The chromosome numbers of five North American and European leech species

1987 ◽  
Vol 65 (3) ◽  
pp. 681-684 ◽  
Author(s):  
Ronald W. Davies ◽  
R. N. Singhal
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Chromosome Evolution ◽  
Chromosome Counts ◽  
Prophase I ◽  
Metaphase I

Chromosome counts were obtained for four glossiphoniid species belonging to three genera (Glossiphonia, Theromyzon, Placobdella) and for one erpobdellid species (Dina lineata) of freshwater leeches. Theromyzon rude, which has a Palaearctic distribution, had seven bivalents at prophase I and metaphase I, while the Holarctic T. tessulatum had eight bivalents, giving diploid chromosome numbers of 14 and 16, respectively. Placobdella papillifera from Alberta had a chromosome number of 2n = 24 and Glossiphonia complanata from Alberta and England had chromosome counts of 2n = 28. At prophase I and metaphase I nine bivalents occurred in the majority of the nuclei of Dina lineata. These findings are discussed in relation to the chromosome evolution and phylogenetic schemes proposed by previous authors.

Chromosome numbers of 15 North American bumble bee species (Hymenoptera, Apidae, Bombini)

1983 ◽  
Vol 25 (1) ◽  
pp. 26-29
Author(s):  
Robin E. Owen
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Morphological Divergence ◽  
Chromosome Counts ◽  
Monophyletic Origin ◽  
The Social

Chromosome counts were obtained for 14 Bombus Latr. species (the social bumble bees) belonging to four subgenera and for one Psithyrus Lep. species (the social parasitic bumble bees). In Bombus the haploid numbers were consistent within each subgenus and there was variation between subgenera; the subgenera Bombus s.s. and Pyrobombus have n = 18, while Separatobombus and Cullumanobombus have n = 19. Thus considerable morphological divergence between subgenera is often, but not always, paralleled by divergence in chromosome number. Psithyrus ashtoni has n = 25, higher than all Bombus species yet examined. This provides support for the monophyletic origin of Psithyrus, but the high n is not expected if eusociality selects for increase in chromosome number.

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.

Chromosome numbers and the taxonomy of North American Agalinis (Scrophulariaceae)

1984 ◽  
Vol 62 (3) ◽  
pp. 454-456 ◽  
Author(s):  
Judith M. Canne
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Base Number ◽  
Chromosome Counts ◽  
Base Chromosome Number ◽  
First Time

Chromosome counts are provided for 25 populations representing 18 species of Agalinis Raf. Chromosome numbers are reported for the first time for A. pinetorum, A. laxa, A. acuta, A. gattingeri, and A. skinneriana. The base chromosome number for section Linifoliae, section Heterophyllae, section Purpureae subsections Purpureae and Setaceae, and section Tenuifoliae is established at x = 14. Section Erectae and section Purpureae subsection Pedunculares have a base number of x = 13.

scholarly journals Animal chromosome counts reveal similar range of chromosome numbers but with less polyploidy in animals compared to flowering plants

2020 ◽  
Author(s):  
Cristian Román-Palacios ◽  
Cesar A. Medina ◽  
Shing H. Zhan ◽  
Michael S. Barker
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Chromosome Evolution ◽  
Chromosome Count ◽  
Flowering Plants ◽  
Similar Distribution ◽  
Chromosome Counts ◽  
Remarkable Similarity ◽  
Similar Range

AbstractUnderstanding the mechanisms that underlie chromosome evolution may provide insights into the processes underpinning the origin, persistence, and evolutionary tempo of lineages. Here we present the first database of chromosome counts for animals (the Animal Chromosome Count database, ACC) summarizing chromosome numbers for ∼18,000 species. We found remarkable similarity in the distribution of chromosome counts between animals and flowering plants. At larger timescales, selection towards a specific range might explain the similar distribution of chromosome counts between these two groups. Nevertheless, changes in chromosome number are still potential drivers of divergence among species at shorter timescales. We also found that while animals and plants exhibit similar frequencies of speciation-related changes in chromosome number, plant speciation is more often related to changes in ploidy. Based on the ACC, our analyses suggest that changes in chromosome number alone could help explain patterns of diversity within animal clades.

scholarly journals Unprecedented reorganization of holocentric chromosomes provides insights into the enigma of lepidopteran chromosome evolution

2019 ◽  
Vol 5 (6) ◽  
pp. eaau3648 ◽  
Author(s):  
Jason Hill ◽  
Pasi Rastas ◽  
Emily A. Hornett ◽  
Ramprasad Neethiraj ◽  
Nathan Clark ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Evolution ◽  
Chromosome Structure ◽  
Holocentric Chromosomes ◽  
Chromosome Counts ◽  
Pieris Napi ◽  
Haploid Chromosome Number ◽  
Genome Wide ◽  
The Face ◽  
Chromosome Level

Chromosome evolution presents an enigma in the mega-diverse Lepidoptera. Most species exhibit constrained chromosome evolution with nearly identical haploid chromosome counts and chromosome-level gene collinearity among species more than 140 million years divergent. However, a few species possess radically inflated chromosomal counts due to extensive fission and fusion events. To address this enigma of constraint in the face of an exceptional ability to change, we investigated an unprecedented reorganization of the standard lepidopteran chromosome structure in the green-veined white butterfly (Pieris napi). We find that gene content in P. napi has been extensively rearranged in large collinear blocks, which until now have been masked by a haploid chromosome number close to the lepidopteran average. We observe that ancient chromosome ends have been maintained and collinear blocks are enriched for functionally related genes suggesting both a mechanism and a possible role for selection in determining the boundaries of these genome-wide rearrangements.

scholarly journals Chromosome Number and Meiotic Behavior of Cultivated Chia, Salvia hispanica (Lamiaceae)

HortScience ◽  
1990 ◽  
Vol 25 (12) ◽  
pp. 1646-1647 ◽  
Author(s):  
A. Estilai ◽  
A. Hashemi ◽  
K. Truman
Keyword(s):  
Chromosome Number ◽  
Species Identification ◽  
Southern California ◽  
Herbarium Specimens ◽  
Meiotic Behavior ◽  
Root Tips ◽  
Chromosome Counts ◽  
Salvia Hispanica ◽  
Meiotic Analyses ◽  
Metaphase I

Edible chia seeds, purchased from the local markets in Guatemala, Mexico, and southern California, were used for species identification, chromosome counts, karyotype construction, and meiotic analyses. Plants raised from those seeds had ovate leaves, dense racemose inflorescences, pale-blue flowers, and were identified from herbarium specimens as Salvia hispanica L. Mitotic analyses of root tips from 50 plants showed 2n = 12—the lowest chromosome number in the genus. Chromosomes were small, ranging from 2 to 3.5 pm. One pair of chromosomes was metacentric (with the long arm: short arm ratio, r = 1.5), four pairs were submetacentric (r = 2.6 to 3.6), and one pair was telocentric (r = 12). Meiosis was regular and six bivalents were observed at metaphase I. Ring and rod bivalents averaged 1.53 ± 1.05 and 4.47 ± 1.05, respectively;

CYTOLOGICAL STUDIES IN THE GENUS ERIGERON

1960 ◽  
Vol 38 (3) ◽  
pp. 381-386 ◽  
Author(s):  
F. H. Montgomery ◽  
Shung-Jun Yang
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Large Area ◽  
Chromosome Counts

The literature relating to the chromosome numbers in the genus Erigeron has been reviewed, and all reported numbers are given. The chromosome number for E. breweri var. porphyreticus (Jones) Cronquist, 2n = 18; E. divergens var. cinereus A. Gray, 2n = 27; E. glabellus var. glabellus Cronquist, 2n = 36; E. glabellus var. pubescens (Hook.) Cronquist, 2n = 36; E. hyssopifolius Michx., 2n = 18; E. quercifolia Lam., 2n = 36; E. simplex Greene, 2n = 27; E. strigosus var. beyrichii (Fisch. & Mey.) A. Gray, 2n = 27; and E. vernus T. & G., 2n = 18 are new determinations. Different numbers from those previously reported have been found for E. pulchellus Michx., 2n = 27, and E. strigosus (Muhl.) Willd., 2n = 36. Chromosome counts over a large area of their distribution have been made for E. annuus (L.) Pers., E. pulchellus Michx., E. philadelphicus L., and E. strigosus (Muhl.) Willd.

scholarly journals Chromosome number and meiotic behavior in several plant taxa from iran

2021 ◽  
Vol 45 (2) ◽  
pp. 333-339
Author(s):  
Seyed Ghaffari ◽  
Abbas Zare ◽  
Fereshteh Corom ◽  
Masoureh Sedaghati
Keyword(s):  
Chromosome Number ◽  
Endemic Species ◽  
Chromosome Numbers ◽  
Mitotic Chromosome ◽  
Vascular Plant ◽  
Meiotic Behavior ◽  
Chromosome Counts ◽  
Plant Families ◽  
First Time ◽  
Accessory Chromosomes

Original meiotic or both meiotic and mitotic chromosome numbers are reported for ten endemic and one non endemic species in nine vascular plant families from Iran. The chromosome numbers of Acantholimon schahrudicum, A. truncatum, Anthochlamys multinervis, Campanula perpusilla, Cousinia calcitrapa var. interrupta, Dorema ammoniacum, Euphorbia gedrosiaca, and Hyocyamus orthocarpus were determined for the first time. The chromosome counts for Astrodaucus persicus and Hedysarum criniferum agree with previous ones. The gametic chromosome numbers for Hedysarum criniferum and Allium stipitatum are reported here for the first time. The occurrence of accessory chromosomes are also reported for Acantholimon schahrudicum and Dorema ammoniacum, being the first records of B chromosomes in the genera Acantholimon and Dorema.

scholarly journals Chromosome numbers of some species of Pteris (Pteridaceae) in Java, Indonesia

2018 ◽  
Vol 19 (6) ◽  
pp. 2118-2126
Author(s):  
TITIEN NGATINEM PRAPTOSUWIRYO ◽  
MUGI MUMPUNI
Keyword(s):  
Chromosome Number ◽  
Morphological Variation ◽  
Chromosome Numbers ◽  
Diploid Species ◽  
Somatic Chromosome Number ◽  
Chromosome Counts ◽  
Ploidy Levels ◽  
Central Java ◽  
Fern Species ◽  
Pteris Multifida

Praptosuwiryo TNg, Mumpuni M. 2018. Chromosome numbers of some species of Pteris (Pteridaceae) in Java, Indonesia. Biodiversitas 19: 2118-2126. Pteris L. (Pteridaceae) is a large fern genus consisting of about 250 species which distributed predominantly in tropical and subtropical countries. The genus grows in a diversity of ecosystems, either terrestrially or lithophytically, although most species occur in the forest. A study of the cytology of Pteris in Java is being undertaken for the conceptual understanding of the interrelationships between various fern species in the Malesian region. This aims of our study are: (1) to observe somatic chromosome number of some species of Pteris in Java; (2) to determine the reproduction types of the observed species by counting the spore number per sporangium; (3) to discuss polyploidy in the species in relation to plant morphological variation across their geographical distribution. Chromosome counts for eight species are reported. Pteris biaurita is an apogamous diploid species (2n = 58). Pteris ensiformis var. ensiformis has chromosome numbers of 2n = 87 (apogamous triploid) and 2n = 116 (sexual tetraploid), while                 P. ensiformis var. victoriae has a chromosome number 2n = 58 and is a sexual diploid. Pteris fauriei is an apogamous triploid species (2n = 87). Pteris longipinnula has a chromosome number of 2n = 116 (tetraploid). Pteris multifida and P. vittata are sexual tetraploids (2n=116). Pteris tripartita has two ploidy levels (sexual diploid and tetraploid). Another currently unplaced Javanese Pteris sp. has 2n = 87 (apogamous triploid). Diploid P. biaurita, tetraploid P. ensiformis, triploid P. fauriei, diploid P. tripartita, and teraploid P. vittata are new record cytotypes for Central Java. Polyploidy in the genus in relation to plant morphological variation across its geographical range is discussed.

scholarly journals Genome Size Estimates and Chromosome Numbers of Callicarpa L. (Lamiaceae)

HortScience ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 567-570 ◽  
Author(s):  
Ryan N. Contreras ◽  
John M. Ruter
Keyword(s):  
Flow Cytometry ◽  
Chromosome Number ◽  
Genome Size ◽  
Chromosome Numbers ◽  
Chromosome Counts ◽  
Ploidy Levels ◽  
Flow Cytometry Data ◽  
Carbol Fuchsin ◽  
Cross Compatibility ◽  
Size Estimates

Genome size estimates and chromosome number information can be useful for studying the evolution or taxonomy of a group and also can be useful for plant breeders in predicting cross-compatibility. Callicarpa L. is a group of ≈140 species with nearly worldwide distribution. There are no estimates of genome size in the literature and the information on chromosome numbers is limited. Genome size estimates based on flow cytometry are reported here for 16 accessions of Callicarpa comprising 14 species in addition to chromosome counts on six species. Chromosome counts were conducted by staining meristematic cells of roots tips using modified carbol fuchsin. Holoploid genome size estimates ranged from 1.34 pg to 3.48 pg with a mean of 1.74 pg. Two tetraploids (2n = 4x = 68; C. salicifolia P'ei & W. Z. Fang and C. macrophylla Vahl GEN09-0081) were identified based on holoploid genome size and confirmed by chromosome counts. There was little variation among species for monoploid genome size. 1Cx-values ranged from 0.67 pg to 0.88 pg with a mean of 0.77 pg. Chromosome counts for six species revealed a base chromosome number of x = 17. Callicarpa chejuensis Y. H. Chung & H. Kim, C. japonica Thunb. ‘Leucocarpa’, C. longissima Merr., and C. rubella Lindl. were confirmed as diploids (2n = 2x = 34). Cytology supported flow cytometry data that C. salicifolia and C. macrophylla GEN09-0081 were tetraploids. The two accessions of C. macrophylla included in the study were found to be of different ploidy levels. The presence of two ploidy levels among and within species indicates that polyploidization events have occurred in the genus.

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