Behind the Cover: New Phytologist 214:4, June 2017

The image on the cover of New Phytologist 214:4 shows Diplostephium cinereum, a species that inhabits the high elevations (3900–4600 m) of Peru, Bolivia, and Chile.

Hamilton Beltrán, a collaborator with lead author Oscar Vargas, took the picture near the province of Yauyo in central Peru at an elevation of 4500 m.

I caught up with Oscar to find out some more details about the paper behind the cover.

Image: Diplostephium cinereum, a high‐Andean species that has a strong signal of introgression with a congener. Courtesy of Hamilton Beltrán.
Diplostephium cinereum, a high‐Andean species that has a strong signal of introgression with a congener. Courtesy of Hamilton Beltrán.

What was the aim of your research?

Oscar: In a broad sense, I am interested in understanding the origin of species in regions with high biodiversity. I am particularly interested in the Andean mountains and the Amazon basin. By inferring the evolutionary relationships of groups of plants with high numbers of species using DNA, I intend to test hypotheses about the evolution of such groups.

How does this image contribute to the results in your paper?

The paper published in the New Phytologist tested the hypothesis of common hybridization among different species in a group of plants that have recently evolved in the Andes.

We were able to find a high genetic signature of recent and ancestral hybridization in many of the plants included in the study. I thought that in addition to showing the genetic results in the paper, it would be a good idea to show pictures of species involved in these processes of interspecific genetic flow.

Image: A photo taken in the Andes, near Ecuador. Courtesy of Oscar Vargas.
A photo taken in the Andes, near Ecuador. Courtesy of Oscar Vargas.

It turns out that there is a group of four species from the Peruvian Andes that all have high marks of hybridization among them. Diplostephium cinereum, the plant pictured on the cover, is one of those plants, as it has high indices of gene flow with Diplostephium meyenii or Parastrephia quadrangularis. We also included a portrait of an undescribed species, referred to in the paper as Diplostephium sp. nov. CAJ 2, which we believe is the product of a hybridization between Diplostephium meyenii and Parastrephia quadrangularis.

Image: Figure 4 from Vargas et al. (2017): Photos of taxa with high genetic hybridization signal. (a) Parastrephia quadrangularis; (b) Diplostephium meyenii; (c) Diplostephium sp. nov. CAJ2; and (d) Diplostephium cinereum. Notice the hybrid morphology of Diplostephium sp. nov. CAJ2 in relation to P. quadrangularis and D. meyenii.
Figure 4 from Vargas et al. (2017): Photos of taxa with high genetic hybridization signal. (a) Parastrephia quadrangularis; (b) Diplostephium meyenii; (c) Diplostephium sp. nov. CAJ2; and (d) Diplostephium cinereum. Notice the hybrid morphology of Diplostephium sp. nov. CAJ2 in relation to P. quadrangularis and D. meyenii.

The photo of Diplostephium sp. nov. CAJ 2 shows striking signs of hybrid morphology. I believe the figure, with the four species pictured, greatly improves the assimilation of information by presenting the reader with a visual example of the process we describe in the paper.

Read the paper: Vargas, O. M., Ortiz, E. M. and Simpson, B. B. (2017) Conflicting phylogenomic signals reveal a pattern of reticulate evolution in a recent high-Andean diversification (Asteraceae: Astereae: Diplostephium). New Phytologist, 214: 1736–1750. doi: 10.1111/nph.14530

Mike Whitfield
Development Coordinator
New Phytologist

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