The Chromosome Numbers and Nuclear Cytology of Some Common British Serpulids

1960 ◽  
Vol s3-101 (56) ◽  
pp. 395-400
Author(s):  
S. DASGUPTA ◽  
A. P. AUSTIN
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Somatic Cells ◽  
Diploid Chromosome Number ◽  
Iron Alum ◽  
Artificial Fertilization ◽  
Nuclear Cytology

The chromosome numbers of Hydroides norvegica, Mercierella enigmatica, and Pomatoceros triqueter were determined from squashes of somatic cells in young embryos obtained by artificial fertilization, and stained with iron-alum/aceto-carmine. All had a diploid count of zn = 26 chromosomes. Mitotic and meiotic divisions in the 5 species of Spirorbis examined, and in Filograna implexa, all revealed a diploid chromosome number of 2n = 20. A diploid chromosome number of 14 is suggested for the ancestral serpulid.

scholarly journals Estudios citogenéticos de dos especies y una variedad del género Nyctocereus (Cactaceae)

2017 ◽  
pp. 75
Author(s):  
Guadalupe Palomino-Hasbach ◽  
Socorro Zuleta-Lechuga ◽  
Leia Scheinvar
Keyword(s):  
Chromosome Number ◽  
Central America ◽  
Chromosome Numbers ◽  
Basic Number ◽  
Diploid Chromosome Number

The genus Nyctocereus (Cactaceae) consists of seven species and two varieties distributed from Mexico to Central America. They are valued as ornamental and for its edible fruits. In this study the chromosome numbers were determined and the karyotypes elaborated for N. castellanossi, N. serpentinus and N. serpentinus var. splendens. The diploid chromosome number for the three taxa was 2n = 22 and the karyotypes were very homogenous. No polyploids were detected. The basic number is x= 11. All the chromosomes in N. castellanosii and N. serpentinus were metacentric, while in N. serpentinus var. splendens two pairs of submetacentric chromosomes were observed. The total chromatin length was different for the three species, finding the lowest value in N. serpentinus var. splendens.

scholarly journals Peculiarities of chromosomal variability in cultured tissues of Deschampsia antarctica Desv. plants with different chromosome numbers

2016 ◽  
Vol 14 (1) ◽  
pp. 36-43 ◽  
Author(s):  
V. A. Kunakh ◽  
D. O. Navrotska ◽  
M. O. Twardovska ◽  
I. O. Andreev
Keyword(s):  
Tissue Culture ◽  
Chromosome Number ◽  
Chromosome Numbers ◽  
Diploid Chromosome Number ◽  
Deschampsia Antarctica ◽  
Donor Plant ◽  
Modal Class ◽  
Chromosomal Variability ◽  
Diploid Cells

Aim. To clarify the details of chromosome variation in calli derived from D. antarctica plants in the initial passages of the culture in vitro. Methods. Induction of callus from root explants of plants, which were grown from seeds, and consequent subcultivation of tissue culture. Cytogenetic analysis of squashed slides stained by acetic-orcein and counting the number of chromosomes in mitotic metaphase plates. Results. There were analyzed the cultured tissues derived from D. antarctica plants with different chromosome numbers: diploid plants (2n=26), mixoploid plant with B-chromosomes (2n=26+1-3B), and mixoploid plant with near-triploid modal class (2n=36, 38). Analysis of callus tissues of all plants at 2-4 passages revealed mixoploidy, presence of polyploid and aneuploid cells. The modal class in all studied calli was composed of diploid and aneuploid cells with near-diploid chromosome number. The cytogenetic structure of cell population of cultured tissues was found to vary with characteristics of the karyotype of donor plant. The largest range of variation in the number of chromosomes (from 18 to 63 chromosomes) was found in tissue culture of diploid plant (2n=26) from the Galindez Island, and the highest frequencies of polyploid (47 %) and aneuploid cells were in the culture of mixoploid plant with near-triploid modal class from the Big Yalour Island. Conclusions. In different D. antarctica cultured tissues at the early stages of the culture, the modal class was composed of diploid cells and cells with near-diploid chromosome number irrespective of karyotype of donor plant (diploid, mixoploid poliploid).Key words: Deschampsia antarctica Desv., plant tissue culture, chromosomal variability in vitro, mixoploidy.

scholarly journals Chromosomal analysis of Astyanax fasciatus (PISCES, CHARACIDAE) from the Araguari river, Uberlândia, MG, Brazil

2006 ◽  
Vol 66 (1a) ◽  
pp. 161-165 ◽  
Author(s):  
A. R. Torres-Mariano ◽  
S. Morelli
Keyword(s):  
Chromosome Number ◽  
Silver Nitrate ◽  
Chromosome Numbers ◽  
Chromosomal Analysis ◽  
Diploid Chromosome Number ◽  
Nucleolar Organizing Regions ◽  
Astyanax Fasciatus ◽  
The Family ◽  
Silver Nitrate Staining ◽  
Parana Basin

The genus Astyanax is one of the most numerous of the family Characidae, comprising a large number of similar-shaped species, but displaying innumerable karyotypic variations in its chromosome number and/or structure. The literature describes A. fasciatus populations with diploid chromosome numbers varying from 2n = 45 to 2n = 48. In this study, A. fasciatus specimens captured in the Araguari River (Alto Paraná basin) were cytogenetically characterized, revealing a diploid chromosome number of 2n = 46. The nucleolar organizing regions (NORs), detected with silver nitrate staining, showed a multiple system with two pairs of marked chromosomes. These findings are congruent with those of other studies involving populations of the same species.

CYTOTAXONOMY OF THREE SPECIES OF CENTAUREA ADVENTIVE IN CANADA

1954 ◽  
Vol 32 (1) ◽  
pp. 182-186 ◽  
Author(s):  
R. J. Moore ◽  
C. Frankton
Keyword(s):  
Chromosome Number ◽  
Introduced Species ◽  
Chromosome Numbers ◽  
Diploid Chromosome Number ◽  
Chromosome Counts ◽  
Normal Pollen ◽  
Taxonomic Problem ◽  
First Time

The chromosome numbers of three introduced species of Centaurea are here reported: C. diffusa Lam., 2n = 18; C. maculosa, Lam., 2n = 36; C. repens L., 2n = 26. The chromosome counts of C. diffusa and of C. maculosa, which are here reported for the first time, help to clarify a taxonomic problem. A pappus is usually lacking on the achenes of C. diffusa but is present on those of C. maculosa. As a result, plants of C. diffusa with a short pappus have been considered to be possible hybrids between these species. Three such plants here studied had the diploid chromosome number 18, rather than the triploid number to be expected in such a hybrid. Examination of pollen of suspected hybrid specimens shows that the percentage of normal pollen is high. This fact also supports the belief that plants of C. diffusa with a short pappus on the achene are not hybrids with C. maculosa.

A new diploid chromosome number for tomato (Lycopersicon esculentum)?

1984 ◽  
Vol 26 (5) ◽  
pp. 636-639 ◽  
Author(s):  
P. Banks
Keyword(s):  
Chromosome Number ◽  
Lycopersicon Esculentum ◽  
Chromosome Numbers ◽  
Centric Fusion ◽  
Diploid Chromosome Number ◽  
Mitotic Chromosomes ◽  
Tomato Chromosome ◽  
Hybrid Variety ◽  
Numerical Variation ◽  
Morphological Differences

The recognized chromosome number of tomato has been 2n = 24. In this paper the chromosome number 2n = 26 is reported in 18 varieties of tomato. One commercial hybrid variety, revealed 25 mitotic chromosomes. This variety, as well as the varieties with 26 chromosomes, appeared to be fully fertile. Different chromosome numbers did not appear to be associated with any morphological differences between the varieties examined. Preliminary meiotic examination of the variety 'Flora-Dade' (2n = 26 mitotic chromosomes) sometimes revealed 12 associations of chromosomes and sometimes 13 associations. Meiotic examination of the variety 'Sunny' (2n = 25 mitotic chromosomes) revealed what appeared to be 12 bivalents. Centric fission may account for the numerical variation of the diploid chromosome number of tomatoes.Key words: Lycopersicon, tomato, chromosome number, centric fusion.

The Chromosomes of 4 Genera of Possums From the Family Petauridae (Marsupialia, Diprotodonta)

1990 ◽  
Vol 38 (1) ◽  
pp. 33 ◽  
Author(s):  
JD Murray ◽  
SC Donnellan ◽  
GM Mckay ◽  
RH Rofe ◽  
PR Baverstock ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Chromosomal Rearrangement ◽  
Diploid Chromosome Number ◽  
The Family ◽  
Relationship Of ◽  
The Relationship ◽  
Petaurus Australis

The standard and C-banded (four species) karyotypes of six species of the family Petauridae (Gymnobelideus leadbeateri, Petaurus australis, P. breviceps, P. norfolcensis, Dactylopsila trivirgata and Dactylonax palpator) are described. The G-banded karyotype of P. norfolcensis is also described. Gymnobelideus and Petaurus have diploid chromosome number of 22. All three species of Petaurus have a similar karyotype, consisting of biarmed autosomes and very small sex chromosomes, which differs from Gymnobelideus by a minimum of one chromosomal rearrangement of each autosome. Dactylopsila and Dactylonax have similar karyotypes with diploid chromosome numbers of 18. The relationship of these two genera to Petaurus is still uncertain but all members of this family differ from Pseudocheiridae in the small size of the sex chromosomes.

The Chromosome Numbers of certain Barnacles in British Waters

1958 ◽  
Vol s3-99 (48) ◽  
pp. 497-504
Author(s):  
A. P. AUSTIN ◽  
D. J. CRISP ◽  
A. M. PATIL
Keyword(s):  
Chromosome Numbers ◽  
Mantle Cavity ◽  
Polar Bodies ◽  
Iron Alum ◽  
Cytological Changes

The chromosome numbers of nine species of sessile barnacles have been determined from squashes of young embryos stained by an iron alum aceto-carmine method. All the species of Balanus examined, and Elminius modestus had a diploid count of 32 chromosomes. Chthamalus stellatus and Verruca stroemia had each 30 chromosomes. Meiosis occurs after the egg passes into the mantle cavity, and the cytological changes accompanying the extrusion of the two polar bodies are figured.

scholarly journals New Contribution to the Knowledge on the Chromosome Numbers of Turkish Cerambycidae (Coleoptera)

2021 ◽  
Vol 69 (2) ◽  
pp. 93-99
Author(s):  
Yavuz Koçak ◽  
Elmas Yağmur
Keyword(s):  
Chromosome Number ◽  
Sex Determination ◽  
Chromosome Numbers ◽  
Chromosome Count ◽  
Chromosomal Number ◽  
The Poor ◽  
Karyological Data ◽  
First Time

Information on the karyotypes of Turkish species of Cerambycidae is scanty. Our study contributes to the knowledge of the karyological data (chromosomal number and mechanism of sex determination) of five Turkish longicorn beetles; karyotypes of four taxa, one endemic, are described for the first time and for the remaining one, Purpuricenus budensis (Götz, 1783), the previously published chromosome count is confirmed. The chromosome number of Purpuricenus desfontainii inhumeralis Pic, 1891 and Purpuricenus budensis (Götz, 1783) (Cerambycinae, Trachyderini) was found to be 2n = 28 (13 + Xyp); Clytus rhamni Germar, 1817 and Plagionotus floralis (Pallas, 1773) (Cerambycinae, Clytini) 2n = 20 (9 + Xyp); and the endemic Dorcadion triste phrygicum Peks, 1993 (Lamiinae, Dorcadionini) 2n = 24 (11 + Xyp). In view of the paucity of data available until now, our study is important for both to improve the poor karyological knowledge of Turkish Cerambycidae and to provide an incentive for other researchers.

scholarly journals Karyotype Analysis of Alnus Mill. (Betulaceae) Species Originating From Northeastern Asia

2010 ◽  
Vol 59 (1-6) ◽  
pp. 219-223 ◽  
Author(s):  
Liu Jun ◽  
Ren Bao-Qing ◽  
Luo Peigao ◽  
Ren Zhenglong
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Karyotype Analysis ◽  
Full Potential ◽  
Northeastern Asia ◽  
Ploidy Levels ◽  
Genetic Makeup ◽  
Fossil Records

Abstract Alnus Mill. (alder) is an ecologically valuable tree genus. It is essential to study its genetic makeup in order to use alder trees to their full potential. Five specimens from four Alnus species (A. mandshurica, A. pendula, A. sibirica, and A. sieboldiana), found in northeastern Asia, were subjected to karyotype analysis. The analysis showed that these tree samples could be divided into three categories based on chromosome numbers or ploidy levels: viz., 2n = (4x) = 28, 2n = (8x) = 56 and 2n = (16x) = 112. The differences in chromosome number and karyotype parameters among Alnus species and even within the same species possibly resulted from natural polyploidization. Comparing the chromosome numbers of Alnus species in China with those in Japan showed that there appear to be only two categories in China, whereas there are up to five categories in Japan. The earliest fossil records of Alnus pollen were also discovered in Japan. We conclude that the center origin of Alnus spp. is Japan rather than China.

scholarly journals One more Microtus species with asynaptic sex chromosomes

2018 ◽  
Vol 70 (3) ◽  
pp. 443-447
Author(s):  
Jelena Blagojevic ◽  
Marija Rajicic ◽  
Vladimir Jovanovic ◽  
Tanja Adnadjevic ◽  
Ivana Budinski ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Diploid Chromosome Number ◽  
First Finding ◽  
Chromosomal Polymorphisms ◽  
Southeastern Serbia

Arvicoline voles are known as a karyotypically extremely polymorphic group in which the genus Microtus leads with the highest rate of karyotype change. A member of this genus, the European pine vole Microtus subterraneus (de Selys-Longchamps, 1836), is widely distributed in Europe and parts of Asia. There are two cytotypes differing in diploid chromosome number, 2n=54 and 52, each showing different chromosomal polymorphisms. At two localities in southeastern Serbia, Mt. Jastrebac and Vlasina, we found the 2n=52 cytotype. Meiotic preparations from males revealed the presence of asynaptic sex chromosomes. Although asynaptic sex chromosomes are frequent in Microtus, this is the first finding for M. subterraneus. From summarized data it appears that two-thirds of the studied species, mainly from Microtus and Terricola subgenera, possess asynaptic sex chromosomes.

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