Species extinctions in the tropics are accelerating, outpacing documentation efforts. Meanwhile, DNA barcoding is flourishing in the Global North, backed by extensive infrastructure, allowing non-taxonomic experts to identify species from nonlethal, minimally invasive, and environmental samples. However, hyper-diverse regions like Peru make up only 0.52% (n = 93,246) of the Barcode of Life Database (BOLD). To address this, we established three decentralized laboratories with low-cost, portable nanopore sequencers. From 2018–2023, we generated 1,858 barcodes in situ using six genetic markers for 1,097 vertebrates and 76 plants from existing and new biobanks. We present the first genetic barcodes for 30 mammal and 196 bird species from Peruvian specimens, increasing the number of Peruvian mammal and bird species in BOLD by 110% and 36.5% respectively. We also report the first records of the marsupial Marmosops ocellatus and the bat Sturnira lilium for Peru. This dataset represents an effort to go from fresh or museum-preserved samples to barcodes entirely in situ, avoiding the export of samples outside the country, and facilitating local capacity in molecular biodiversity research.

Ancient environmental DNA is increasingly vital for reconstructing past ecosystems, particularly when paleontological and archaeological tissue remains are absent. Detecting ancient plant and animal DNA in environmental samples relies on using extensive eukaryotic reference genome databases for profiling metagenomics data. However, many eukaryotic genomes contain regions with high sequence similarity to microbial DNA, which can lead to the misclassification of bacterial and archaeal reads as eukaryotic. This issue is especially problematic in ancient eDNA datasets, where plant and animal DNA is typically present at very low abundance. In this study, we present a method for identifying bacterial- and archaeal-like sequences in eukaryotic genomes and apply it to nearly 3,000 reference genomes from NCBI RefSeq and GenBank (vertebrates, invertebrates, plants) as well as the 1,323 PhyloNorway plant genome assemblies from herbarium material from northern high-latitude regions. We find that microbial-like regions are widespread across eukaryotic genomes and provide a comprehensive resource of their genomic coordinates and taxonomic annotations. This resource enables the masking of microbial-like regions during profiling analyses, thereby improving the reliability of ancient environmental metagenomic datasets for downstream analyses.

Foldscopes are ultra-low-cost paper microscopes invented by Manu Prakash and Jim Cybulski at Stanford University. They are about as light as a pencil and waterproof, all whilst offering similar optic quality to traditional microscopes. Foldscopes do not require electricity or glass slides to be used, which increases the possibilities of their use in education and outreach activities with children or people with disabilities. In 2019, thanks to a material grant of 100 foldscopes from One World Science and additional purchased foldscopes, I designed and implemented a science workshop called Exploradores del Microcosmos, or Explorers of Microcosmos in English. The aim of the workshop was to help make microscopy more accessible, in particular at underfunded schools, and stimulate active learning about ecosystems and evolution in the participants. Within this article, I describe the workshop and relay my personal insights and reflections on its execution across multiple schools and groups in Mexico.