Wir bitten um Entschuldigung
Presseinformation: Sudden complexity just 65 million years ago
Nr. 162 - 29.10.2025
Research team led by Göttingen University study genetic evolution of alga
Land plants – such as mosses, ferns and trees – are some of the most structurally complex photosynthesizing organisms on Earth. But their evolutionary story is deeply tied to their ancestors: simpler green algae that lived hundreds of millions of years ago. Among these algae, a group related to land plants that can still be found today – the Coleochaetophyceae – stands out. These freshwater algae form branching, disc-shaped structures that resemble some of the building blocks of plants’ bodies. Interestingly, the closest living algal relatives of land plants – the Zygnematophyceae – are much simpler in structure, suggesting that plant-like complexity appeared and disappeared multiple times throughout evolution. Now, an international team of researchers led by the University of Göttingen has used DNA and data from fossil evidence to shed new light on this enigmatic group of algae: Coleochaetophyceae. The results were published in Current Biology.
By studying the genes of Coleochaetophyceae, many of which were cultivated and obtained from the Culture Collection of Algae at the University of Göttingen (SAG), and comparing it with fossil evidence, the scientists estimated that this group originated over 600 million years ago, long before the first land plants. Within the group, there are subgroups such as the genus Coleochaete which itself dates back over 400 million years. Yet, the more complex disc-shaped forms, such as Coleochaete scutata, only appeared about 65 million years ago – relatively recently in evolutionary terms. “This tells us that we need to sample a broad diversity of ancient lineages to understand the evolution of complex traits such as body plans,” explains Professor Jan de Vries at Göttingen University’s Institute of Microbiology and Genetics. “The fact that the closest living relatives – the Zygnematophyceae – are much simpler means that body complexity wasn’t a one-off evolutionary gain: it happened over and over again at different times in different lineages.”
When they analysed the sequences, researchers found that Coleochaetophyceae shared many of the same growth-regulating genes with land plants, including those linked to cell division and plant hormones like cytokinin, which is crucial for processes like cell division and shoot and root growth. However, to date no single set of genes appears to explain why some species grow just as simple filaments while others form more elaborate disc-shaped bodies. This suggests that complexity doesn’t just depend on having the right genes but also on when and how those genes are turned on. “Our findings highlight that plant-like complexity is an ancient potential,” adds first author Maaike Bierenbroodspot, also at Göttingen University’s Institute of Microbiology and Genetics. “This means that sometimes the genes were there in the DNA already until their actions were newly wired over the course of evolution for instance in algae and land plants.”
Original publication: Bierenbroodspot MJ et al, “Phylogenomics unveil recent origin of morphological complexity in Coleochaetophyceae” Current Biology 2025. DOI: 10.1016/j.cub.2025.08.046
Contact:
Professor Jan de Vries
University of Göttingen
Faculty of Biology and Psychology
Institute of Microbiology and Genetics
Department of Applied Bioinformatics
37077 Göttingen, Germany
Tel: +49 (0)551 39-13995