By analyzing DNA from illegally trafficked elephant tusks, a group led by scientists from the University of Washington has developed a framework for identifying transnational criminal organizations involved in the ivory trade. Aiming to develop tools that can be used to help prosecute and convict poachers, the researchers genetically matched thousands of tusks from the same elephant or close relatives from 49 shipments out of Africa that were seized between 2002 and 2019. As reported in this week's Nature Human Behavior, they uncover a pattern wherein tusks from the same individual or close relatives are found in separate seizures that were contained in, and transited through, common African ports. Their findings also suggest that individual traffickers are exporting dozens of shipments, with considerable connectivity between traffickers operating in different ports. The work "provides a basis to strengthen investigations and prosecutions," the study's authors write. "It enables law enforcement to connect evidence from multiple independent investigations and supports indictments and prosecutions of transnational ivory traffickers for the totality of their crimes." The Scan has more on this, here.
A new method for efficiently processing low cell input samples for single-cell RNA sequencing experiments is reported in this week's Nature Methods. The development of scRNA-seq has transformed biomedical science, enabling the dissection of cellular heterogeneity by high-dimensional data, but the technology is currently tailored to large cell inputs. As a result, scRNA-seq approaches are inefficient and costly when processing small, individual tissue samples. To address this shortcoming, a team from the École Polytechnique Fédérale de Lausanne developed a deterministic, mRNA-capture bead and cell co-encapsulation dropleting system — dubbed DisCo — for low cell input scRNA-seq. The method relies on machine vision to actively detect cells and coordinate their capture in droplets, allowing for continuous operation and enabling free per-run scaling and serial processing of samples. Its developers demonstrate that the approach can efficiently process samples containing only a few hundred cells by using it to analyze 31 individual intestinal organoids at varying developmental stages, as well as individual mouse intestinal crypts. "We believe that the utility of the approach described here extends to research on all developing multicellular organisms and, coupled with lineage tracing, might offer an entirely new perspective on interindividual variation," the scientists write. "Finally, we expect this approach to be applicable to rare, small clinical samples to gain detailed insights into disease-related cellular heterogeneity and dynamics."