Somatic Chromosome Number Of 2n Research Articles

Karyotype asymmetry in some Scilloideae (Hyacinthaceae) members from Algeria

This cytogenetic study attempts to shed light on the karyomorphological and asymmetry data of species in the subfamily Scilloideae previously included in Scilla, namely Hyacinthoides lingulata (Poir.) Rothm., Prospero autumnale (L.) Speta, Prospero obtusifolium (Poir.) Speta, Barnardia numidica (Poir.) Speta, and Oncostema elongata (Parl.) Speta. These taxa are predominantly from the Skikda region (northeastern Algeria). H. lingulata had a somatic chromosome number 2n=2x=16, P. autumnale 2n=2x=14, P. obtusifolium 2n=2x= 8, B. numidica 2n=2x=18, and O. elongata 2n=2x=16. The indices of intrachromosomal (MCA, A1, and AsI) and interchromosomal (CVCL, CVCI, and A2) asymmetry revealed that H. lingulata has the most asymmetrical karyotype (1C), while P. autumnale has the most symmetrical karyotype (3A). P. obtusifolium has a relatively symmetrical karyotype (4A), while B. numidica and O. elongata have both an asymmetrical karyotype (1B). These findings differ from those previously reported for the same taxa in Algeria, hence indicating the substantial genetic variation that exists within the country.

Karyotypes and Physical Mapping of Ribosomal DNA with Oligo-Probes in Eranthis sect. Eranthis (Ranunculaceae).

A comparative karyotype analysis of four species of yellow-flowered Eranthis sect. Eranthis, i.e., E. bulgarica, E. cilicica, E. hyemalis, and E. longistipitata from different areas, has been carried out for the first time. All the studied specimens had somatic chromosome number 2n = 16 with basic chromosome number x = 8. Karyotypes of the investigated plants included five pairs of metacentric chromosomes and three pairs of submetacentric/subtelocentric chromosomes. The chromosome sets of the investigated species differ mainly in the ratio of submetacentric/subtelocentric chromosomes, their relative lengths, and arm ratios. A new oligonucleotide probe was developed and tested to detect 45S rDNA clusters. Using this probe and an oligonucleotide probe to 5S rDNA, 45S and 5S rDNA clusters were localized for the first time on chromosomes of E. cilicica, E. hyemalis, and E. longistipitata. Major 45S rDNA clusters were identified on satellite chromosomes in all the species; in E. cilicica, minor clusters were also identified in the terminal regions of one metacentric chromosome pair. The number and distribution of 5S rDNA clusters is more specific. In E. cilicica, two major clusters were identified in the pericentromeric region of a pair of metacentric chromosomes. Two major clusters in the pericentromeric region of a pair of submetacentric chromosomes and two major clusters in the interstitial region of a pair of metacentric chromosomes were observed in E. longistipitata. E. hyemalis has many clusters of different sizes, localized mainly in the pericentromeric regions. Summarizing new data on the karyotype structure of E. sect. Eranthis and previously obtained data on E. sect. Shibateranthis allowed conclusions to be formed about the clear interspecific karyological differences of the genus Eranthis.

Chromosome numbers in 31 taxa of Asteraceae, Brassicaceae, Poaceae, Hypericaceae, Lamiaceae, Fabaceae and Plantaginaceae from wetlands of Hamadan region in Iran

In this study, we report the somatic chromosome numbers (2n) of 31 taxa belonging to Asteraceae, Brassicaceae, Poaceae, Hypericaceae, Lamiaceae, Fabaceae and Plantaginaceae families from wetlands of Hamadan region in Iran. The chromosome numbers of about half of these species have not been reported in the previous literature. Chromosome number of Ononis spinosa counted chromosomally for the first time at the world level and the chromosome numbers of Erigeron acer, Pulicaria dysenterica, Arctium lappa, Xanthium strumarium, X. spinosum, Barbarea plantaginea, Brachypodium sylvaticum, Polypogon fugax, Prunella vulgaris and Lathyrus chloranthus, are here reported for the first time from Iran. In all taxa 2n was 12, 14, 16, 18, 20, 24, 28, 30, 32 and 42, as a diploid, tetraploid and hexaploid levels. These newly available data are further compared with those previously published for the same or related species.

Karyotype characterization of three important aromatic Cinnamomum L. species with special emphasis on reversible chromosome banding

Conventional stain (orcein) and DNA base-specific fluorochromes (CMA and DAPI) were used to characterize three medicinally and economically important aromatic Cinnamomum L. species namely, C. camphora, C. tamala and C. zeylanicum. Despite having identical somatic chromosome numbers 2n = 24, the studied Cinnamomum L. species had distinct centromeric formulae, such as 24m in C. camphora, 18m + 6sm in C. tamala, and 8m + 16sm in C. zeylanicum. When karyotype assessment criteria were taken into account, these three studied species also displayed distinctiveness, and C. zeylanicum represented a more heterogeneous karyotype than the other two species. The karyotypic diversification was reflected in the symmetry classes of Stebbins’ classification, with C. camphora and C. tamala having 1B karyotype while C. zeylanicum was found to have a 2A karyotype. CMA- and DAPI-banding patterns of these species were different and species-specific regarding the number, location and percentages of GC- and AT-rich repetitive sequences in the genome. Reversible fluorescent banding patterns revealed the stain-specific nature of satellite in C. camphora L. By comparing karyotypic traits and reversible fluorescent banding patterns, characterization was thereby encountered for three Cinnamomum L. species from Bangladesh.

Assessing karyotype diversity in the genus Lathyrus L. (Fabaceae)

AbstractAlthough substantial information on the karyological measures of Lathyrus is available, no study has collected and analysed such data to assess the relationship among its taxa. Hence, the present study examined the degree and trends of chromosome diversity in this genus in congruence with Kupicha's sectional classification. Karyo‐morphological data for 74 species representing 11 sections of Lathyrus were collected through the literature survey. The karyological measures included were the total haploid chromosome length (THL), somatic chromosome number (2n), basic chromosome number (x), and five other parameters of karyotype asymmetry (CVCL, CVCI, MCA, A1, and A2). Basic chromosome number (x = 7) and somatic chromosome number (2n = 14) remained stable throughout the genus. Mean karyotypes revealed marked variations in karyotype structure among the 11 sections of Lathyrus. Further, key differences were identified during comparisons of various measures of karyotype asymmetry. Phylogenetic and principal coordinate analyses exhibited substantial variation among different sections of Lathyrus and out‐group genera. Overall, current findings indicated that the karyotype asymmetry measures can serve as an efficient tool to assess the relationship among different sections of Lathyrus.

In vitro propagation and cytogenetic stability of Tripleurospermum insularum (Asteraceae) – a critically endangered insular endemic species from Turkey

Tripleurospermum insularum (Asteraceae) is a critically endangered (CR) insular endemic species in Turkey and is facing high risk of extinction. Here, a rapid and efficient in vitro propagation protocol using nodal segments obtained from seedling shoots cultured on Murashige and Skoog (MS) basal medium supplemented with different plant growth regulators (PRGs) was developed to conserve T. insularum. Besides, the cytogenetic fidelity of propagated plants was tested with DNA ploidy level using flow cytometry (FCM) as well as chromosome counting. The highest shoot number and length of shoot per explant were achieved in MS medium containing 4.6 µM zeatin (ZEA) and 0.5 µM indole-3-acetic acid (IAA). No variation in DNA ploidy level (2x) and somatic chromosome number (2n = 18) of all propagated plants were observed. In vitro rooting of shoots was achieved at 100% efficiency in the medium supplemented with 2.9 µM IAA. The rooted plantlets were transferred ex vitro with 74% survival. This is the first report of a successfully developed micropropagation protocol for ex situ conservation of T. insularum.

Karyotype and genome size variation in white-flowered Eranthis sect. Shibateranthis (Ranunculaceae).

Comparative karyomorphological analyses of six out of the eight white-flowered species of Eranthissect.Shibateranthis have been carried out. All studied specimens of E.byunsanensis, E.lobulata, E.pinnatifida, and E.stellata had a somatic chromosome number 2n = 16 with basic chromosome number x = 8. On the contrary, E.tanhoensis and E.sibirica had a basic chromosome number x = 7. The specimens of E.tanhoensis were diploid with 2n = 14, while the specimens of E.sibirica were polyploid with 2n = 42. Monoploid chromosome sets of the investigated diploid species had 4–5 metacentric chromosomes and 2–4 submetacentric/subtelocentric/acrocentric chromosomes. The highest level of interchromosomal asymmetry, estimated via CVCL, was found in E.byunsanensis and E.pinnatifida. The highest levels of intrachromosomal asymmetry (MCA) and heterogeneity in centromere position (CVCI) were found in E.lobulata and E.byunsanensis, while E.sibirica had the most symmetric karyotype. A multivariate PCoA analysis of basic karyotype parameters (2n, x, THL, CVCL, MCA, and CVCI) highlighted no overlap among species accessions, which was also confirmed by LDA. The average absolute monoploid DNA content (1Cx) of the 23 investigated samples of six Eranthis species varied from 9.26 ± 0.25 pg in E.sibirica to 15.93 ± 0.32 pg in E.stellata. Overall karyological affinity was highlighted between E.lobulata and E.stellata, on one side, and between E.byunsanensis and E.pinnatifida, on the other side. Interestingly, there was no significant correlation between total haploid (monoploid) chromosome length (THL) and 1Cx values in these species.

Development of interspecific hybrid progenies of mango and their characterization

A total 26 interspecific mango hybrids population were obtained from the crosses involving Alphonso, Amrapali and NR34 as a female parents and Mangifera odorata Griff, as male parent. Morphological traits revealed that all the interspecific hybrids as well as parent trees were found to be erect and also spreading habit with circular, semicircular and oblong crown shape. The results of cytological studies showed that interspecific hybrids were also possessed the same somatic chromosome number 2n = 40 as that of mango. Most of the interspecific hybrids showed the intermediate to dense foliage density. Out of 11 SSR markers, three primers showed high polymorphism and confirmed the hybridity based on the allelic range variation among the four parental mangoes.

Curculigo sabui sp. nov. (Hypoxidaceae), a new species from Balaghat Ranges of Maharashtra, India

A new species, Curculigo sabui S.P.Gaikwad & Gore is described from margins of temporary fresh water streams in Yedshi‐Ramling Wild Life Sanctuary of Balaghat Ranges of Maharashtra, India. Morphologically it resembles Curculigo janarthanamii Gore & S.P.Gaikwad and C. multiflora Zimudzi but differs in having elliptic‐lanceolate to obovate (20–52 × 3.0–4.5 cm) leaf lamina, flowers three to five in umbel‐like racemes or sometimes solitary, seed coat with irregular striations and somatic chromosome number 2n = 36. A detailed morphological description with line drawings, photographs and comparative account of the species is provided here.

Кариосистематическое изучение рода Eranthis Salisb. (Ranunculaceae)

Изучены кариотипы четырех видов рода Eranthis: E. hyemalis, E. lobulata, E. longistipitata и E. stellata. Для E. lobulata и E. longistipitata данное исследование выполнено впервые. Все изученные образцы имелисоматическое число хромосом 2n = 16. Кариотипы исследованных видов содержат пять пар равноплечих (метацентрических) хромосом и три пары неравноплечих (субметацентрических, субтелоцентрических, телоцентрических) хромосом. Основное различие хромосомных наборов данных видов заключается в типах неравноплечиххромосом. Различия в кариоморфологических параметрах у изученных видов согласуются с разделением рода насекции по морфологическим признакам.

Cytogenetical Analyses of some species of the genus Sisymbrium (Brassicaceae) in Turkey

In this study, karyotype analyses of three species belonging to the genus Sisymbrium L. (Brassicaceae) and grown naturally in Turkey were conducted. These taxa are S. officinale (L.) Scop., S. runcinatum Lag. ex DC. and S. orientale L. The somatic chromosome number of 2n = 14 was reported for all species. Total chromosome lengths are between 1.33 and 2.43 µm in S. officinale, 1.30 and 2.48 µm in S. orientale, 1.02 and 2.18 µm in S. runcinatum. The karyotypes are as follows: S. officinale consists of 12m + 2sm, S. orientale consists of 10m + 4sm and S. runcinatum consists of 10m + 4sm chromosome pairs. S. runcinatum is the most asymmetrical karyotype based on all index values.

First record of Melampodium divaricatum (Asteraceae) in West Tropical Africa

A plant that showed morphological closeness to Aspilia africana (Pers) C. D. Adams (Asteraceae) was spotted and collected in 2015 along Afe Babalola University road, Ado‐Ekiti, Ekiti State, Nigeria with coordinates 7°36′59.99″N, 5°12′60.00″E. However, upon closer observation some distinct and peculiar characteristics that clearly distinguished it from Aspilia africana were revealed, e.g. sterility of the disc florets and production of achenes by ray florets only. Another striking character of the plant was total emptying of the capitulum after achene maturation, leaving an empty capitulum cup on the plant. Literature and herbarium searches revealed that the plant had neither been reported from West Tropical Africa nor collected in any herbarium in Nigeria before. The plant was eventually identified as Melampodium divaricatum (L.) which is an annual erect herb, distributed in tropical and subtropical regions but mostly restricted to Mexico, North America and Central America. Morphological, reproductive and cytological studies carried out on the plant revealed it to possess a highly branched erect pigmented stem, simple opposite sub sessile leaves with acute apex and distantly serrated margins, capitula with yellow unisexual disc and ray florets, sterile disc florets, fertile ray florets, relatively high pollen fertility (92.85%), a somatic chromosome number of 2n = 24 and regular formation of 12 bivalents, indicating the plant to be a diploid species. Further studies on Melampodium in Nigeria and a general revision of the flora of West Tropical Africa is suggested as well as the need to monitor M. divaricatum in the region since it appears to have the capacity to become invasive.

Extended centromere and chromosomal mosaicism in some varieties of grass pea, Lathyrus sativus L.

An abnormal mitotic behavior revealing chromosomal mosaicism was observed in two among the three studied cultivars (cv. Nirmal, cv. Prateek and cv. Ratan) of Lathyrus sativus. Several numerical variants of chromosome complement were detected in the different cells coexisted with normal diploid cells in the somatic tissue of the same root-tip. Somatic chromosome number 2n = 14 were found with the greatest frequency (67%); however, a spectrum of quite low percentage of discordant and variable chromosome numbers especially of aneuploidy mode, ranging from 2n = 11 (9.6%), 2n = 12 (8.7%), 2n = 13 (4.7%) and 2n = 15 (10.3%) in Nirmal cultivar were observed. In Prateek cultivar, the most interesting cytological character is that karyotype though symmetrical but indicating transition between symmetrical to asymmetrical is slightly bimodal due to presence of one pair of very small chromosomes. In general, most of the chromosomes of all cultivars were nearly median centromered. Although the cv. Ratan shows the normal chromosome number, but in 4 pairs of chromosomes, the centromere region appeared unusually ‘extended’. In Nirmal and Prateek cultivars karyotype, the secondary constriction is proximal on the short arm whereas, in some other metaphase plates, the same constriction bearing macrosatellite is on the long arm of bigger nearly submedian chromosome of pair one. We propose that the differences in satellite position arose by karyotype rearrangements; probably involving translocations. At the same time, extended centromeres may be due to the activities of retrotransposons at the centromere region of the said chromosome of cv.Nirmal.

Correlating karyomorphology and molecular marker analyses in turmeric: a case study

ABSTRACT India is the largest producer and exporter of turmeric (Curcuma longa), and different cultivars of this crop are traditionally characterized using agronomic traits, such as rhizome weight, yield potential, color and aroma of rhizome, curcumin content, and stability of curcumin content, which are influenced by environmental factors. The purpose of the present study was to probe whether karyomorphological and molecular marker attributes of turmeric cultivars could be correlated to validate their distinctiveness. Detailed karyomorphological analyses revealed uniform somatic chromosome number (2n = 63), with symmetric karyotype in all the studied cultivars. Chromosomes varied from 0.67 to 2.03 µm in length, with up to 72% bearing primary constrictions in the nearly median region (i-value ranging from 27.17 to 50). Asymmetry indices also indicated overall karyotypic symmetry among cultivars. On the contrary, random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) marker analyses revealed significant variability in the genetic constitution among them; Jaccard’s similarity coefficient value ranged from 0.569 to 0.969. Unweighted pair group method with arithmetic average (UPGMA) dendrogram and principal coordinate analysis based on the Jaccard’s coefficient produced four distinct clusters, which showed no geographical bias. Thus, it was concluded that although significant genetic variability that exists among the turmeric cultivars can be utilized for examining their authenticity, practicality of the use of karyomorphological characters for identification is significantly limited by the gross karyotypic similarity. Cryptic genetic changes accumulate in the genome of these plants because of their interaction with the environment. However, these remain confined within each cultivar in the absence of large-scale hybridizations and predominant vegetative propagation. This probably leads to variability in agronomic characters and may even help in developing novel characters in different cultivars. However, detection of any such change in the chromosomal structure would require fluorescent hybridization techniques.

Karyotype and Stomatal Studies on Three Genotypes of <i>Morus</i> spp.

Three mulberry genotypes viz., MR2, C763 and Morus macroura were analyzed for the stomatal frequency and karyotypic attributes. MR2 and C763 were found to be diploids with somatic chromosome number of 2n=28, while variety Morus cathyana revealed tetraploid chromosome number of 2n=56. Somatic chromosomes measured 1.26 to 2.86µm in length. Karyotypes of these taxa are symmetric. Only metacentric and sub-metacentric chromosomes are found in the complement. Stomatal frequency was found to be high in diploid mulberry varieties compared to tetraploid variety. © 2017 The Japan Mendel Society.

First genome size assessment in the genus Peganum and inthe family Nitrariaceae: Iberian and North African data on Peganum harmala,including an intensive sampling in Tunisia

Peganum harmala is a halonitrophilous perennial herb that is relevant in the landscape of steppe, semidesert, and desert territories in southern Europe, northern Africa, and southwestern Asia. We present here data on the nuclear DNA amount assessment in one Iberian and 17 Tunisian populations of this species. The 2C values, belonging to the very small genome category, ranged from 0.61 to 0.67 pg. These data are the first on genome size for the species and for the whole genus and the whole family. In addition, the somatic chromosome number (2n = 24) has been counted in one population, confirming previous reports and constituting the first one in a Tunisian accession of the species. The results show a high degree of homogeneity of the character studied within the species. These new data, filling a gap in genome size knowledge at family level, together with the specific homogeneity in genome size in a large area, could be relevant for further large-reach analyses on genome size evolution.

Nuclear and cytoplasmic contributions from Erianthus arundinaceus (Retz.) Jeswiet in a sugarcane hybrid clone confirmed through genomic in situ hybridization and cytoplasmic DNA polymorphism

A hybrid between Erianthus arundinaceus (Retz.) Jeswiet and Saccharum spontaneum L. which are wild related species of sugarcane (Saccharum L., Family Poaceae), was repeatedly crossed as female parent with sugarcane commercial varieties to develop near commercial sugarcane clones. The cytoplasm type of the hybrid derivatives were confirmed to be of E. arundinaceus through the mitochondrial and chloroplast DNA polymorphism of nad 4/3-4 intron segment and psbC–trnS segment, respectively. The E. arundinaceus × S. spontaneum hybrid with somatic chromosome number 2n = 62 was confirmed to have 30 chromosomes from E. arundinaceus through genomic in situ hybridization (GISH). The (E. arundinaceus × S. spontaneum) × sugarcane hybrid (2n = 118) had 24 chromosomes from E. arundinaceus whereas its next generation hybrid with sugarcane (2n = 108) had only 12 Erianthus chromosomes. The commercial sugarcane hybrid Co 15015, which is the third generation hybrid with 2n = 106 was confirmed to have two E. arundinaceus chromosomes through GISH. It is the first report of sugarcane with both alien cytoplasm and chromosome contributions from E. arundinaceus.

Genome Characterization of In Vitro Induced Amphiploids of an Intergeneric Hybrid Erianthus arundinaceus × Saccharum spontaneum

Erianthus arundinaceus, a wild relative of sugarcane, has great potential as a germplasm source to contribute valuable traits to sugarcane including better ratoonability, vigour and adaptation to biotic and abiotic stresses. Many unsuccessful attempts have been made to introduce the desirable characters from this wild species to modern sugarcane cultivars. In most of these cases, it was constrained by lack of fertility. A rare hybrid between E. arundinaceus (IK 76–78, 2n = 60) × Saccharum spontaneum (Iritty-2, 2n = 64) has been developed as an intermediate hybrid to transfer the characters from E. arundinaceus to sugarcane cultivars. This hybrid, CYM 04-420, with somatic chromosome number 2n = 62 was subjected to in vitro colchicine treatment, and amphiploids were developed with 2n = 124. We report here for the first time the chromosome composition and chromosome pairing behaviour of S. spontaneum × E. arundinaceus intergeneric amphiploid via genomic in situ hybridization. The implications of the results from this study for introgression of genes from E. arundinaceus in sugarcane breeding programmes are discussed in the paper.

Anatomical, palynological and karyological remarks of Silene brevicalyx and Silene ozyurtii (Caryophyllaceae)

Anatomical, palynological, karyological and morphological seed characters of Silene brevicalyx and S. ozyurtii (Caryophyllaceae) were investigated for the first time. S. brevicalyx grows on serpentine rocky slopes and open forest in Muğla province (southwestern Turkey), while S. ozyurtii is an East Mediterranean element growing on serpentine stony slopes and again open forest. Anatomically, cross-section of root of both species have a periderm as the protective tissue at the outermost layer and locally druse crystals are encountered in cortex layer. Stems have a thick well-developed sclerenchyma layer. The walls of outward sclerenchyma cells are wider than the walls of inward cells. Leaves are equifacial. Pollen are prolate-spheroidal, symmetry radially, polarity apolar, with aperture periporate, ornamentation microechinate-perforate. Seeds of both species are reniform, with surface concave and granulation coarse-medium, hylar zone recessed, dark-brown or fuscous coloured. Somatic chromosome numbers of 2n = 24 were found for both taxa. The karyotypes are analyzed for the first time for S. brevicalyx and S. ozyurtii. Ideograms of these taxa were drawn by use of an Image Analysis System.

Evaluation of genetic diversity in some promising varieties of lentil using karyological characters and protein profiling.

Somatic chromosome study from root tip cells using the squash technique of the cytological method and seed protein profile of 5 varieties of Lens culinaris (Lentil) through SDS–PAGE were investigated. Karyotype analysis showed gross uniformity in morphology. Somatic chromosome number 2n = 14 is constant for all the varieties. Chromosomes are mostly long to medium in length with secondary constrictions in one pair of chromosome. Primary constrictions in chromosome ranged from nearly median to nearly submedian in most of the cases. Notwithstanding the gross homogeneity, karyotype analysis revealed minute differences in details. Each lentil variety is thus characterized by its own karyotype, serving as one of the identifying criteria. The seed protein profile revealed that varieties are very close to each other with respect to similarity index that ranged from 0.594 to 0.690. With regard to seed protein banding patterns, slight polymorphism (14.285%) indicating low genetic diversity has been identified among the 5 varieties. A dendrogram indicates one variety is plesiomorphic and rest varieties are apomorphic. All the experimental varieties of lentil studied here show low genetic diversity due to their similar genetic base, indigenous genetic resources and conservative nature of the seed protein.