Biology subjects

Star, B.

Publications and source records attributed to Star, B..

3 recordsLinked to original sources

bioRxiv2018

Ancient DNA reveals the chronology of walrus ivory trade from Norse Greenland

The search for walruses as a source of ivory -a popular material for making luxury art objects in medieval Europe- played a key role in the historic Scandinavian expansion throughout the Arctic region. Most notably, the colonization, peak and collapse of the medieval Norse colony of Greenland have all been attributed to the proto-globalization of ivory trade. Nevertheless, no studies have directly traced European ivory back to distinct populations of walrus in the Arctic. This limits our understanding of how ivory trade impacted the sustainability of northern societies and the ecology of the species they relied on. Here, we compare the mitogenomes of 27 archaeological walrus specimens from Europe and Greenland (most dated between 900 and 1400 CE) and 10 specimens from Svalbard (dated to the 18th and 19th centuries CE) to partial mitochondrial (MT) data of over 300 modern walruses. We discover two monophyletic mitochondrial clades, one of which is exclusively found in walrus populations of western Greenland and the Canadian Arctic. Investigating the chronology of these clades in our European archaeological remains, we identify a significant shift in resource use from predominantly eastern sources towards a near exclusive representation of walruses from western Greenland. These results provide empirical evidence for the economic importance of walrus for the Norse Greenland settlements and the integration of this remote, western Arctic resource into a medieval pan-European trade network.

genomics↗

bioRxiv2018

A stainless-steel mortar, pestle and sleeve design for the efficient fragmentation of ancient bone

Ancient DNA (aDNA) bone extraction protocols routinely require the fragmentation of larger bone pieces into smaller pieces or powder prior to DNA extraction. To achieve this goal, different types of equipment such as oscillating ball mills, freezer mills, mortar and pestle, or drills can be used. Although all these approaches are suitable, practical drawbacks are associated with each method. Here, we present the design for a stainless-steel mortar and pestle, with a removable sleeve to contain bone material. The tool readily comes apart for ease of cleaning and its simplicity allows university workshops equipped with a lathe, boring tools and milling machine to make these components at local expense. We find that this design allows for the controlled fragmentation of ancient bone and that it significantly improves our sample throughput. We recommend this design as a useful, economical addition to existing laboratory equipment for the efficient handling of ancient bone.

genomics↗

bioRxiv2017

A single Vibrionales 16S rRNA oligotype dominates the intestinal microbiome in two geographically separated Atlantic cod populations

BackgroundHost-microbe interactions are particularly intriguing in Atlantic cod (Gadus morhua), as it lacks the MHC II complex involved in presentation of extracellular pathogens. Nonetheless, little is known about the diversity of its microbiome in natural populations. Here, we use 16S rRNA high-throughput sequencing to investigate the microbial community composition in gut content and mucosa of 22 adult individuals from two coastal populations in Norway, located 470 km apart.\n\nResultsWe identify a core microbiome of 23 OTUs (97% sequence similarity) in all individuals that comprises 93% of the total number of reads. The most abundant orders are classified as Vibrionales, Fusobacteriales, Clostridiales and Bacteroidales. While mucosal samples show significantly lower diversity than gut content samples, no differences in OTU community composition are observed between the two populations. The differential abundance of oligotypes within two common OTUs does reveal limited spatial segregation. Remarkably, the most abundant OTU consists of a single oligotype (order Vibrionales, genus Photobacterium) that represents nearly 50% of the reads in both locations.\n\nConclusionsOur results show that the intestinal bacterial community of two geographically separated coastal populations of Atlantic cod is dominated by a limited number of highly abundant 16S rRNA oligotypes shared by all specimens examined. The ubiquity of these oligotypes suggests that the northern coastal Atlantic cod gut microbiome is colonized by a limited number of species with excellent dispersal capabilities that are well suited to thrive in their host environment.

microbiology↗