191 Safeguarding Habitats and Wildlife “Using our genomic approach, one can remove a single scale from a confiscated shipment in Hong Kong and determine that it came from an animal near Bata, Equatorial Guinea.” — Thomas Smith, professor of ecology and evolutionary biology, University of California, Los Angeles Pangolins are also migrating, just not on their own. Previous genetic research on pangolin scales looked at mitochondrial DNA. Plot that on a map, she says, “and you can get, ‘Oh, they’re in West Africa’—so anywhere from Senegal to Ivory Coast maybe.” Instead, Tinsman and her colleagues (including more than 20 African scientists who are authors on the Science paper) analyzed the animal’s whole genome and built the first rangewide set of genome sequences for pangolins. Shifting from genetics to genomics, “you can just get so much more data, so much finer resolution,” within 70 kilometers of error, says Tinsman. With that level of error, and enough samples, “you can get a really good sense of where pangolins are being poached and where they’re coming from.” To connect confiscated scales to their origins on the map, the team would need to gather samples of white-bellied pangolins from near their habitats, before they embarked on trafficking routes. Some pangolin parts would come from tissue specimens from natural history collections, but the easiest way was to go to local bushmeat markets, where hunted pangolins were brought for sale. Scientists in Nigeria, Gabon, and Cameroon—armed with GPS receivers to geotag their samples—would go to local markets, and, to avoid paying and supporting the poaching economy, would ask sellers for a donation. “Normally, they don’t care if you ask for the tongue,” says Tinsman. “They want to eat the meat and then sell the scales.” The team ultimately procured a total of 551 samples of blood, muscle, and scales from across the pangolins’ habitat, from Senegal and West Africa down to Zambia and Central East Africa. (Some of the samples had been gathered during a years-long disease surveillance project that ended years before the pandemic.) From these, they managed to extract 111 high-quality genome sequences, and by analyzing 96 individual changes to the genome, they identified five distinct population groups that were strongly associated with distinct geographic areas, from Sierra Leone to the Democratic Republic of Congo. Next, Tinsman and her colleagues began developing a process to quickly and cheaply sequence a pile of hundreds of scales confiscated at ports and markets and donated by the Hong Kong government. Ultimately the researchers analyzed 643 samples of scales, each tagged with a date between 2012 and 2018, when pangolin trafficking reached a new peak. Previously, the official seizures database had simply indicated Nigerian origins for pangolins that transited through Nigeria: 95 percent of seized animals have no recorded source other than Nigeria. That includes a seizure in 2018, when seven tons of scales were found in a cargo container in Hong Kong. The DNA painted a far more detailed—even opposite— picture. When traced to their true source, only 4.2 percent of pangolins that were shipped from Nigeria during that time originated there. Nigeria is a key hub, but most confiscated scales came from two major hot spots: along Cameroon’s southern border with Equatorial Guinea and Gabon, and from western Cameroon, near the border with Nigeria. When mapped over time, the scales reveal a decade-long shift. In 2012 and 2013, most shipments were dominated by pangolins from West Africa, but over time, the researchers
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