Researchers take a deep dive into the genetic origins of mustelid physiological and behavioral range

Within the order Carnivora, Mustelids are the most ecologically and taxonomically varied family. They inhabit a range of natural niches, from the tayra in the tropics to the wolverine in the subarctic, and have developed species-specific features relating to their feeding, reproductive strategy, and shape.

An international research team led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) compared the complete genomes of different mustelids to learn more about the molecular mechanisms of these adaptations.

Multiple causes of genomic variation, such as those that modify the number, position, direction, or size of genes in a species’ genome, were discovered to belong to candidate genes. The researchers note that this has to change because the later forms of genetic diversity are commonly overlooked in genome studies of wildlife species. The findings were published in the journal “Molecular Ecology.”

The Mustelidae, which comprises badgers, ferrets, weasels, and otters, is the most ecologically and taxonomically varied family within the animal order Carnivora. Even strongly linked mustelids are found in a variety of environments, each with its own set of problems. As a result, they developed a wide range of nutrition and reproduction-related behavioral, morphological, and physiological adaptations.

Mustelids offer wildlife geneticists the chance to unravel the origins of this diversity by identifying regions in the genome connected with ecologically relevant traits, thanks to recent advances in sequencing technologies and analytical solutions that allow the construction of draught genomes for many wild species.

We focused on the subfamily Guloninae, within which several species occupy a variety of ecological niches, ranging from the omnivorous tayra (Eira barbara) in the neotropics to the carnivorous wolverine (Gulo gulo) in the resource-scarce subarctic.”

Lorena Derežanin, Study First Author and PhD student, Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research

“This is the first study comparing the genomes of ecologically disparate species within this diverse subfamily and sheds light on how these species evolved,” added Klaus-Peter Koepfli, a Senior Research Scientist at George Mason University in the US and a co-author of the research.

The researchers created the first reference genome for the tayra and contrasted it to genomes for the wolverine and the sable (Martes zibellina), two additional Guloninae species with ecologically distinct ecological niches.

They discovered that structural variations, which influence parts of specific genes or multiple genes, are as crucial as “single nucleotide variants,” which are essentially single “letter” changes in the genetic code, in contributing to species differences in genes involved with ecologically relevant traits.

Our results are important, as they demonstrate that many types of processes responsible for genomic variation need to be considered, including those that can rapidly change the number and function of genes in a genome.”

 Lorena Derežanin, Study First Author and PhD student, Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research

“If we use the metaphor of a book to represent the DNA sequences in a genome, then the kind of changes we are talking about is akin to deleting, moving, or duplicating large chunks of text, on a scale of paragraphs, pages, or even whole chapters,” added Daniel Förster, a scientist at the Leibniz-IZW and the study senior author.

The researchers discovered changes in numerous genes that could be linked to the diverse ecologies of the species. They discovered several changes in pregnancy-related genes in the genome of the tayra, the only Guloninae species that breed all year. Many changed genes were linked to diet and body state in the wolverine, a circumpolar carnivore that must deal with seasonal food shortages.

In a sense, starving for longer periods is part of the wolverine lifestyle, and we identified candidate genes that allow them to cope with this. Generating further genomes for species from this diverse mammalian family will be a strong foundation to help us understand how genomes evolve in response to different environmental challenges.”

Jörns Fickel, Head, Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research