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T.L. King

Publications and source records attributed to T.L. King.

At least 37 records · Page 2Linked to original sources
USGS2005

Molecular identification of cypripedioid orchids in international trade

Two cypripedioid orchid genera, Paphiopedilum and Phragmipedium, are listed in Appendix I of CITES and are restricted from international trade. Because of their morphological similarity to other genera, however, they may be disguised as belonging to one of the other cypripedioids listed along with other orchids in Appendix II of CITES. Sequence analysis was performed on the internal transcribed spacer region (ITS) of ribosomal DNA of cypripedioid orchids to develop a molecular marker system capable of discriminating among rare species in trade. Molecular analyses concentrated on rare cypripedioid orchids from the genera Paphiopedilum and Phragmipedium, which are known to be poached from the wild and smuggled across international borders disguised as common species. A total of 48 taxa representing two genera {Paphiopedilum, N = 43; Phragmipedium, N = 5) have been sequenced and compared for distinc- tiveness. Phylogenetic analyses clearly distinguish between these two genera and among other cypripedioid genera, with 5-10 fixed nucleotide differences reported between genera. Within a genus, sections of closely related taxa are recoverable in phylogenetic analyses, in most cases, with low sequence divergence within sections. ITS sequences available in GenBank have been aligned with data generated for this project, resulting in a comprehensive sequence library of 151 sequences representing all genera of cypripedioid orchids: 70 Paphiopedilum taxa, 16 Phragmipedium taxa, and 14 Cypripedium taxa, as well as represen- tatives from Selenipedium and the monotypic genus Mexipedium (Phragmipedium) xerophyticum. Addi- tionally, several organelle intron regions have been screened for variation among genera and species. Both the chloroplast řrnS-M and the mitochondrial NAD1 intron regions, which varied between genera in nu- cleotide substitutions and indels, hold promise for increasing ability to distinguish between these orchids. The set of DNA markers examined for this project are diagnostic of these genera, appear to be robust, and are suitable for rapid assay to avoid unnecessary complication in the legitimate trade of orchids listed in CITES Appendix

Selbyana↗
USGS2004

Comparison of genetic diversity in the recently founded Connecticut River Atlantic salmon population to that of its primary donor stock, Maine's Penobscot River

Anadromous Atlantic salmon returning to the Connecticut River (CR) from 1996 to 1999 were assayed for variability at nine microsatellite DNA loci. Heterozygosity and allele frequencies were compared to the anadromous Atlantic salmon returning to Maine's Penobscot River from 1998 to 2000. The Penobscot River was the primary source of the salmon used to found the previously extirpated population in the Connecticut River. While there were no significant differences in heterozygosity between the source population and the Connecticut River sea-run spawners, microsatellite allele frequencies were significantly different between the populations. Two techniques of estimating effective population size (Ne) suggested a healthy level of genetic variation in the Connecticut River population of anadromous Atlantic salmon. This is significant because the sea-run population is maintained almost entirely through hatchery production. Healthy ratios of Ne to N indicate that hatchery production has not resulted in excessive inbreeding to date. ?? 2003 Elsevier B.V. All rights reserved.

Aquaculture↗
USGS2003

Population structure of Atlantic salmon in Maine with reference to populations from Atlantic Canada

Anadromous Atlantic salmon Salmo salar from 12 rivers in Maine, 3 rivers in New Brunswick, and 2 rivers each in Nova Scotia, Quebec, Newfoundland, and Labrador as well as 2 landlocked strains in Maine ( N = 3,863) were genotyped at 11 microsatellite loci. Fish in the drainages of Maine's Kennebec and Penobscot rivers were genetically similar to those sampled from the 8 rivers recently listed as containing an endangered distinct population segment under the United States' Endangered Species Act. Genetic distance estimates confirm that Maine's Atlantic salmon, both landlocked and anadromous, represent a discrete population unit, genetically as independent from any Canadian population as the Canadian populations are from each other. Within Maine, the anadromous and landlocked populations were statistically distinct. Anadromous Atlantic salmon were more genetically similar among year-classes within rivers than among rivers, as would be expected if the river is the unit of population. The effective number of breeders estimated within each river is larger than the number of adults estimated from samples and redd counts over the 10-year period from 1991 to 2000.

Maine↗
USGS2002

Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): Conservation implications of range discontinuity

A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona , as represented by the four species surveyed in this study, may not be monophyletic.

Delaware, Maryland, North Carolina, Pennsylvania, ↗
USGS2001

Microsatellite DNA markers for the study of Allegheny woodrat (Neotoma magister) populations and cross-species amplification the genus Neotoma

The Allegheny woodrat ( Neotoma magister ) is a colony-forming murid rodent inhabiting rock outcrops, cliff and talus slopes, and caves within the Central and Southern Appalachians of North America ( Hall 1981 ). The species is currently considered threatened, endangered, or at risk throughout its range purportedly due to the direct or indirect effects of human-fragmented landscapes. Currently, Allegheny woodrat management units are arbitrarily defined as metapopulations that roughly constitute contiguous rock outcrops interconnected by forested habitat. To strengthen long-term population stability and reduce the need for further protection through the regulatory process, an effective conservation programme for this at-risk species will require unambiguous, objectively defined units of management that discern evolutionarily important lineages ( Avise 1994 ). A prerequisite in the development of management strategies that recognize and maintain significant woodrat lineages is a thorough understanding of the levels of gene exchange among geographically proximate and distal populations. However, no information exists on population structure, levels of gene flow, or relatedness among Allegheny woodrat populations or colonies. As an initial step towards addressing this research need, we have developed a suite of polymorphic microsatellite DNA markers for this species. In this paper, we describe the isolation and characterization of these markers and demonstrate their suitability in amplifying putatively homologous products in seven additional Neotoma species.

Alabama, Georgia, Kentucky, Mississippi, North Car↗
USGS2001

Population structure of Atlantic salmon (Salmo salar L.): A range-wide perspective from microsatellite DNA variation

Atlantic salmon ( n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south-central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5–37/locus) range-wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum-likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available.

Maine, New Bruinswick, Newfoundland and Labrador, ↗
USGS2001

Fine-scale population structure Atlantic salmon from Maine's Penobscot River drainage

We report a survey of microsatellite DNA variation in Atlantic salmon from the unimpounded lower reaches of Maine's Penobscot River. Our analysis indicates that Atlantic salmon in the Penobscot River are distinct from other populations that have little or no history of human-mediated repopulation, including two of its tributaries, Cove Brook and Kenduskeag Stream, another Maine river, the Ducktrap, and Canada's Miramichi and Gander rivers. Significant heterogeneity was detected in allele frequency among all three subpopulations sampled in the Penobscot drainage. The high resolution of the 12-locussuite was quantified using maximum likelihood assignment tests, which correctly identified the source of 90.4–96.1% of individuals from within the Penobscot drainage. Current populations are clearly isolated from each other, however we are unable to determine from the present data whether the populations in Cove Brook and Kenduskeag Stream are recently diverged from populations stocked into the Penobscot River over the last century, or are aboriginal in origin. The degree of population structure identified in the Penobscot drainage is noteworthy in light of its lengthy history of systematic restocking, the geographic proximity of the subpopulations, and the extent of the differentiation. Similar population structure on this extremely limited geographic scale could exist among Atlantic salmon runs elsewhere in Maine and throughout the species' range and should be taken into account for future management decisions.

Maine↗
USGS2001

Microsatellite DNA variation Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) and cross-species amplification the Acipenseridae

O verharvest and habitat alteration have led to a collapse of most commercial Atlantic sturgeon( Acipenser oxyrinchus oxyrinchus )fisheries while pushing the species to rarity or extirpation in most of its historical range. A biologically sound conservation program for this species requires knowledge of its genetic diversity and of the evolutionary relationships among geographic populations. To address these research needs, six microsatellite loci were isolated from A. o. oxyrinchus . Pedigree analysis suggested that all are inherited in a codominant Mendelian pattern. The six loci were tested in ten additional sturgeon species from three genera and three apparent ploidy levels (4n, 8n, 16n). Approximately 70% of successful locus-species amplifications were polymorphic. Polysomy was observed most often in 8n and 16n species. Genetic diversity and population structure of A. o. oxyrinchus were assayed using three polymorphic Aox markers and four markers developed from lake sturgeon ( A. fulvescens ). A. o. oxyrinchus were sampled from the Altamaha River, Georgia, USA north to the St. Lawrence River, Quebec, Canada. Gulf sturgeon, A. o. desotoi , were sampled from the Suwannee River, Florida, USA, to assess differentiation between the subspecies. Seventy-seven alleles were observed to segregate into unique multilocus genotypes for each of the 392 individuals assayed. Mean diversity was greatest in the Chesapeake Bay (9.7 alleles per locus) and Delaware River (7.4 alleles per locus) collections, and lowest in the St. Lawrence River (4.6 alleles per locus). Mean heterozygosity across seven loci ranged from 44.3% (St. Lawrence River) to 62.6% (Altamaha River). Significant allelic heterogeneity was observed in 82% of pairwise comparisons as well as a global test (p < 0.0001) for A. o. oxyrinchus collections. Genetic distance suggests the presence of at least six subpopulations in A. o. oxyrinchus : St. Lawrence River, St. John River, Hudson River, Delaware River, Albemarle Sound, and Altamaha River. Genetic and geographic distances were positively correlated (r = 0.57, p < 0.03) among A. o. oxyrinchus , suggesting isolation by distance and philopatry. Hierarchical gene diversity analysis indicated significant genetic population structure at every level. Maximum likelihood assignment tests correctly assigned individual fish to collection with a high rate of success (mean = 87.5%); this and other lines of evidence indicated that the Chesapeake Bay collection represents a mixed population of sub-adult sturgeon from northern and southern Atlantic coast populations. Population structure was correlated with that suggested by earlier mitochondrial (mt) DNA analyses. Significant diversity was observed between two Canadian populations from which only a single mt DNA haplotype has been reported.

Conservation Genetics↗
USGS2000

Mitochondrial DNA diversity North American and European Atlantic salmon with emphasis on the downeast rivers of Maine

The displacement loop and NADH-1 dehydrogenase regions of mitochondrial DNA (mtDNA) were amplified by the polymerase chain reaction in 954 Atlantic salmon and digested with 40 restriction endonucleases. Variation was detected with 10 enzymes, resulting in 21 composite haplotypes which were strongly patterned geographically with a major discontinuity observed between most North American (NA) and European salmon. Significant heterogeneity of haplotype frequencies was found within and among all classification levels (continent, country, and river). Haplotype frequencies were significantly different across continents, within European samples, within NA samples, within Canadian samples, within wild Maine samples, within captive Maine strains, and between captive and wild Maine strains. Nine haplotypes occurred only in NA, seven in Maine, three only in Maine, and 11 occurred only in Europe. Some Maine rivers had only a single haplotype, suggesting that effective population sizes may be low. The second most frequent European haplotype occurred in tributaries to one Newfoundland river. Gene trees based on parsimony and genetic distance suggest that the haplotypes are monophyletic within each continent, and that the haplotype found on both continents is intermediate between those of Europe and NA, suggesting common ancestry of all haplotypes.

Maine↗
USGS1999

Targeted stock identification using multilocus genotype 'familyprinting'

We present an approach to stock identification of small, targeted populations that uses multilocus microsatellite genotypes of individual mating adults to uniquely identify first- and second-generation offspring in a mixture. We call the approach ‘familyprinting’; unlike DNA fingerprinting where tissue samples of individuals are matched, offspring from various families are assigned to pairs of parents or sets of four grandparents with known genotypes. The basic unit of identification is the family, but families can be nested within a variety of stock units ranging from naturally reproducing groups of fish in a small tributary or pond from which mating adults can be sampled to large or small collections of families produced in hatcheries and stocked in specific locations. We show that, with as few as seven alleles per locus using four loci without error, first-generation offspring can be uniquely assigned to the correct family. For second-generation applications in a hatchery more alleles per locus (10) and loci (10) are required for correct assignment of all offspring to the correct set of grandparents. Using microsatellite DNA variation from an Atlantic salmon ( Salmo solar ) restoration river (Connecticut River, USA), we also show that this population contains sufficient genetic diversity in sea-run returns for 100% correct first-generation assignment and 97% correct second-generation assignment using 14 loci. We are currently using first- and second-generation familyprinting in this population with the ultimate goal of identifying stocking tributary. In addition to within-river familyprinting, there also appears to be sufficient genetic diversity within and between Atlantic salmon populations for identification of ‘familyprinted’ fish in a mixture of multiple populations. We also suggest that second-generation familyprinting with multiple populations may also provide a tool for examining stock structure. Familyprinting with microsatellite DNA markers is a viable method for identification of offspring of randomly mating adults from small, targeted stocks and should provide a useful addition to current mixed stock analyses with genetic markers.

Fisheries Research↗
USGS1999

Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): Conservation implications of range discontinuity

A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona, as represented by the four species surveyed in this study, may not be monophyletic.

Conference Paper↗