Marcos Vinicius Dantas-Queiroz is a PhD from the São Paulo State University in Brazil. He is a botanist interested in linking microevolutionary processes to macroevolutionary patterns. Here, Marcos shares his recent work on the phylogeography of ancient neotropical mountains.
Marcos Vinicius Dantas-Queiroz during lab work.
Institute. São Paulo State University (Rio Claro campus), Department of Ecology
Academic life stage. PhD
Major research themes. Plant Evolution | Phylogeography | Bioinformatics | Biogeography | Ecology
Current study system. I’m currently studying one of the most biodiverse ecosystems of the world: the campos rupestres, a unique vegetation with more than 2,000 endemic plant species mainly found in Eastern Brazil. The campos rupestres is composed of xerophytic vegetation, dominated by herbaceous and shrubby species well-adapted to harsh conditions since most of the soils in the area are shallow and well-drained with intense solar radiation and a striking daily temperature variation. Under a phylogeographic approach, I’m trying to unveil the evolutionary dynamics that generated such an amazing biota.
Recent JBI paper. Dantas-Queiroz, M.V.; Cacossi, T.C.; Leal, B.S.S.; Chaves, C.J.N.; Vasconcelos, T.N.; Versieux, L.M. & Palma-Silva, C. 2021. Underlying microevolutionary processes parallel macroevolutionary patterns in ancient neotropical mountains. Journal of Biogeography, 48(9): 2312-2327 doi.org/10.1111/jbi.14154
The vegetation known as campos rupestres is mainly found in Eastern Brazil. This picture is from Rio de Contas, in Chapada Diamantina, Bahia, Brazil.
Motivation behind this paper. How can one link the microevolutionary processes that generate macroevolutionary patterns? Visualizing the effects of microevolutionary processes in already diverged lineages may be challenging. Still, it might be possible to observe these first steps of speciation in extant species with structured populations. Thus, we selected a species widely distributed but endemic to the campos rupestres, the bromeliad Vriesea oligantha, as a model system to investigate how its populations are structured and which factors probably generated this pattern. With this approach, we provided insights into how the macroevolutionary patterns of this vegetation originated.
Key methodologies. Our paper relies mainly on two analyses: ecological niche modeling and population genetic simulation models using Approximate Bayesian Computing (ABC). We hypothesized that past climatic fluctuations strongly interfered with the population dynamics of this bromeliad. We tested for demographic expansion with genetic markers and, with niche modeling, for suitable areas over time. By uniting the two approaches, we found that both corroborate an expansion scenario in the past. We were able to demonstrate that, in fact, the climatic fluctuations of the last thousands of years, mainly during the Last Glacial Maximum, had a great role in the population dynamics of this species and is possibly a strong evolutionary driver for the entire community.
The bromeliad Vriesea oligantha, the model of my study. This species is endemic but widespread in the Espinhaço, an Eastern South American mountain range.
Unexpected challenges. An inherent problem of bromeliads is the low level of polymorphism in their genetic markers. So, revealing the genetic structure and demographic patterns of V. oligantha was challenging. Using “classical” demographic analyses (e.g., Tajimas’s D, Fu’s F), we could not get much information. Fortunately, with more robust and computationally more intensive analyses, such as the ABC simulations we performed, we untangled the population history of V. oligantha, demonstrating that even with Sanger sequencing technology, it is possible to have positive insights when elucidating the natural history of tropical species.
Major results. We showed that microevolutionary processes are a proxy for understanding macroevolutionary patterns. In our paper, we suggest that continuous cycles of climate changes in the Pleistocene might be key factors for understanding evolutionary responses (speciation, extinction, migration and adaptation) due to the continuous cycles of connectivity and disconnection amongst populations. Considering the assumption that population differentiation is the primary mechanism of speciation, the concordant pattern between V. oligantha population divergence and the biogeography of the Eastern Brazilian mountains generated powerful insights into how climatic variables and limited gene flow might have shaped early stages of macroevolutionary patterns in the region.
An overview of the Espinhaço Range. The peak on the left is known as Pico das Almas (Bahia), one of the highest points of the Espinhaço (1958 m).
Next steps for this research. Our next step is to incorporate more organisms into a comparative phylogeographic approach. Thus, additional evidence using distinct organisms with independent evolutionary histories and divergent ecological traits could provide contrasting examples of how microevolutionary processes act and translate into the current biogeographic patterns of tropical montane biotas.
If you could study any organism on Earth, what would it be? I’m a Brazilian botanist, so I am privileged to have been born and grew up in a tropical country. However, In 2018 I had the opportunity to visit the Pacific West Coast, where I fell in love with the Sequoia forests, a sacred place for any biophile. Thus, if I could study a single organism, that would be the amazing Sequoia trees! I would like to understand its complete evolutionary history while also working with conservation policies and strategies to save this species and the astonishing landscapes where it lives.