A cytological study ofCrepis fuliginosa, C. Neglecta, and theirF 1 hybrid, and its bearing on the mechanism of phylogenetic reduction in chromosome number

1943 ◽  
Vol 45 (1) ◽  
pp. 67-111 ◽  
Author(s):  
H. A. Tobgy
Keyword(s):  
Chromosome Number ◽  
Cytological Study

The biosystematics of the genus Lotus (Leguminosae) in Canada. II. Numerical chemotaxonomy

1968 ◽  
Vol 46 (5) ◽  
pp. 585-589 ◽  
Author(s):  
William F. Grant ◽  
Ilse I. Zandstra
Keyword(s):  
Chromosome Number ◽  
Thin Layer ◽  
Native Species ◽  
Cytological Study ◽  
Diploid Species ◽  
Basic Chromosome Number ◽  
Chromatographic Study ◽  
Chemical Identification ◽  
Basic Chromosome ◽  
Fluorescent Compounds

A thin-layer chromatographic study of fluorescent compounds present in native (L. denticulatus, L. formosissimus, L. micranthus, L. pinnatus, L. purshianus) and introduced (L. corniculatus, L. krylovii, L.pedunculatus, L. tenuis) Canadian species of Lotus has been carried out and relationships of the species have been determined on the basis of the coefficients of association of these compounds. Chemical identification of the compounds was not attempted, but test reagents indicated a number to be phenolics. The analysis supported the general taxonomic relationships of the species based on a morphological and cytological study. Of the native species, L. pinnatus and L. formosissimus were the most closely related, with a coefficient of association of 83.33. Lotus denticulatus, the only native species with a chromosome number of n = 6, in general showed lower coefficients of association with the n = 7 species. Of the introduced species, all of which belong to the L. corniculatus group with a basic chromosome number of 6, L. krylovii and L. tenuis had the highest coefficient of association, 75.86. Based on their coefficients of association, both of these diploid species were more closely related to the tetraploid L. corniculatus than to the diploid L. pedunculatus.

A CYTOLOGICAL STUDY OF ASCOCYBE

1961 ◽  
Vol 39 (7) ◽  
pp. 1605-1607 ◽  
Author(s):  
Charles M. Wilson
Keyword(s):  
Life Cycle ◽  
Chromosome Number ◽  
Cytological Study ◽  
Nuclear Behavior

The nuclear behavior in the life cycle of Ascocybe grovesii is described. The chromosome number is given as six from counts made of chromosomes in the meiotic divisions in the asci. The ascophores are described as diploid, and as a consequence there is no fusion of nuclei in the asci.

COCCIDIOIDES IMMITIS: CYTOLOGICAL STUDY ON THE FORMATION OF THE ARTHROSPORES

1969 ◽  
Vol 11 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Kyung Joo Kwon-Ciiung
Keyword(s):  
Chromosome Number ◽  
Nuclear Division ◽  
Cytological Study ◽  
Ring Stage ◽  
Coccidioides Immitis ◽  
Active Growth ◽  
Spindle Apparatus ◽  
Relationship Of ◽  
The Relationship

Somatic nuclear division and the manner of arthrospore formation in saprophytic phase of Coccidioides immitis have been studied. Two distinct nuclear cycles, one occurring during the active growth in young hyphae and another occurring in old thin hyphae or during arthrospore formation, were observed. The first cycle consisted of several stages starting from round resting nuclei → ring stage → V stage → and filaments which divide longitudinally. The two daughter nuclear filaments reorganize into round nuclei. The second cycle is more simple than the first. The round resting nuclei become elongated and constricted at the middle, dividing vertically. The chromosome number appears to be 3. The metaphase plares or spindle apparatus were not seen.The fertile hyphae develop septa not basipetally but synchronously. Alternate cells, after being thus delimited, increase in size and in thickness of wall becoming spores while the intervening cells gradually lose cytoplasm. The nuclei remain, without cytoplasm, in the intervening cells until the adjacent spores are completely matured. The spores are released by fragmentation of the walls of the sterile segments. The relationship of C. immitis to the members of Gymnoascaceae has been discussed.

A new chromosome number in Arctostaphylos uva-ursi

1981 ◽  
Vol 59 (2) ◽  
pp. 272-273 ◽  
Author(s):  
Thomas J. Rosatti
Keyword(s):  
New York ◽  
Chromosome Number ◽  
Cytological Study ◽  
Long Island ◽  
Physiological Tolerance

Populations resembling Arctostaphylos uva-ursi (L.) Spreng. var. coactilis Fernald and MacBride growing on Long Island, New York, U.S.A., provided material for cytological study which resulted in the discovery of a new chromosome number for the species, 2n = 78. These plants differ from the most common expression of this variety in having more linear leaves, a condition that may be associated with a physiological tolerance for relatively high levels of salt in the substratum.

A cytological study of species in the Eusimulium aureum group (Diptera: Simuliidae)

1985 ◽  
Vol 63 (9) ◽  
pp. 2043-2061 ◽  
Author(s):  
Karin G. Leonhardt
Keyword(s):  
North America ◽  
Chromosome Number ◽  
Canary Islands ◽  
New World ◽  
Cytological Study ◽  
Northern Europe ◽  
Old World ◽  
Chromosomal Polymorphisms

Earlier studies by R. W. Dunbar of the monophyletic (n = 2) Eusimulium aureum group were extended. Additional samples of his forms "A" and "B" (temperate North America), "C" and "D" (northern North America), "E" and "F" (Britain, northern Europe, Leningrad), and "G" (California to Guatemala) were analyzed. Two of Dunbar's forms, "I" (Gibraltar, Britain) and "J" (Mediterranean, Madeira, Azores, Leningrad), have been redefined. "K" (Gibraltar) and "L" and "M" (Canary Islands) are new forms. These are described in terms of fixed inversion differences, sex differential segments, and chromosomal polymorphisms. In a cytophylogeny, the Old World "J" forms the link to the New World "C." A preliminary polytene banding comparison of E. aureum and its putative n = 3 relatives reveals that the Old World forms are ancestral to those of the New World. All palaearctic forms have chiasmate meiosis in males, while all nearctic ones, with the remarkable exception of "G," are male achiasmate. Since male achiasmate meiosis is presumably a prerequisite for the reduction in chromosome number, the male-chiasmate condition of Old World forms is assumed to be due to secondary reversion, a postulate that is supported by the derivative male-chiasmate condition of "G."

scholarly journals TIPE SITOLOGI DUA SPESIES PTERIS DALAM HUBUNGANNYA DENGAN KETINGGIAN TEMPA

2001 ◽  
Vol 7 (1) ◽  
pp. 25-28
Author(s):  
Siti Zubaidah
Keyword(s):  
Chromosome Number ◽  
Ploidy Level ◽  
Cytological Study ◽  
Cold Weather ◽  
Different Temperatures

A cytological study of the two species of Pteris (Pteris biaurita and Pteris tripartita) growing around Malang was carried out. A hypothesis stated that ploidy was enchanched by cold weather. Those study want to find out the correlation between the altitude (with different temperatures) and ploidy of the two species. Cytological type and ploidy examined by chromosome number counting, using standart squash method. The result of this research showed that Pteris biaurita and Pteris tripartite have two cytotypes, 2n= 58 (2x or diploid) and 2n= 116 (4x or tetraploid). There was no correlation between the ploidy level of Pteris biaurita and the altitude, but the ploidy level of Pteris tripartite apt to be raise in higher altitude.

scholarly journals The Chromosomes and Systematic Position of the Marsupial Mole, Notoryctes typhlops

1974 ◽  
Vol 27 (5) ◽  
pp. 529 ◽  
Author(s):  
JH Calaby ◽  
LK Corbett ◽  
GB Sharman ◽  
PG Johnston
Keyword(s):  
Chromosome Number ◽  
Cytological Study ◽  
Systematic Position ◽  
Diploid Chromosome Number ◽  
Heterogametic Sex

A cytological study showed that the diploid chromosome number in N. typhlops is 2n = 20. All autosomes are submetacentric and three pairs are somewhat larger than the remainder. The male is the heterogametic sex, and the unpaired chromosomes are a submetacentric one (X) about the same size as the smaller autosomes, and a small acrocentric one (Y).

scholarly journals CHARACTERIZATION OF CHROMOSOME OF STRIPPED KEELBACK Xenochrophis vittattus (Linnaeus, 1758) FROM PIYUNGAN, BANTUL, DAERAH ISTIMEWA YOGYAKARTA

2015 ◽  
Vol 2 (1) ◽  
pp. 278
Author(s):  
Berry Fakhry Hanifa ◽  
Niken Satuti Nurhandayani
Keyword(s):  
Chromosome Number ◽  
Cytological Study ◽  
Natural Habitat ◽  
Blood Cultures ◽  
Habitat Types ◽  
Tropical Country ◽  
Genetic Studies ◽  
Submetacentric Chromosome ◽  
Karyotype Formula

<p>Indonesia is a tropical country which has varies of habitat types that are dispersed into thousands islands. The diversity and its tropical climate, makes Indonesia as a suitable place as a natural habitat for herpetofauna, especially Sub Order Serpentes. Xenochrophis vittattus (Linnaeus, 1578), called stripped keelback snakes, is a semi-aquatic snakes spread in Indonesia, especially in Java, Sumatra, Bangka, and Manado, and commonly used as pet. Since there are few reports on genetic studies, especially in the field of karyology, this study aims to characterize the chromosomes of stripped keelback from Piyungan population, Bantul, Yogyakarta. This study used a brief splash of blood cultures method. This has been known as the first stripped keelback cytological study in Indonesia. The results showed that striped keelback has a diploid chromosome (2n) = 34, consists of metacentric chromosome (number 1, 2, 3, 4, 19, 20, 21, 22, 23, 24, 25, and 26); submetacentric chromosome (number 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18). Whereas the chromosome number 27, 28, 29, 30, 31, 32, 33, and 34 were micro chromosomes. Striped keelback karyotype formula was 2n = 2x = 34 = 12 m 14 sm 8 micro chromosomes. The longest chromosome of stripped keelback was 2.9335 ± 0.1772 um, whereas the shortest one was 0.5088 ± 0.013 um, and the R value was 5.9106 ± 1.1265.</p><p><br /><strong>Keywords</strong>: Xenochrophis vittattus, Stripped keelback, chromosome characterization, karyotype</p>

A CYTOLOGICAL STUDY OF THREE SPECIES AND A HYBRID TAXON OF LYCOPODIUM (SECTION COMPLANATA) IN ONTARIO

1981 ◽  
Vol 23 (3) ◽  
pp. 497-504 ◽  
Author(s):  
R. E. Hersey ◽  
D. M. Britton
Keyword(s):  
Chromosome Number ◽  
Genome Analysis ◽  
Cytological Study ◽  
Cytological Evidence ◽  
Regular Meiosis

A cytological study was carried out on three species and a hybrid taxon of Section Complanata Vict, of the genus Lycopodium L. in Ontario, Canada. The taxa studied were L. complanatum L., L. flabelliforme (Fern.) Blanchard, L. tristachyum Pursh and L. × habereri House. These taxa were examined cytologically in order to determine chromosome number and to study and compare meiosis in hybrids with meiosis in nonhybrid specimens. The chromosome number for all taxa was found to be n = 23, a number in agreement with the more recent chromosome number reports for these particular lycopods. Meiosis in L. × habereri, was found to be identical to meiosis in L. complanatum, L. flabelliforme and L. tristachyum, i.e. no irregularities were observed in the meiosis of the hybrid. Similar results were also obtained for specimens expressing morphological intermediacy between the taxa, L. complanatum and L. tristachyum and therefore possible hybrids of these two taxa. This result was completely unexpected in light of genome analysis in other pteridophytes. Due to the occurrence of regular meiosis in hybrids, cytological evidence cannot be used as a means of verifying hybridization, at least within Section Complanata of the genus Lycopodium.

Sign in / Sign up

Export Citation Format

Share Document