Scientists at the Wellcome Sanger Institute are about to embark on a monumental task - sequencing the genomes of all life on Earth. This ambitious project has already made significant strides, but it's only just begun its latest phase with a focus on the microscopic tardigrade, recently crowned 'Invertebrate of the Year' after a public vote.
Led by postdoctoral researcher Witek Morek, an expert in tardigrades, the initial steps involve carefully collecting moss and lichen samples from the institute's campus. These are then brought back to the lab where the tiny creatures are extracted. Tardigrades, famed for their ability to survive extreme conditions, including scorching heat, freezing cold, and even space, are a fascinating subject for genomic study.
Professor Mark Blaxter, who heads the Tree of Life programme, says advances in sequencing technology have made this ambitious project feasible. In the early stages of his career, it took 25 years to sequence 18 genomes - now they can sequence 48 every week. To date, the initiative has successfully sequenced 2,600 genomes, ranging from whales to fungi, with a particular emphasis on species found across Britain and Ireland.
A genome acts as the complete set of instructions for building an organism, encoded in DNA. Genomics extends beyond individual genes to encompass all the DNA within an organism. Establishing these 'reference genomes' allows scientists to gain a deeper understanding of species' biology and evolutionary paths. This research also holds potential to uncover new medicines and compounds, offering significant benefits to human health and other sectors.
The sequencing process is meticulous: after isolating tardigrades from moss and lichen samples, Morek identifies individual specimens, noting their characteristics such as gut contents and egg shapes, crucial for species identification. Once identified, the tardigrades are carefully transferred to barcoded tubes and frozen at -71°C, awaiting DNA extraction and sequencing.
Four high-quality tardigrade genomes are already available in public databases, with Morek working on 14 more and around 50 species awaiting sequencing in the institute's freezers. This extensive project builds upon earlier milestones in genomics, including the sequencing of the first animal genome - a nematode worm - in 1998, followed by the initial human genome sequence five years later, completed fully in 2021.