Aneuploidy and karyotypic polymorphism in 98 individuals of Lysimachia mauritiana collected in middle and southern parts of the Ryukyu Archipelago, Okinawa Pref., were cytologically analyzed. Aneuploids of 2n=16, 17, 18, 19 and 20, and 13 cytotypes were recognized in the areas. By using longer metacentric chromosomes as markers, the number of all cytotypes in the Ryukyu Archipelago, Japan was 18, together with data reported earlier.
We have recorded the meiotic chromosome counts in 2 species, Vicia rigidula (n=12) and V. tenera (n=7) from the cold desert region of Kinnaur district of Himachal Pradesh (India). V. rigidula which exists at tetraploid level (x=6) and depicts the phenomenon of cytomixis involving chromatin transfer in 6.52% of the observed pollen mother cells (PMCs) during different meiotic stages. 3.43–12.20% of PMCs also show non-synchronous disjunction of a few bivalents, laggards and chromatin bridges during anaphases/telophases, and micronuclei and included micronuclei in tetrads. Products of such aberrant PMCs result in the formation of sterile/unstained pollen grains and fertile/stained pollen grains of variable sizes. The meiotic course in V. tenera, which is diploid (x=7), depicts normal meiotic behaviour in the majority of the PMCs. Only a few PMCs (0.20–1.20%) depict some meiotic disturbances during anaphases resulting in the formation of 6.00–7.20% sterile/unstained pollen grains.
This paper succeeded in discovering the polymorphism of nucleolar organizer regions (NORs) and whole-arm translocation (WAT) between chromosomes 8 and 9 of the lowland agile gibbon (Hylobates agilis unko) in Thailand, after standard whole blood lymphocyte culture and G-banding technique were applied to stain the chromosomes. The results showed that the 2n of H. agilis unko was 44. The type of autosomes were 28 metacentric, 12 submetacentric and 2 acrocentric chromosomes, with the X and Y-chromosome being submetacentric and acrocentric chromosome, respectively. In addition, a pair of the long arms of chromosome 12 showed clearly observable NORs. This is the first report on the polymorphism of NORs in H. agilis unko. The results show a heteromorphism in female with a difference size of NORs of chromosome 12, while in males show an equal size of both chromosome 12 with a homomorphism. We also detected a WAT between chromosomes 8 and 9 in H. agilis unko and found that both male and female chromosomes 8 and 9 were 8c′ (homomorphism, 8c′8c′) and 9′ (homomorphism, 9′9′), respectively, resulting from pericentric inversion and followed by reciprocal translocation.
This work is the first description of a cytogenetic study of the Indian muntjac (Muntiacus muntjak) in Laos PDR. Blood samples were taken from 1 male and 1 female Indian muntjac kept in Laos Zoo, Laos PDR. Lymphocytes were cultured following standard methods. Cell harvesting was performed and followed by metaphase chromosome spreading on microscopic slides. Conventional staining, G-banding and high-resolution techniques were then applied using Giemsa's stain. The results showed that the number of diploid chromosomes (2n) of the Indian muntjac was 6 in female and 7 in male. The short arm of chromosome pair 3 referred to the X chromosome. Idiograms represent the banding pattern at the metaphase chromosome and prometaphase chromosome were 149 and 192 bands, respectively. The polymorphism of nucleolar organizer regions (NORs) was found at 2 sites on chromosome pair 1, and 1 site on chromosome pair 3 (heteromorphic, 3a3b) in the female, whereas they were found at 2 sites on chromosome pair 1 and 2 sites on chromosome pair 3 (homomorphic, 3a3a) in the male. These results will be useful for providing basic genetic information and future studies of the breeding, conservation and chromosome evolution in this animal.
Chromosomal studies on Clematis montana from Dalhousie hills, Himachal Pradesh, India have led to the identification of an accession that exhibited aberrant male meiosis, pollen sterility and heterogeneous sized fertile pollen grains. The accession, which exists at diploid level (n=8), depicts the phenomenon of cytomixis involving chromatin transfer among proximate meiocytes (PMs). The chromatin transfer in the PMCs has also caused various meiotic irregularities like chromatin stickiness, interbivalent connections, unorganized and pycnotic chromatin, laggards/chromatin bridges during anaphases/telophases, micronuclei and included micronuclei in microspores, triads and polyads. Consequent to cytomixis and associated meiotic irregularities, the products of PMCs result in some pollen sterility and variable sized fertile pollen grains. Though the Cytological status of such variable sized pollen grains could not be ascertained at present, the large sized pollen grains, which are almost double sized, may be of ‘2n’ constitution and play an important role in the origin of intraspecific polyploidy in the species. The small sized fertile pollen grains which are the products of hypoploid PMCs could lead to the origin of aneuploids. Similar effects of cytomixis on meiotic course resulting in pollen malformation have been reported earlier in a number of species by the authors from this laboratory.
The meiocytes of Uraria picta (Jacq.) DC (Family: Leguminosae; Papillionoide; annual medicinal herb) had n=11 chromosomes with an average chromosomal association of 0.11 IV+10.29 II+0.98 I per cell at diakinesis and metaphase I. The bivalents formed rods (rods: 1–11/cell, 6.95±0.22; rings: 0–9/cell, 3.59±0.25/cell) mostly at MI with mean chiasma of 14.22±0.24 (8 to 20) per cell. Formation of 11 II in PMCs was predominant (62.71%). About 11.25% of the cells had a ring quadrivalent. All AI cells were cytologically balanced (11/11) with an average pollen fertility of 97.58%. A persistant feature in 100% diakinesis and MI cells was the presence of secondary association of chromosomes and the chromosomes assorted themselves into variable groups of 2 (0.85%), 3 (5.08%), 4 (7.63%), 5 (11.86%), 6 (42.37%), 7 (19.49%), 8 (3.39%), 9 (2.54%) and 11 (1.69%). Out of 52 different chromosomal associations among the group classes, 3 II(1)+2 II(3)+1 II(2)−16.10% (6 group class) was most frequent.
Detailed analysis of chromosome number and karyotype in new cultivars of brinjal (Solanum melongena var. esculentum) cv. Utkal Anushree, cv. Utkal Jyoti, cv. Utkal Madhuri, cv. Utkal Keshari and cv. Utkal Tarini were carried out. The somatic chromosome number 2n=24 was recorded in all the cultivars with significant structural differences in chromosome compliment. Total chromosome length varied from 82.54 μm to 94.24 μm and 42.51 μm3 to 48.53 μm3 in cv. Utkal Anushree and cv. Utkal Jyoti respectively. Total F% revealed asymmetric karyotype mostly with median constricted chromosomes. Genome size varied from 7.10 pg to 9.24 pg; having 6958 Mbp to 9055 Mbp in cv. Utkal Anushree and cv. Utkal Tarini showed significant correlations with chromosome length and chromosome volume. Karyotype and genomic analysis helped in distinguishing purple coloured skin fruit type cv. Utkal Tarini and cv. Utkal Kehari with green colour skin fruit types cv. Utkal Anushree and cv. Utkal Madhuri of brinjal.
Meiotic behavior of 7 Iranian populations of 5 Astragalus species from the section Megalocystis, A. submitis Boiss. & Hohen., A. raddei Basil., A. halicacabus Lam., A. ebenoides Boiss. and A. fuhsii Freyn & Sint. is presented. All species are diploid and possess 2n=2x=16 chromosome number, consistent with the proposed base number of x=8 from ICPN. Although the taxa displayed regular bivalent pairing and chromosome segregation at meiosis, some meiotic abnormalities observed include a varied degree of fragmented chromosomes in metaphase I; cytomixis in metaphase I; asynchronous nucleus in metaphase II and cytomixis in telophase II.
The present study documents the presence of 3 B chromosomes in safflower, which is one of the first such reports. During the present investigation, B chromosomes were found to induce a twofold effect on planting, firstly a reduction in chiasma frequency in euchromatic region, and secondly depression in the percentage of pollen fertility due to an increase in the number of unpaired chromosomes. Although the presence of Bs depressed the chiasma frequency of the regular complement, the frequency of A and B chromosomes does not appear to be related. No correlation between B chromosomes and phenotype has been reported. Thus, it can be predicted that the presence of additional DNA as B chromosomes can bring about some structural or numerical changes in the long run and may affect the genetic integrity of the plant and thus result in a changed genotype with negligible effect on the morphology and vigor of the plant.
Meiotic studies were performed in 9 Oryzopsis species of O. pubiflora, O. lateralis, O. holciformis, O. barbellata, O. munroi, O. microcarpa, O. sphacelata, O. virescense and O. molinioides showing the presence of 2n=2x=24 in all nine species studied. The species studied were diploid and had 12 chromosome number, and in O. microcarpa, O. sphacelata, O. molinioides and O. virescense chromosomes are new count. B-chromosomes 0–2 were observed in all species studied, which were smaller than A-chromosomes and did not pair with them. T-test analysis between the cells with B-chromosomes and those devoid of Bs showed significant difference in chiasma frequency and distribution as well as in chromosomes pairing only in O. munroi, with significant reduction in meiotic values in the presence of B-chromosomes. The occurrence of large pollen grains (possibly unreduced pollen grains) was observed along with small (normal) pollen grains in these species. Significant difference observed in chiasma frequency and distribution among species studied may be of use in species delimitation. Moreover species relationships obtained based on cytological data partly supports taxonomic treatment of the genus.
Protocol has been standardized for micropropagation of medicinally important Curcuma caesia using sprouted bud explants from rhizome. Tissue culture raised plantlets of C. caesia could be conserved in vitro through subculturing at an interval of 4 months. The genetic stability of micropropagated plants was studied with an interval of 6 months up to 30 months in culture using cytophotometric, random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) analysis. Cytophotometric analysis of 151 plants revealed a unimodal distribution of the DNA content with a peak corresponding to 4C nuclear DNA (3.5 pg). RAPD and ISSR analysis revealed mopnomorphic bands showing the absence of polymorphism in all 73 regenerants analyzed, thus confirming the genetic uniformity among in vitro grown somaclones of Curcuma caesia.
Two wild jute species, namely Corchorus trilocularis and C. pseudo-olitorius, were investigated after staining with orcein, CMA and DAPI. In addition, activities of 3 isozymes viz. esterase, acid phosphatase and peroxidase were studied. These 2 spp. were found to possess 2n=14 chromosomes. Satellites were observed only in C. pseudo-olitorius. The staining property of satellites was striking since a pair appeared in orcein, 2 pairs in CMA and none in DAPI-staining. Each species possessed distinct CMA and DAPI banded karyotypes. Moreover, different activities of acid phosphatase, peroxidase and esterase were found in these 2 species. Fluorescent banding and isozyme analysis showed that C. pseudo-olitorius and C. trilocularis are completely different species.
The study on chromosomal staining comparison of plant cells with natural dyes was carried out to compromise the use of expensive dyes. Dyes from black glutinous rice (Oryza sativa L.) and Lac (Laccifer lacca Kerr) were extracted using acetic acid, ethanol, butanol and hexane with the concentration levels of 30%, 45% and 60%, respectively. The pH was then adjusted from 1 to 7, the natural extracted dyes were used to stain the chromosomes of spider lily (Hymenocallis littoralis Salisb.) root cells, which were ongoing mitotic cell division, using the squash technique. The results showed that the natural extract dyes were capable of chromosome staining and cell division observing. Natural dyes which showed well-stained chromosome included 45% acetic acid-extracted black glutinous rice dye (pH 1–3), 45% butanol-extracted black glutinous rice dye (pH 1–3) and 60% ethanol-extracted Lac dye (pH 1–3). We also concluded that all other extracts have no significant quality as chromosomal staining indication.
The karyological data of 7 species of Allium represents information in 2 parts of Iran: East Azerbaijan and Kurdistan is reported here with the basic chromosome number x=8. Most of the karyotypes are symmetrical consisting of metacentric and submetacentric chromosomes. According to the results of this study A. rubellum species is diploid so that its karyotype consists of 16 chromosomes (2n=2x=16) whose sizes are between 8.084–10.268 μm, and chromosomes pairs No. 2 and 3 includes satellites. All of the chromosomes were metacentric type. A. longicuspis species, as this study explains, is tetraploid and its karyotype includes 32 chromosomes (2n=4x=32) of sizes of 4.912–7.462 μm. Chromosomes pairs No.4 and 6 include satellite. Also according to the results of this research, A. staminum species is diploid, with 16 chromosomes (2n=2x=16), with sizes between 6.807–10.456 μm. A. iranicum species, is tetraploid and its karyotype includes 32 chromosome (2n=4x=32), with sizes of 6.719–12.221 μm. A. leave, A. dictyoscordum and A. cardiostemon are diploid with 16 chromosomes. 1B chromosomes were observed for these last 2 species of East Azerbaijan populations (2n=2x=16+1B).
Reef fishes of the order Perciformes represent an interesting group for both genetic and cytogenetic studies as their evolutionary pattern, usually unclear, might range from dynamic to quite stable. A karyotype with 2n=48 acrocentric chromosomes is considered basal for this group, whereas karyotypes with other formulae are regarded as derived. Some Perciformes families present a high karyotypic diversification such as Apogonidae, although cytogenetic reports in this family along South Atlantic were absent so far. In the present work, cytogenetic analyses were carried out in Apogon americanus from Northeastern Brazil, revealing a modal diploid number of 2n=36 (12m+6sm+16st+2a; FN=70) and a remarkable presence of large metacentric pairs. The Ag-NORs were located on short arms of the 8th pair, at telomeric position, coincident with hybridization signals obtained by FISH using 18S rDNA probes. The 5S minor ribosomal genes are distributed in 2 chromosomal pairs, not syntenic to the major ribosomal subunits. Heterochromatic blocks are located mainly at pericentromeric position in most of chromosomal pairs. The early replication pattern showed longitudinal bands with both early and late replication in the heterochromatin segments, being very similar to the pattern obtained after chromosomal digestion with EcoRI restriction enzyme. The present data, coupled with previous reports in other species, suggest a karyotypic evolution mainly driven by Robertsonian fusions (Rb) and pericentric inversions. In spite of the structural rearrangements, some features in the DNA composition and specific regions, such as 5S and 18S rDNA sites, reflect symplesiomorphic karyotype traits, shared by other clades in Perciformes.
A meiotic study was performed on 21 populations of 17 Cirsium species growing in Iran. The species of C. spectabile, C. congestum, C. strigosum, C. ciliatum, C. osseticum, C. aduncum, C. haussknechtii, C. turkestanicum, C. echinus, C. obvallatum, C. libanoticum, C. alatum, C. echinus, C. obvallatum, C. libanoticum, C. hygrophilum and C. arvense had 2n=2x=34 chromosome number, while the species of C. lappaceum, C. vulgare and C. elodes showed 2n=4x=68. The chromosome numbers of C. spectabile, C. strigosum, C. haussknechtii, C. lappaceum, C. turkestanicum and C. libanoticum are new to science and a new polyploidy level (4x) has been reported for C. elodes. The ANOVA test revealed significant differences for chiasma frequency and chromosome pairing among the species studied and the Pearson coefficient of correlation determined showed significant positive correlation between intercalary chiasmata and the mean number of quadrivalents. Although diploid species and populations are expected to form only bivalents in metaphase I, quadrivalents were formed in C. arvense, C. ciliatum, C. congestum, C. echinus, C. strigosum and C. libanoticum possibly due to the occurrence of heterozygote translocations. Interestingly enough, tetraploid species of C. lappaceum did not form any quadrivalents showing diplontic behavior. The occurrence of large pollen grains (possibly 2n pollen grains) was observed along with smaller (normal) pollen grains in species and populations showing tripolar cells. Cytological characteristics may be used in species delimitation in Cirsium but may not be used in sectional delimitation of the genus.