Using natural history to guide supervised machine learning for cryptic species delimitation with genetic data

Frontiers in Zoology

Marshal Hedin¹  James Starrett²  Shahan Derkarabetian³ 

[1] Department of Biology, San Diego State University, 5500 Campanile Drive, 92182-4614, San Diego, CA, USA;Department of Entomology and Nematology, University of California, Davis, Briggs Hall, 95616-5270, Davis, CA, USA;Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, 26 Oxford St., 02138, Cambridge, MA, USA;

关键词: Integrative taxonomy;    Multispecies coalescent;    RADSeq;    Short-range endemism;    Southern Appalachians;    Supervised machine learning;    Ultraconserved elements;   

DOI  :  10.1186/s12983-022-00453-0

来源: Springer

【 摘 要 】

The diversity of biological and ecological characteristics of organisms, and the underlying genetic patterns and processes of speciation, makes the development of universally applicable genetic species delimitation methods challenging. Many approaches, like those incorporating the multispecies coalescent, sometimes delimit populations and overestimate species numbers. This issue is exacerbated in taxa with inherently high population structure due to low dispersal ability, and in cryptic species resulting from nonecological speciation. These taxa present a conundrum when delimiting species: analyses rely heavily, if not entirely, on genetic data which over split species, while other lines of evidence lump. We showcase this conundrum in the harvester Theromaster brunneus, a low dispersal taxon with a wide geographic distribution and high potential for cryptic species. Integrating morphology, mitochondrial, and sub-genomic (double-digest RADSeq and ultraconserved elements) data, we find high discordance across analyses and data types in the number of inferred species, with further evidence that multispecies coalescent approaches over split. We demonstrate the power of a supervised machine learning approach in effectively delimiting cryptic species by creating a “custom” training data set derived from a well-studied lineage with similar biological characteristics as Theromaster. This novel approach uses known taxa with particular biological characteristics to inform unknown taxa with similar characteristics, using modern computational tools ideally suited for species delimitation. The approach also considers the natural history of organisms to make more biologically informed species delimitation decisions, and in principle is broadly applicable for taxa across the tree of life.

【 授权许可】

CC BY