Genetic Surfing, Not Allopatric Divergence, Explains Spatial Sorting Of Mitochondrial Haplotypes In Venomous Coralsnakes

Keywords

Directionality index psi; Elapidae; heterozygosity; mitonuclear discordance; private alleles; RADseq; serial founder effect

Abstract

Strong spatial sorting of genetic variation in contiguous populations is often explained by local adaptation or secondary contact following allopatric divergence. A third explanation, spatial sorting by stochastic effects of range expansion, has been considered less often though theoretical models suggest it should be widespread, if ephemeral. In a study designed to delimit species within a clade of venomous coralsnakes, we identified an unusual pattern within the Texas coral snake (Micrurus tener): strong spatial sorting of divergent mitochondrial (mtDNA) lineages over a portion of its range, but weak sorting of these lineages elsewhere. We tested three alternative hypotheses to explain this pattern-local adaptation, secondary contact following allopatric divergence, and range expansion. Collectively, near panmixia of nuclear DNA, the signal of range expansion associated sampling drift, expansion origins in the Gulf Coast of Mexico, and species distribution modeling suggest that the spatial sorting of divergent mtDNA lineages within M. tener has resulted from genetic surfing of standing mtDNA variation-not local adaptation or allopatric divergence. Our findings highlight the potential for the stochastic effects of recent range expansion to mislead estimations of population divergence made from mtDNA, which may be exacerbated in systems with low vagility, ancestral mtDNA polymorphism, and male-biased dispersal.

Publication Date

7-1-2016

Publication Title

Evolution; international journal of organic evolution

Volume

70

Issue

7

Number of Pages

1435-1449

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1111/evo.12967

Socpus ID

85027954550 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85027954550

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