Dataset Information

Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species.

ABSTRACT: Morphologically similar species, that is cryptic species, may be similar or quasi-similar owing to the deceleration of morphological evolution and stasis. While the factors underlying the deceleration of morphological evolution or stasis in cryptic species remain unknown, decades of research in the field of paleontology on punctuated equilibrium have originated clear hypotheses. Species are expected to remain morphologically identical in scenarios of shared genetic variation, such as hybridization and incomplete lineage sorting, or in scenarios where bottlenecks reduce genetic variation and constrain the evolution of morphology. Here, focusing on three morphologically similar Stygocapitella species, we employ a whole-genome amplification method (WGA) coupled with double-digestion restriction-site associated DNA sequencing (ddRAD) to reconstruct the evolutionary history of the species complex. We explore population structure, use population-level statistics to determine the degree of connectivity between populations and species, and determine the most likely demographic scenarios which generally reject for recent hybridization. We find that the combination of WGA and ddRAD allowed us to obtain genomic-level data from microscopic eukaryotes (?1 millimetre) opening up opportunities for those working with population genomics and phylogenomics in such taxa. The three species share genetic variance, likely from incomplete lineage sorting and ancient admixture. We speculate that the degree of shared variation might underlie morphological similarity in the Atlantic species complex.

SUBMITTER: Cerca J

PROVIDER: S-EPMC7879940 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species.

Cerca José J Rivera-Colón Angel G AG Ferreira Mafalda S MS Ravinet Mark M Nowak Michael D MD Catchen Julian M JM Struck Torsten H TH

PeerJ 20210209

Morphologically similar species, that is cryptic species, may be similar or quasi-similar owing to the deceleration of morphological evolution and stasis. While the factors underlying the deceleration of morphological evolution or stasis in cryptic species remain unknown, decades of research in the field of paleontology on punctuated equilibrium have originated clear hypotheses. Species are expected to remain morphologically identical in scenarios of shared genetic variation, such as hybridizati ...[more]

PMID: 33614296

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Project description:Abstract A cryptic lineage is a genetically diverged but morphologically unrecognized variant of a known species. Clarifying cryptic lineage evolution is essential for quantifying species diversity. In sympatric cryptic lineage divergence compared with allopatric divergence, the forces of divergent selection and mating patterns override geographical isolation. Introgression, by supplying preadapted or neutral standing genetic variations, can promote sympatric cryptic lineage divergence via selection. However, most studies concentrated on extant species introgression, ignoring the genetic legacy of introgression from extinct or unsampled lineages (“ghost introgression”). Cycads are an ideal plant for studying the influence of ghost introgression because of their common interspecific gene flow and past high extinction rate. Here, we utilized reference‐based ddRADseq to clarify the role of ghost introgression in the evolution of a previously identified sympatric cryptic lineage in Cycas revoluta. After re‐evaluating the evolutionary independency of cryptic lineages, the group‐wise diverged single‐nucleotide polymorphisms among sympatric and allopatric lineages were compared and functionally annotated. Next, we employed an approximate Bayesian computation method for hypothesis testing to clarify the cryptic lineage evolution and ghost introgression effect. SNPs with the genomic signatures of ghost introgression were further annotated. Our results reconfirmed the evolutionary independency of cryptic lineage among C. revoluta and demonstrated that ghost introgression to the noncryptic lineage facilitated their divergence. Gene function related to heat stress and disease resistance implied ecological adaptation of the main extant populations of C. revoluta. Previous population genetics study revealed a sympatric cryptic lineage of Cycas revoluta in Taiwan. By detecting the SNP outliers and annotating its functions of lineages sympatric and allopatric to the cryptic lineage, plus approximate Bayesian computation model selection, this article provided a mechanism of the sympatric cryptic lineage divergence by ghost introgression.

Dataset Information

Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species.

Publications

Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species.

Similar Datasets

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