korea.
The is a group of ancient fungi with global distribution. In the current study we accessed mucoralean fungi isolated from two countries on opposite sides of the Earth and in different hemispheres: South Korea and Brazil. isolates were obtained from freshwater, soil, invertebrates, and fruit seeds and identified using phenotypic techniques combined with the DNA sequence data.
The Japanese Archipelago consists of a series of isolated yet interconnected islands off the Eurasian continent. The linear topography of the archipelago presents a unique biogeographic context for the dispersal of organisms from the continent. In this study, mitochondrial DNA (mtDNA) and single-nucleotide polymorphism (SNP) variation were employed to elucidate the dispersal history of the Japanese clouded butterfly (Parnassius glacialis) across the Japanese Archipelago, including the northern island (Hokkaido), the main island (Honshu), and Shikoku Island.
Animal genomes are packaged into chromatin, a highly dynamic macromolecular structure of DNA and histone proteins organised into nucleosomes. This accommodates packaging of lengthy genomic sequences within the physical confines of the nucleus while also enabling precise regulation of access to genetic information. However, histones existed before chromatin and have lesser-known functions beyond genome regulation.
Group II introns are ancient self-splicing ribozymes and retrotransposons. Though long speculated to have originated before translation, their dependence on intron-encoded proteins for splicing and mobility has cast doubt on this hypothesis. While some group II introns are known to retain part of their catalytic repertoire in the absence of protein cofactors, protein-free complete reverse splicing of a group II intron into a DNA target has never been demonstrated.
During the Early Medieval period, the Carpathian Basin witnessed substantial demographic shifts, notably under the Avar dominance for ~250 years, followed by the settlement of early Hungarians in the region during the late 9th century CE. This study presents the genetic analysis of 296 ancient samples, including 103 shotgun-sequenced genomes, from present-day Western Hungary. By using identity-by-descent segment sharing networks, this research offers detailed insights into the population structure and dynamics of the region from the 5th to 11th centuries CE, with specific focus on certain microregions.
