Biology subjects

Bogan, A.

Publications and source records attributed to Bogan, A..

2 recordsLinked to original sources

bioRxiv2020

The Pleistocene-Holocene aquatic molluscs as indicators of the past ecosystem changes in Transbaikalia (Eastern Siberia, Russia)

Data on historical change of the Transbaikalian malacofauna in the Neopleistocene and Holocene is presented. Fossil shells from archeological excavations of the ancient settlements dating from the Neolithic period to Medieval and also from a drill hole of the Neopleistocene alluvial deposits were collected. In total nine species of bivalve molluscs from the families Margaritiferidae, Unionidae, Limnocardiidae, Glycymerididae, including one marine species, and two gastropod species from families Viviparidae and Planorbidae were identified. The time of the existence of each fossil species was determined by radiocarbon dating. It was found that the species ranged in age from more 50,000 and 2,080-1,210 years ago. Five species inhabited the Transbaikal region and are locally extirpated in the present. Their disjunctive ranges in the past included southern Europe and Western and Eastern Siberia to Transbaikalia and in the east to Far East and Primorye of Russia. The time of existence and extirpation of the thermophilic species of genera Adacna, Planorbis, Lanceolaria and Amuropaludina corresponds to cycles of the warming and cooling in Pleistocene and Holocene according to regional climate chronological scales. It was possible to separate these species as indicators of paleoclimate. Change of the species composition of the malacofauna of region connected with natural cycles of climatochrons in the Pleistocene and Holocene is the appearance of the climatogenic succession. In the course of this succession the disappearance of the stenothermal species occurred on a regional level and decreasing their global ranges.

zoology↗

bioRxiv2018

Hybrid de novo assembly of the draft genome of the freshwater mussel Venustaconcha ellipsiformis (Bivalvia: Unionida).

Freshwater mussels (Bivalvia: Unionida) serve an important role as aquatic ecosystem engineers but are one of the most critically imperilled groups of animals. Here, we used a combination of sequencing strategies to assemble and annotate a draft genome of Venustaconcha ellipsiformis, which will serve as a valuable genomic resource given the ecological value and unique \"doubly uniparental inheritance\" mode of mitochondrial DNA transmission of freshwater mussels. The genome described here was obtained by combining high coverage short reads (65X genome coverage of Illumina paired-end and 11X genome coverage of mate-pairs sequences) with low coverage Pacific Biosciences long reads (0.3X genome coverage). Briefly, the final scaffold assembly accounted for a total size of 1.54Gb (366,926 scaffolds, N50 = 6.5Kb, with 2.3% of \"N\" nucleotides), representing 86% of the predicted genome size of 1.80Gb, while over one third of the genome (37.5%) consisted of repeated elements and more than 85% of the core eukaryotic genes were recovered. Given the repeated genetic bottlenecks of V. ellipsiformis populations as a result of glaciations events, heterozygosity was also found to be remarkably low (0.6%), in contrast to most other sequenced bivalve species. Finally, we reassembled the full mitochondrial genome and found six polymorphic sites with respect to the previously published reference. This resource opens the way to comparative genomics studies to identify genes related to the unique adaptations of freshwater mussels and their distinctive mitochondrial inheritance mechanism.

genomics↗