Chromosome numbers and sexual compatibility in North America of Rorippa sylvestris (Cruciferae)

1984 ◽  
Vol 62 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Gerald A. Mulligan ◽  
Derek B. Munro
Keyword(s):  
North America ◽  
North American ◽  
Chromosome Numbers ◽  
Interspecific Hybrid ◽  
Field Observations ◽  
Sexual Compatibility ◽  
Intraspecific Crossing

Tetraploid (2n = 32), pentaploid (2n = 40), and hexaploid (2n = 48) plants of Rorippa sylvestris (L.) Besser (Cruciferae) and a natural pentaploid (2n = 40) interspecific hybrid, R. sylvestris × R. palustris (L.) Besser, are recorded for North America. These counts are compared with published information on European plants. Tetraploids are most common in Europe (68 vs. 20%), whereas hexaploids are most common in North America (65 vs. 29%). Although self-incompatible R. sylvestris rarely sets seed in nature, indicating that plants within most sites are genetically the same clone, intraspecific crossing data, chromosome information, and field observations indicate that North American R. sylvestris results from the vegetative introduction of many different genotypes.

Circaea × intermedia in eastern North America with particular reference to Ontario

1977 ◽  
Vol 55 (23) ◽  
pp. 2919-2935 ◽  
Author(s):  
Erich Haber
Keyword(s):  
North America ◽  
North American ◽  
Chromosome Numbers ◽  
Interspecific Hybrid ◽  
Somatic Chromosome ◽  
Parental Species ◽  
Eastern North America ◽  
Chromosome Counts ◽  
Morphological Differences ◽  
Somatic Chromosome Numbers

Circaea × intermedia Ehrh. in North America is an interspecific hybrid between C. alpina L. and C. lutetiana L. subsp. canadensis Aschers. & Magnus. In spite of the morphological differences that exist between the European and North American subspecies of C. lutetiana, hybrids from both continents are morphologically identical. Documentation of the intermediacy of the hybrid taxon is presented based on the evaluation of the means of 22 characters of specimens from an Ontario locality at which all three taxa are found.Diploid chromosome counts of 2n = 22 are reported for Ontario populations of the hybrid and parental species. The presence of irregular, somatic chromosome numbers are also reported for all three taxa.Distribution maps for all three taxa in eastern North America are included. In the case of C. lutetiana subsp. canadensis, the northern range is sharply delimited by the Precambrian–Paleozoic bedrock boundary.A table of character comparisons and a key to the three taxa summarizes the salient characteristics of the hybrid and the parental species in eastern North America.

Speciation and hybridisation in North American quillworts

1985 ◽  
Vol 86 ◽  
pp. 259-263 ◽  
Author(s):  
W. Carl Taylor ◽  
Neil T. Luebke ◽  
Mary B. Smith
Keyword(s):  
New Species ◽  
North America ◽  
North American ◽  
Chromosome Numbers ◽  
Distribution Patterns ◽  
Spore Formation ◽  
Enzyme Electrophoresis ◽  
Northeastern North America ◽  
Natural Hybrids ◽  
Natural Hybridisation

SynopsisSpecies of Isoetes in northeastern North America may have evolved through hybridisation and allopolyploidy. Evidence for natural hybridisation was obtained from overlapping distribution patterns, abortive and polymorphic spore formation, chromosome numbers ranging from diploid to decaploid, and additive enzyme electrophoresis profiles. The ease with which hybrids form in culture supports the hypothesis that natural hybrids occur and that hybridisation could be involved in the evolution of new species.

Chromosome numbers from pollen in some North American Impatiens (Balsaminaceae)

1974 ◽  
Vol 52 (12) ◽  
pp. 2637-2639 ◽  
Author(s):  
C. C. Chinnappa ◽  
L. S. Gill
Keyword(s):  
North America ◽  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Herbarium Specimens ◽  
Chromosome Counts ◽  
Present Survey ◽  
The One ◽  
Basic Numbers

Chromosome counts for eight species of Impatiens from North American populations have been determined from herbarium specimens. The chromosome number n = 10 for I. ecalcarata Blank, is a new report. It is apparent from the present survey that there are at least three basic numbers (n = 7, 10, and 13) represented in North America as opposed to the one (n = 10) suggested by the earlier workers.

TAXONOMY OF PLANTAGO L. IN NORTH AMERICA: SECTIONS HOLOPSYLLIUM PILGER, PALAEOPSYLLIUM PILGER, AND LAMPROSANTHA DECNE.

1967 ◽  
Vol 45 (5) ◽  
pp. 565-577 ◽  
Author(s):  
I. J. Bassett
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
North American ◽  
Chromosome Numbers ◽  
Native North American ◽  
Considerable Confusion ◽  
The One

The taxonomy, chromosome numbers, distribution, and notes on phytogeography of the one introduced and the six native North American Plantago species in sections Holopsyllium Pilger, Palaeopsyllium Pilger, and Lamprosantha Decne. are presented. Although there has been considerable confusion among the species Plantago eriopoda Torr., P. tweedyi Gray, and P. canescens Adams, this investigation demonstrates that they can be readily separated and that each has a distinctive geographical distribution. Plantago macrocarpa Cham. & Schlecht., P. cordata Lam., P. eriopoda Torr., P. tweedyi Gray, P. sparsiflora Michx., and P. media L. were found to have 24 somatic chromosomes and P. canescens Adams, 12.

A COMPARATIVE STUDY OF THE NORTH AMERICAN SPECIES IN THE CADDISFLY GENUS MYSTACIDES (TRICHOPTERA: LEPTOCERIDAE)

1964 ◽  
Vol 42 (6) ◽  
pp. 1105-1126 ◽  
Author(s):  
T. Yamamoto ◽  
G. B. Wiggins
Keyword(s):  
North America ◽  
Comparative Study ◽  
North American ◽  
Field Observations ◽  
Systematic Data ◽  
Larval Stages ◽  
The Past ◽  
The North ◽  
New Material ◽  
Eurasian Species

Three species of the leptocerid caddisfly genus Mystacides are represented in North America: M. sepulchralis (Walk.), M. alafimbriata H.-G., and M. longicornis (L.). Study of a considerable amount of new material of these species has shown, particularly in the larval and pupal stages, that certain of the characters distinguishing the species, and even the genus itself, have been misinterpreted in the past. Variation in the larval stages has also made identification of the species difficult with existing keys.This comparative study of the larvae, pupae, and adults of the three species has been undertaken to overcome these deficiencies, and to bring together the systematic data now available on these widespread caddisflies. Keys to the species are provided for larvae, pupae, and both adult sexes, and the diagnostic characters illustrated. Available records have been brought together, and maps of the known distribution of each species prepared. Field observations on behavior are noted. The phylogenetic relationships of North American and Eurasian species are discussed.

Synopses of North-American Invertebrates. X. The Oxyrhynchous and Oxystomatous Crabs of North America

1900 ◽  
Vol 34 (402) ◽  
pp. 503-520 ◽  
Author(s):  
Mary J. Rathbun
Keyword(s):  
North America ◽  
North American

Nucleotide polymorphisms in three genes support host and geographic speciation in tree pathogens belonging toGremmeniellaspp.

2002 ◽  
Vol 80 (11) ◽  
pp. 1151-1159 ◽  
Author(s):  
M Dusabenyagasani ◽  
G Laflamme ◽  
R C Hamelin
Keyword(s):  
North America ◽  
Dna Sequences ◽  
North American ◽  
Abies Balsamea ◽  
Host Specialization ◽  
Rrna Genes ◽  
Nucleotide Polymorphisms ◽  
Group I ◽  
Geographic Separation ◽  
Pinus Spp

We detected nucleotide polymorphisms within the genus Gremmeniella in DNA sequences of β-tubulin, glyceraldehyde phosphate dehydrogenase, and mitochondrial small subunit rRNA (mtSSU rRNA) genes. A group-I intron was present in strains originating from fir (Abies spp.) in the mtSSU rRNA locus. This intron in the mtSSU rRNA locus of strains isolated from Abies sachalinensis (Fridr. Schmidt) M.T. Mast in Asia was also found in strains isolated from Abies balsamea (L.) Mill. in North America. Phylogenetic analyses yielded trees that grouped strains by host of origin with strong branch support. Asian strains of Gremmeniella abietina (Lagerberg) Morelet var. abietina isolated from fir (A. sachalinensis) were more closely related to G. abietina var. balsamea from North America, which is found on spruce (Picea spp.) and balsam fir, and European and North American races of G. abietina var. abietina from pines (Pinus spp.) were distantly related. Likewise, North American isolates of Gremmeniella laricina (Ettinger) O. Petrini, L.E. Petrini, G. Laflamme, & G.B. Ouellette, a pathogen of larch, was more closely related to G. laricina from Europe than to G. abietina var. abietina from North America. These data suggest that host specialization might have been the leading evolutionary force shaping Gremmeniella spp., with geographic separation acting as a secondary factor.Key words: Gremmeniella, geographic separation, host specialization, mitochondrial rRNA, nuclear genes.

scholarly journals Progress in Diagnosing Primary Ciliary Dyskinesia: The North American Perspective

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1278
Author(s):  
Michael Glenn O’Connor ◽  
Amjad Horani ◽  
Adam J. Shapiro
Keyword(s):  
Genetic Testing ◽  
North America ◽  
North American ◽  
Primary Ciliary Dyskinesia ◽  
Clinical Phenotype ◽  
The United States ◽  
Diagnostic Process ◽  
The North ◽  
Diagnostic Guideline ◽  
Ciliary Dyskinesia

Primary Ciliary Dyskinesia (PCD) is a rare, under-recognized disease that affects respiratory ciliary function, resulting in chronic oto-sino-pulmonary disease. The PCD clinical phenotype overlaps with other common respiratory conditions and no single diagnostic test detects all forms of PCD. In 2018, PCD experts collaborated with the American Thoracic Society (ATS) to create a clinical diagnostic guideline for patients across North America, specifically considering the local resources and limitations for PCD diagnosis in the United States and Canada. Nasal nitric oxide (nNO) testing is recommended for first-line testing in patients ≥5 years old with a compatible clinical phenotype; however, all low nNO values require confirmation with genetic testing or ciliary electron micrograph (EM) analysis. Furthermore, these guidelines recognize that not all North American patients have access to nNO testing and isolated genetic testing is appropriate in cases with strong clinical PCD phenotypes. For unresolved diagnostic cases, referral to a PCD Foundation accredited center is recommended. The purpose of this narrative review is to provide insight on the North American PCD diagnostic process, to enhance the understanding of and adherence to current guidelines, and to promote collaboration with diagnostic pathways used outside of North America.

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