Reconciling nuclear microsatellite and mitochondrial marker estimates of population structure: breeding population structure of Chesapeake Bay striped bass (Morone saxatilis)

Abstract

Comparative analyses of nuclear and organelle genetic markers may help delineate evolutionarily significant units or management units, although population differentiation estimates from multiple genomes can also conflict. Striped bass (Morone saxatilis) are long-lived, highly migratory anadromous fish recently recovered from a severe decline in population size. Previous studies with protein, nuclear DNA and mitochondrial DNA (mtDNA) markers produced discordant results, and it remains uncertain if the multiple tributaries within Chesapeake Bay constitute distinct management units. Here, 196 young-of-the-year (YOY) striped bass were sampled from Maryland's Choptank, Potomac and Nanticoke Rivers and the north end of Chesapeake Bay in 1999 and from Virginia's Mataponi and Rappahannock Rivers in 2001. A total of 10 microsatellite loci exhibited between two and 27 alleles per locus with observed heterozygosities between 0.255 and 0.893. The 10-locus estimate of R ST among the six tributaries was À0.0065 (95% confidence interval À0.0198 to 0.0018). All R ST and all but one y estimates for pairs of populations were not significantly different from zero. Reanalysis of Chesapeake Bay striped bass mtDNA data from two previous studies estimated population differentiation between y ¼ À0.002 and 0.160, values generally similar to mtDNA population differentiation predicted from microsatellite R ST after adjusting for reduced effective population size and uniparental inheritance in organelle genomes. Based on mtDNA differentiation, breeding sex ratios or gene flow may have been slightly male biased in some years. The results reconcile conflicting past studies based on different types of genetic markers, supporting a single Chesapeake Bay management unit encompassing a panmictic striped bass breeding population. Heredity (2005) 94, 606-615.

Assessment of Genetic Divergence between Lacustrine and Riverine Smallmouth Bass in Lake Erie and Four Tributaries

“…For example, the small mtDNA divergence of Smallmouth Bass between the Cuyahoga and Chagrin Rivers is contradicted by a very large and statistically significant nDNA microsatellite divergence (Stepien et al 2007). However, discordance between mitochondrial and nuclear markers is not uncommon (e.g., Brown et al 2005, Canestrelli et al 2007). The distribution of genetic variation within a single river was not evaluated, but resident-stream Smallmouth Bass possess variable migratory behaviors within and among rivers (Lyons and Kanehl 2002, Paragamian and Coble 1975, Reynolds 1965, which may have contributed to this discrepancy.…”

Post-mating reproductive barriers in two unidirectionally hybridizing sunfish (Centrarchidae: Lepomis)

“…Genotyping of PCR amplifications was performed at the Georgetown University Sequencing Laboratory using procedures detailed elsewhere (Brown et al. , 2003, 2005).…”

Identification of conservation units in the European Mergus merganser based on nuclear and mitochondrial DNA markers

“…Contrasting levels of genetic differentiation among populations based on nuclear and mitochondrial loci are detected in many species (e.g. Johnson et al 2003;Chappell et al 2004;Gay et al 2004;Brown et al 2005;Jones et al 2005). There are several explanations for this phenomenon.…”