Is it a mottled duck? The key is in the feathers

Bielefeld, Ronald R.; Engilis, Andrew; Feddersen, Jamie C.; Eadie, John M.; Tringali, Michael D.; Benedict, R. Joseph

doi:10.1002/wsb.665

Cited by 8 publications

(16 citation statements)

References 25 publications

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“…Furthermore, only ~60% of phenotypically identified hybrids were true hybrids with ~12% and ~25% of remaining samples being actually “pure” mallards or black ducks, respectively (Figure , Table ; Supporting Information Table ). Our “error rates” are similar to those reported between mallards and Florida Mottled ducks before a genetically vetted field key was developed (Bielefeld et al, ). With the exception of western mallards, all Mississippi and Atlantic flyway mallards, black ducks, and hybrids were sampled from the 2010 U.S.…”

Section: Discussionsupporting

confidence: 83%

“…For example, the presence of an anterior and/or posterior white‐wing bar across the speculum is currently a primary character used to identify hybrids between mallards and black ducks. However, a recent study found the same character thought to be indicative of hybrids between mallards and mottled ducks in 10% of genetically “pure” mottled ducks (Bielefeld et al, ). Thus, for scenarios of recent divergence in which ancestral characters may be maintained across lineages, it is critical to genetically vet phenotypic characters to confirm their diagnosability.…”

Section: Discussionmentioning

confidence: 98%

“…A recent study that genetically vetted phenotypic traits between mallards, mottled ducks ( A . fulvigula ), and their hybrids reported that a key character used to identify hybrids was in fact found in 10% of genetically “pure” mottled ducks (Bielefeld et al, ), suggesting that at least some of the phenotypic characters may not at all be entirely diagnostic. Thus, assessing genetic assignments will provide important information that will either validate current practices or identify which species‐cohort requires re‐evaluation.…”

Section: Introductionmentioning

confidence: 99%

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Identifying hybrids & the genomics of hybridization: Mallards & American black ducks of Eastern North America

Lavretsky

Janzen

McCracken

2019

Ecology and Evolution

101

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Resolving evolutionary relationships and establishing population structure depends on molecular diagnosability that is often limited for closely related taxa. Here, we use 3,200 ddRAD‐seq loci across 290 mallards, American black ducks, and putative hybrids to establish population structure and estimate hybridization rates. We test between traditional assignment probability and accumulated recombination events based analyses to assign hybrids to generational classes. For hybrid identification, we report the distribution of recombination events complements ADMIXTURE simulation by extending resolution past F4 hybrid status; however, caution against hybrid assignment based on accumulated recombination events due to an inability to resolve F1 hybrids. Nevertheless, both analyses suggest that there are relatively few backcrossed stages before a lineage's hybrid ancestry is lost and the offspring are effectively parental again. We conclude that despite high rates of observed interspecific hybridization between mallards and black ducks in the middle part of the 20th century, our results do not support the predicted hybrid swarm. Conversely, we report that mallard samples genetically assigned to western and non‐western clusters. We indicate that these non‐western mallards likely originated from game‐farm stock, suggesting landscape level gene flow between domestic and wild conspecifics.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Identifying hybrids & the genomics of hybridization: Mallards & American black ducks of Eastern North America

Lavretsky

Janzen

McCracken

2019

Ecology and Evolution

101

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“…Stocks of mottled ducks used in these translocations were composed of 2 subspecies that are distinct in genetics, phenotype, and ecology (Bielefeld et al 2010(Bielefeld et al , 2016Baldassarre 2014;Peters et al 2016). In short, Western Gulf Coast mottled ducks (A. f. maculatlus) are indigenous to coastal marshes surrounding the Gulf of Mexico from Mexico and north and east through Texas, Louisiana, Mississippi, and Alabama, USA.…”

mentioning

confidence: 99%

Population Genetics of a Translocated Population of Mottled Ducks and Allies

et al. 2021

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Translocating species is an important management tool to establish or expand the range of species. Success of translocations requires an understanding of potential consequences, including whether a sufficient number of individuals were used to minimize founder effects and if interspecific hybridization poses a threat. We provide an updated and comprehensive genetic assessment of a 1970s-1980s translocation and now established mottled duck (Anas fulvigula) population in South Carolina, USA. In addition to examining the population genetics of these mottled ducks, we simulated expected genetic assignments for generational hybrids (F1-F10), permitting formal purity assignment across samples to identify true hybrids and establish hybridization rates. In addition to wild mallards (A. platyrhynchos), we tested for presence of hybrids with migrant American black ducks (A. rubripes) and released domestic game-farm mallards (A. p. domesticus). We used wild reference populations of North American mallard-like ducks and sampled game-farm mallards from 2 sites in South Carolina that could potentially interbreed with mottled ducks. Despite 2 different subspecies of mottled duck (Florida [A. f. fulvigula] and the Western Gulf Coast [A. f. maculatlus]) used in original translocations, we determined the gene pool of the Western Gulf Coast mottled duck was overwhelmingly represented in South Carolina's current population. We found no evidence of founder effects or inbreeding and concluded the original translocation of 1,285 mottled ducks was sufficient to maintain current genetic diversity. We identified 7 hybrids, including an F1 and 3 late-staged (i.e., F2-F3 backcrosses) mottled duck × black duck hybrids, 1 F2-mottled duck backcrossed with a wild mallard, and 2 F3-mottled ducks introgressed with gamefarm mallard. We estimated a 15% hybridization rate in our mottled duck dataset; however, the general lack of F1 and intermediate hybrids were inconsistent with scenarios of high hybridization rates or presence of a hybrid swarm. Instead, our results suggested a scenario of infrequent interspecific hybridization between South Carolina's mottled ducks and congeners. We concluded that South Carolina's mottled duck population is sufficiently large now to absorb current hybridization rates because 85% of sampled mottled ducks were pure. These results demonstrate the importance in managing and maintaining large parental populations to counter hybridization. As such, future population management of mottled ducks in South Carolina will benefit from increased geographical and continued sampling to monitor hybridization rates with closely related congeners. We also suggest that any future translocations of mottled ducks to coastal South Carolina should originate from the Western Gulf Coast.

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“…Due to phenotypic variation among sex and age classes in other waterfowl, the use of such characters alone has led to an overestimation of hybridization in some species (Williams et al 2005; e.g. mottled duck × mallard hybridization, Bielefeld et al 2016; Mexican duck × mallard hybridization, Hubbard 1977, Scott and Reynolds 1984). Therefore, while field observations suggest hybridization between goldeneye is rare, overall rates of hybridization and inter‐specific gene flow are still largely unknown.…”

Section: Introductionmentioning

confidence: 99%

High site fidelity does not equate to population genetic structure for common goldeneye and Barrow's goldeneye in North America

Brown

Lavretsky

Wilson

et al. 2020

Journal of Avian Biology

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Delineation of population structure provides valuable information for conservation and management of species, as levels of demographic and genetic connectivity not only affect population dynamics but also have important implications for adaptability and resiliency of populations and species. Here, we measure population genetic structure and connectivity across the ranges of two sister species of sea ducks: Barrow's goldeneye Bucephala islandica and common goldeneye B. clangula. We use two different marker types: 7-8 nuclear microsatellite loci assayed across 229 samples and 3678 double digest restriction-site associated DNA sequencing (ddRAD-seq) loci assayed across 61 samples. First, both datasets found no evidence of genetic structure within common or Barrow's goldeneye, including between North American and European samples of common goldeneye. These results are in contrast with previous mitochondrial DNA, band recovery and telemetry data which suggest that goldeneyes are structured across their range. We posit that the discordance between autosomal genetic markers and other data types suggests that males, possibly subadult males, may be maintaining genetic connectivity across each species' respective ranges. Next, although mate choice consequences resulting from inter-specific brood parasitism was hypothesized to cause some level of gene flow between goldeneye species, we only identified a single F1 hybrid with no further evidence of contemporary or historical gene flow. Despite ddRAD-seq demographic analyses which recovered an optimum evolutionary model of split-with-migration (i.e. secondary contact), estimates of gene flow were <<1 migrant per generation in both directions. Together, we conclude that either strong ecological barriers or assortative mating are likely playing a role in preventing further backcrossing. Finally, demographic analyses estimated a relatively deep divergence time between Barrow's goldeneye and common goldeneye of ~1.6 million years before present and suggests that the genomes of both species have been under similar evolutionary constraints.

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Is it a mottled duck? The key is in the feathers

Cited by 8 publications

References 25 publications

Identifying hybrids & the genomics of hybridization: Mallards & American black ducks of Eastern North America

Identifying hybrids & the genomics of hybridization: Mallards & American black ducks of Eastern North America

Population Genetics of a Translocated Population of Mottled Ducks and Allies

High site fidelity does not equate to population genetic structure for common goldeneye and Barrow's goldeneye in North America

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