He wants to spread knowledge about vital diversity


9 september 2021

Man in front of garden

"We need to understand why species arise and die out, and we need to understand why this crisis has arisen right now in order to do something about it," says biologist Jacob Höglund.

For Jacob Höglund, Professor of Animal Conservation Biology, there is no issue more important than the extinction of species and the fact that we are currently losing more species than are evolving. “As I see it, the sixth mass extinction is very most important issue facing humanity.”

Although biodiversity may previously have been side-lined in reports on climate change, awareness of the furious pace at which animal species are disappearing from the face of the Earth is growing. Unlike during previous ages, the biodiversity crisis is not the result of volcanic eruptions, impact events such as asteroid strikes or natural evolution,” explains Jacob Höglund. Instead, for the first time in history many species are being wiped out by humans, and breaking this negative spiral ought to be our top priority.

“Nothing – not COVID-19 nor cancer research nor going to the Moon – comes even close to this. We need to understand why species arise and die out, and we need to understand why this crisis has arisen right now in order to do something about it. Otherwise, it will have draconian effects,” says Jacob Höglund.

Fateful words. However he also has in-depth insights into the affected fields of ecology, species identification, evolution and genomics. For a long time, his focus has been on genetic diversity. His research group is part of the Evolutionary Biology Centre and specialises in genetic variation in natural populations and how populations can adapt to local changes.

One of the research group’s projects relates to the parasitic fungus Batrachochytrium dendrobatidis, which infects amphibians. During the 1950s, the fungus came with the African clawed frog from South Africa to Korea, where the frog was used for pregnancy testing during the Korean War. This parasitic fungus later spread throughout the world and was discovered in Sweden in 2010. Jacob Höglund’s research group then succeeded in mapping the fungus to determine the extent of its spread – all the way to Norduppland.

“Although the fungus has not killed off Swedish frog populations, it does have a negative impact and increases mortality. It also affects growth and the ability of the animals to find hibernation sites. And because frogs are also subject to other threats such as drainage and agricultural methods, the fungus constitutes an additional stress factor,” says Jacob Höglund.

Green-spotted frog.
Illustration: Olga Vinnere Pettersson

Based on all the frog species observed by the researchers since 2016, they have been able to conclude that genetic diversity is declining in frog populations from south to north. And this means that northern populations are less resistant. The less variation there is, the less likely it is that individuals will have the necessary immune system genes to deal with the infection.

“It’s conceivable that there is a genetically determined resistance to various diseases. As in the case of COVID-19, some people are more vulnerable and others less so. If a population has lots of different genetic variants within it, then there will be some individuals that die. But if it also includes resistant individuals, the population will survive; this is natural selection.”

Regardless of whether we are talking about diseases or environmental changes, the incidence of genetic variation is crucial. According to Jacob Höglund, this makes it possible for a species to adapt to changing conditions. But what can be done in purely practical terms to reverse this trend at a genetic level? His experience is that it is difficult to implement theoretical knowledge in nature conservation efforts in practice. Opinions diverge on everything from the focus of research studies to how genotype data should be interpreted and processed.

“Those of us who are out digging in the woods and wilds and those of us who are working in the lab need to meet somewhere and discuss how we can utilise each other’s knowledge. How can this be done so that it doesn’t end up being university research versus nature conservation in practice, but instead these two being brought together in some way?”   

Jacob Höglund gives a common example: normally, individuals are moved from an endangered population to another population to boost genetic variation and the number of individuals in the population. However, there is always a risk associated with introducing something that is not adapted to the new environment. The solution can be to investigate the genetics of both populations before the move takes place.

“If you study in more detail how genetically similar these populations are, then you can better understand what the consequences of any moves might be. If you have a population in captivity, as in the case of the Nordens Ark zoo, where they seek to save and preserve endangered animals, you can see whether the population adapts to captivity and whether it is even possible to release individuals back into the wild.”

Back in the day when his passion for nature was first ignited, Jacob Höglund became a field biologist and spent long periods observing grouse and great snipes and collecting toads in the field. However, even during his days as a doctoral student, he began to use genetics methods to study ecological questions, and then drifted more and more into lab work.

Today, his dream project is to combine preservation projects with genomics, which is the subject of an application Jacob Höglund has just submitted to the European Research Council. There is stiff competition for EU funding. However, awareness is increasing of the importance of reconciling the differences between what happens at a genetic level and what happens in nature. This is also reflected in the interest in genetic monitoring which involves monitoring genetic variation in different populations. Recently, one of Jacob Höglund’s former doctoral students at the Swedish Environmental Protection Agency published a report containing proposals for monitoring programmes to survey whether genetic variation exists, and signs of fragmentation or reduction in variation, and of inbreeding.

The access to infrastructure given to Jacob Höglund’s research group by SciLifeLab has enabled them to carry out projects that were previously very time- and resource-intensive.  

“Now I can sequence the entire genome of all the organisms I am studying at a fairly reasonable price. Right now, I am involved in quite a large trial to link together reference genomes for endangered species across Europe in order to try and sequence at least one as part of the Earth BioGenome Project. The goal is to collect the reference genomes of all species in a European Reference Genome Atlas. This will allow us to carry out population genomics studies. These data are linked to the reference genome in order to find out exactly which part of the genome is affected by climate change. There is a lot of enthusiasm around this.”

However, visualising abstract concepts such as genes is challenging, not to mention boosting knowledge and engagement around genetic and biological diversity. Jacob Höglund believes that metaphors can help.

“I usually talk about that box you have at home full of nuts and bolts and paper clips and other bits and bobs that are useful to have. And all of a sudden you need one of those things to fix something. So off you go to that box and there’s lots of different things in there – all sorts of stuff – so you’re probably going to be able to fix the problem. But if your box only contains one type of nut or bolt, you haven’t got a hope of fixing it.”


Age: 63.
Title: Professor of Animal Conservation Biology.
Education: Degree of Doctor in Zooecology, 1989, Uppsala University.
Lives: Uppsala.
Family: Yes, wife and four grown-up children.
About my choice of career: My brother and father are biologists, as is my father’s uncle. We three generations of Höglunds have all publicly defended a doctoral thesis in Biology right here in Uppsala. When people ask this question, I usually say it’s because I have no imagination! But animals and nature, ecology, genetics and evolution are such wonderful things to work with.
If I hadn’t become a researcher: Probably would have been a terrible drummer in a rock band or a lousy violinist.
Hidden talent: I build nyckelharps. A nyckelharp is a kind of keyed fiddle similar to a hurdy-gurdy but bowed not hand-cranked to produce the sound. It’s a traditional Swedish musical instrument. I think it’s fun to work with your hands. The nyckelharp is part of our cultural heritage in Sweden and I think they are beautiful. I sold one just a few months ago, and I think that must be the sixth or seventh instrument I have built.
Listens to: Folk music and rock.
Reading: “The Mirror and the Light” by Hilary Mantel.
Most proud of: My two books (Leks, Princeton University Press 1995 and Evolutionary Conservation Genetics, Oxford University Press 2009).
Least proud of: That I can be absent-minded and forget important things.
On Uppsala: The best city!!
Dream trip: Goodness knows, I’ve been almost everywhere – but never to New Guinea.