Divergent mitochondrial lineages arose within a large, panmictic population of the Savannah sparrow (Passerculus sandwichensis)

Phred M. Benham, Zachary A. Cheviron

Research output: Contribution to journalArticlepeer-review

Abstract

Unusual patterns of mtDNA diversity can reveal interesting aspects of a species’ biology. However, making such inferences requires discerning among the many alternative scenarios that could underlie any given mtDNA pattern. Next-generation sequencing methods provide large, multilocus data sets with increased power to resolve unusual mtDNA patterns. A mtDNA-based phylogeography of the Savannah sparrow (Passerculus sandwichensis) previously identified two sympatric, but divergent (~2%) clades within the nominate subspecies group and a third clade that consisted of birds sampled from northwest Mexico. We revisited the phylogeography of this species using a population genomic data set to resolve the processes leading to the evolution of sympatric and divergent mtDNA lineages. We identified two genetic clusters in the genomic data set corresponding to (a) the nominate subspecies group and (b) northwestern Mexico birds. Following divergence, the nominate clade maintained a large, stable population, indicating that divergent mitochondrial lineages arose within a panmictic population. Simulations based on parameter estimates from this model further confirmed that this demographic history could produce observed levels of mtDNA diversity. Patterns of divergent, sympatric mtDNA lineages are frequently interpreted as admixture of historically isolated lineages. Our analyses reject this interpretation for Savannah sparrows and underscore the need for genomic data sets to resolve the evolutionary mechanisms behind anomalous, locus-specific patterns.

Original languageEnglish
Pages (from-to)1765-1783
Number of pages19
JournalMolecular Ecology
Volume28
Issue number7
DOIs
StatePublished - Apr 2019

Keywords

  • Passerculus
  • Passerellidae
  • genotyping-by-sequencing
  • mitochondrial DNA
  • phylogeography

Fingerprint

Dive into the research topics of 'Divergent mitochondrial lineages arose within a large, panmictic population of the Savannah sparrow (Passerculus sandwichensis)'. Together they form a unique fingerprint.

Cite this