Published: 4.9.2025
Text: Matti T. Heino
Editing: Viestintätoimisto Jokiranta Oy

Mitochondria are the power generators of eukaryotic cells, providing them with energy. They regulate, for example, cell metabolism, ageing, stress responses, the metabolism of reactive oxygen species (ROS) and cell death. Thus, the functional features of mitochondria are critical in terms of an organism’s ability to respond to environmental challenges like changes in temperature or the availability of food.

Mitochondria have a genome of their own that encodes the components that are crucial for the cell energy supply, such as electron transport chain proteins, endogenous ribosomal RNA molecules and transfer RNA molecules. While the majority of proteins required by the mitochondria are produced from the genes located in the cell nucleus, the endogenous DNA of the mitochondria facilitates a rapid and local response to the energy demands and distress of the cell.

The causes of extinction still remain a topical issue

During the latest glacial period known as the Ice Age and the subsequent Holocene epoch, a considerable number of large animal species living in the Northern hemisphere have either died out or the geographical distribution of their genetic lineage has changed significantly. Examples of extinct species include the woolly mammoth (Mammuthus primigenius), the Neanderthals (Homo neanderthalensis), the cave lion (Panthera spelaea) and the woolly rhinoceros (Coelodonta antiquitatis). Some surviving species, such as bison (Bison spp.) and the Finnish forest reindeer (Rangifer tarandus fennicus), experienced significant genetic alterations or population variation during these eras.

The underlying causes – whether due to climate changes or human impacts or a combination of both – are still topical issues in the scientific discourse. The waves of extinction fluctuated chronologically and geographically, which suggests that the fates of different species were influenced by numerous complex and species-specific factors, such as changing habitats, food web disturbances and the genetic diversity of populations. The analyses of fossil and ancient DNA materials have, in recent years, shed light on these processes from a new angle, but the exact underlying causes still remain a mystery for several species.

New information on the adaptability of organisms

The aim of my research is to investigate whether the features of mitochondrial genomes have affected which animal species or genetic lines survived and which became extinct, and if these features explain the current distribution of genetic lineage. Possible genetic mutation mechanisms are another topic of interest in my research.

The research is mostly based on open-access materials and calculation tools. Mitochondrial genome sequences for both extinct and currently living species are obtained from the GenBank and climatic variables from the CHELSA data base. Scientific publications provide details concerning biological properties, such as body size and lifetime. My intention is to use these data materials and develop generalised linear mixed models (GLMMs), including a phylogenic correction, for the purpose of quantifying the association between the mitochondrial genome features and the characteristics of particular species.

I hope that my research will enhance our knowledge about the ability of organisms to adapt to their environment. Also, it would be great if the results of my research could be utilised for the identification of those species and populations that are particularly at risk of becoming extinct along with the progressing climate change.

 

 

PhD Matti T. Heino is an evolutionary geneticist who is currently working as Postdoctoral Researcher in the PaleOmics Laboratory, led by Professor Antti Sajantila, within the Department of Forensic Medicine, University of Helsinki. In his research, Heino focuses on the adaptation of organisms to varying environmental circumstances, the mechanisms of genetic mutations and the study of ancient DNA.

 

Main image of the blog post: Woolly mammoth and reindeer. Image created by the author using Microsoft Copilot AI, 2025.