The origin of Dryopteris campyloptera

1977 ◽  
Vol 55 (10) ◽  
pp. 1419-1428 ◽  
Author(s):  
Mary Gibby
Keyword(s):  
Chromosome Pairing ◽  
North American ◽  
Diploid Species ◽  
Tetraploid Species ◽  
The North ◽  
Independent Origin

In an attempt to establish the origin of the North American tetraploid Dryopteris campyloptera, hybrids have been synthesized and the chromosome pairing at meiosis investigated. It seems probable that it is derived from two diploid species, D. assimilis and D. intermedia. Dryopteris austriaca, a tetraploid species from Europe, is derived from the same diploid species but it may well have had an independent origin.

CYTOTAXONOMIC STUDIES ON NEW WORLD SPECIES OF ANEMONE (SECTION ERIOCEPHALUS) WITH TUBEROUS ROOTSTOCKS

1966 ◽  
Vol 44 (7) ◽  
pp. 899-928 ◽  
Author(s):  
Cecily Joseph ◽  
Margaret Heimburger
Keyword(s):  
North American ◽  
New World ◽  
Diploid Species ◽  
Pollen Grain ◽  
South American ◽  
New Taxon ◽  
South American Species ◽  
The North ◽  
Additional Support ◽  
North And South

The American species of Anemone L. (section Eriocephalus Hook. f. & Thoms.) with tuberous rootstocks were studied by biosystematic methods. Anemone caroliniana Walt., A. heterophylla Nutt. ex Torr. & Gray, A. tuberosa Rydb., and A. edwardsiana Tharp (tentatively) are recognized from North America and A. decapetala Ard., A. triternata Vahl, and A. cicutifolia Johnst. from South America. Karyotypes of the diploid species (2n = 16), A. heterophylla, A. tuberosa, A. decapetala, and A. triternata are described. They resemble the karyotype of A. caroliniana published earlier. Anemone edwardsiana and A. cicutifolia are also presumed diploid from stomatal and pollen grain studies. A new taxon (2n = 32), of undecided status, was obtained from Chile. North American plants included by authors in A. decapetala are here referred to A. heterophylla. The North and South American species appear to form two separate groups, the species of each continent being more closely related among themselves than to those of the other continent. Fewer stomata, larger chromosome size, and higher DNA content are characteristic of the North American species. Additional support for the separation of the two groups derives from limited meiotic studies which indicate a larger number of inversion differences in inter- than in intra-continental hybrids.

Revisiting the evolution of the North American tetraploid treefrog (Hyla versicolor)

Genome ◽  
2020 ◽  
Vol 63 (11) ◽  
pp. 547-560 ◽  
Author(s):  
James P. Bogart ◽  
Patrick Burgess ◽  
Jinzhong Fu
Keyword(s):  
Diploid Species ◽  
Hyla Versicolor ◽  
Hyla Chrysoscelis ◽  
Gene Exchange ◽  
Tetraploid Species ◽  
Sympatric Populations ◽  
Female Progeny ◽  
The North ◽  
Mating Call ◽  
Mitochondrial Cytochrome B

Hyla chrysoscelis and H. versicolor are common treefrogs in eastern North America and are a cryptic diploid–tetraploid species pair. They are morphologically identical but H. versicolor is a tetraploid. They can be identified acoustically by the male’s advertisement mating call, which has a pulse repetition rate that has twice as many pulses per second in the diploid species, H. chrysoscelis. We used isozymes, microsatellite DNA alleles, and mitochondrial cytochrome b sequences to test the hypothesis that gene exchange occurs between the diploid and tetraploid species in sympatric populations. Each method provided results that are best explained by occasional hybridization of female H. versicolor and male H. chrysoscelis. We propose that H. versicolor first arose from an autotriploid H. chrysoscelis female that produced unreduced triploid eggs. After H. versicolor became established, genes could be passed from H. chrysoscelis to H. versicolor in sympatric populations when these species hybridize. Their F1 female progeny produce unreduced triploid eggs that are fertilized by haploid H. chrysoscelis sperm to reconstitute H. versicolor. Genes can be passed from diploid H. chrysoscelis to tetraploid H. versicolor in sympatric populations.

Allopolyploid speciation of the Mexican tetraploid potato species Solanum stoloniferum and S. hjertingii revealed by genomic in situ hybridization

Genome ◽  
2008 ◽  
Vol 51 (9) ◽  
pp. 714-720 ◽  
Author(s):  
Galina Pendinen ◽  
Tatjana Gavrilenko ◽  
Jiming Jiang ◽  
David M. Spooner
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Pairing ◽  
Diploid Species ◽  
Genomic In Situ Hybridization ◽  
Tetraploid Species ◽  
Genome Donor ◽  
A Genome ◽  
Section Petota ◽  
Gish Analysis

Thirty-six percent of the wild potato ( Solanum L. section Petota Dumort.) species are polyploid, and about half of the polyploids are tetraploid species (2n = 4x = 48). Determination of the type of polyploidy and development of the genome concept for members of section Petota traditionally has been based on the analysis of chromosome pairing in species and their hybrids and, most recently, DNA sequence phylogenetics. Based on these data, the genome designation AABB was proposed for Mexican tetraploid species of series Longipedicellata Buk. We investigated this hypothesis with genomic in situ hybridization (GISH) for both representatives of the series, S. stoloniferum Schltdl. and S. hjertingii Hawkes. GISH analysis supports an AABB genome constitution for these species, with S. verrucosum Schltdl. (or its progenitor) supported as the A genome donor and another North or Central American diploid species (S. cardiophyllum Lindl., S. ehrenbergii (Bitter) Rydb., or S. jamesii Torrey) as the B genome donor. GISH analysis of chromosome pairing of S. stoloniferum also confirms the strict allopolyploid nature of this species. In addition, fluorescence in situ hybridization data suggest that 45S rDNA regions of the two genomes of S. stoloniferum were changed during coevolution of A and B genomes of this allotetraploid species.

CYTOTAXONOMIC STUDIES ON RUMEX SECTION AXILLARES

1958 ◽  
Vol 36 (6) ◽  
pp. 947-996 ◽  
Author(s):  
Nina Marie Sarkar
Keyword(s):  
Pollen Fertility ◽  
Diploid Species ◽  
Taxonomic Revision ◽  
The United States ◽  
Herbarium Specimens ◽  
Tetraploid Species ◽  
Structural Hybridity ◽  
The North ◽  
Essentially Normal ◽  
Very High

The present investigation covers only the North American species of Rumex subgenus Rumex (Lapathum) section Axillares. A review was made of all the previous taxonomical and cytological work done in this group. All the species of the section Axillares were morphologically studied and their natural distribution plotted on maps. The distributional data were derived from about 3000 herbarium specimens gathered from various herbaria in the United States and Canada. Chromosome numbers of 17 taxa of the section Axillares were determined. The three subsections were found to comprise a polyploid series, the monotypic subsection Venosi with 2n = 40, R. verticillatus of the subsection Verticillati with 2n = 60, and all but two of the species studied in the subsection Salicifolii with 2n = 20; the two exceptions were R. mexicanus and R. utahensis, both with 2n = 40. Meiosis was studied in the species of the subsection Salicifolii only. Both the diploid and the tetraploid species showed essentially normal meiotic behavior. Pollen fertility was also very high in all the species. A number of intra- and inter-specific hybridizations were made between the taxa in the subsection Salicifolii, involving both the diploid and the tetraploid species. The resulting diploid (diploid × diploid), triploid (diploid × tetraploid), and tetraploid (tetraploid × tetraploid) F1 hybrids were both morphologically and cytologically studied. Morphologically almost all the diploid and tetraploid hybrids were intermediate between the two parents. The triploid hybrids showed more similarity to the tetraploid species involved in the cross, Meiosis in all the diploid hybrids was essentially normal with 10 bivalents. However, there was a significant decrease in chiasma frequency as compared with the parent species. This was postulated to be due to cryptic structural hybridity. There were three different categories of pollen fertility, ranging from low to very high, which were not correlated with any meiotic irregularities. All the diploid hybrids were fertile and set abundant seeds. Meiosis in the triploid hybrids was very irregular with mostly 10 bivalents and 10 univalents at metaphase I. Anaphases were also irregular, resulting in numerous micronuclei. All the triploid hybrids were sterile and set only a few undeveloped seeds. Meiosis in the tetraploid hybrid studied was also irregular with mostly 9 bivalents and 22 univalents. It was thus postulated that both the tetraploid species are allotetraploids with one genome in common between them and that this genome is essentially the same one shared by the diploid species so far cytologically studied. The tetraploid hybrids were completely sterile and did not set any seed. From the cytogenetic data, the diploid species studied were shown to be very closely interrelated. However, no taxonomic revision was undertaken owing to lack of more complete data involving all the species comprising the group.

1588: The Bicalutamide Early Prostate Cancer Program: Findings of the North American Trial at 7.7 Years' Median Follow-Up

2006 ◽  
Vol 175 (4S) ◽  
pp. 511-512
Author(s):  
David G. McLeod ◽  
Ira Klimberg ◽  
Donald Gleason ◽  
Gerald Chodak ◽  
Thomas Morris ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
North American ◽  
Early Prostate Cancer ◽  
The North ◽  
Cancer Program
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