Detailed Karyotype Analysis Research Articles

Ecotype variations in karyotypes and 2C DNA content in Drimia indica (Roxb.) Jossop: An important medicinal plant

Indian squill (Drimia indica) belonging to the family Asparagaceae is a highly medicinal herb with several therapeutic properties. Detailed karyotype analysis and 2C DNA contents were reported in twelve ecotypes of D. indica from different geographical locations in the state of Odisha, India. The diploid somatic chromosome 2n = 20 was recorded in four ecotypes ODi-16 (Kendrapada), ODi-23 (Tikarpada), ODi-24 (Daspalla), and ODi-26 (Odagaon) while tetraploid having 2n = 40 was newly reported in one ecotype from Nuagaon (Eco-ODi-06). Aneuploid chromosome number 2n = 26 was obtained in ecotypes from Similipal and Satkosia besides 2n = 32 was newly reported in ecotypes from Bitarkanika and Narasinghpur. The ecotypes ODi-22 (Nayagarh) and ODi-11 (Nilagiri) were found to be with 2n = 16 and 2n = 22 respectively. The 2C DNA content analysis showed a 2.19-fold increase which is confirmed by an increase in the number and chromosome length of ecotypes. The 2C DNA values were found highest at 36.26 p.g. (2n = 40) in Eco-ODi-06 (Nuagaon) and lowest 16.54 p.g. (2n = 16) in Eco-ODi-22 of Nayagarh that corresponds with ploidy and genome size. The asymmetry in the karyotypes showed non-significant clusters among the ecotypes except ecotypes ODi-26 (Odagaon) and ODi-2a (Bhitarkanika) which are most asymmetric having advanced karyotypic features as compared to the ecotypes ODi-01, ODi-08 and ODi-22 having symmetric karyotypes. The chromosome characteristics along with genome size analysis of D. indica can be very useful in establishing genome-specific cytotypes which can be used for breeding programs for crop improvement. Furthermore, enhancement of therapeutic phytoconstituents and cyto-taxonomic identification from adulterants and confirmation of allopolyploidy or autopolyploidy through genomic in situ hybridization could unravel the potential of this plant in relation to secondary metabolite production.

Karyomorphological Analysis in Strychnos dalzellii C. B. Cl. and Strychnos minor Dennst. - The Indigenous Climbers of India

Karyomorphological characterizations are important for accounting floristic geography, origin, evolution, speciation and helps in the documentation of these species genetically. In the present study, a detailed karyotype analysis has been developed for Strychnos dalzellii C. B. Cl. and Strychnos minor Dennst. - the two prosperously growing, ethnomedicinally well-known climbers of the family Loganiaceae. The chromosome number of S. dalzellii and S. minor was found to be 2n=38 and 2n=40 and the karyotypic formula is A12 + B16 + C10 = 2n = 38 and A6+ B14 + C20 = 2n= 40 is respectively. On the basis of position of centromere, the formula can be written as, m34 + sm3 + st1 = 2n= 38 and m38+ sm2 = 2n=40 for Strychnos dalzellii C. B. Cl. and Strychnos minor Dennst. respectively. This pool of genetic variation needs to be measured and recorded to increase the awareness of the importance in adopting conservation and sustainable utilization.

Degenerated, Undifferentiated, Rearranged, Lost: High Variability of Sex Chromosomes in Geometridae (Lepidoptera) Identified by Sex Chromatin.

Sex chromatin is a conspicuous body that occurs in polyploid nuclei of most lepidopteran females and consists of numerous copies of the W sex chromosome. It is also a cytogenetic tool used to rapidly assess the W chromosome presence in Lepidoptera. However, certain chromosomal features could disrupt the formation of sex chromatin and lead to the false conclusion that the W chromosome is absent in the respective species. Here we tested the sex chromatin presence in 50 species of Geometridae. In eight selected species with either missing, atypical, or normal sex chromatin patterns, we performed a detailed karyotype analysis by means of comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The results showed a high diversity of W chromosomes and clarified the reasons for atypical sex chromatin, including the absence or poor differentiation of W, rearrangements leading to the neo-W emergence, possible association with the nucleolus, and the existence of multiple W chromosomes. In two species, we detected intraspecific variability in the sex chromatin status and sex chromosome constitution. We show that the sex chromatin is not a sufficient marker of the W chromosome presence, but it may be an excellent tool to pinpoint species with atypical sex chromosomes.

Karyotype Analysis of Populations in Five Satureja Species from Iran

A karyological study of five taxa (15 populations) of the genus Satureja L. from different geographic origins is presented. The haploid levels were different among species (n= 12 and 15). The work deals with chromosome number and morphometry. We found two of the usual basic chromosome numbers in this study for satureja species, x=12 and x=15. All populations were diploid and were located in 1B or 2B Stebbins classes. The karyotypic results showed the diversity among the species as mostly displayed median region (m) and submedian region (sm) and the chromosome lengths were determined between 0.60 µm in S. sahendica (1041) to 2.27 µm in S. macrantha (3). Detailed karyotype analysis allows us to group the different populations and determine the relationships among them. It also pointed out the possibility of inter and intra-species cross to improve plants.

Karyotype Variation in Eight Cultivars of Indian Dessert Banana (Musa acuminata L.) of Section Eumusa From Odisha, India

Banana (Musa spp.) cultivars especially dessert banana are important cash crop with high market demand all over the world as an integral part of the diet. The need for assessment of cytogenetic characters in Musa cultivars is inevitable as out of thousands of cultivars, cytogenetic characterization of most of them remains unresolved due to difficulties like small chromosome size, diversity in ploidy levels and high cultivar diversity which behave differently to standardized cytogenetic protocols. In this report, somatic chromosome number, detailed karyotype analysis including total chromosome length, volume, form percentage, Interphase Nuclear Volume (INV) were accessed on eight dessert type of Musa accessions from different places of Odisha. All the cultivars studied were found triploid (2n = 33) with a basic chromosome number of x=11. The karyotype formulae were assigned to each cultivar by grouping the chromosome according to their shared characteristics. The total chromosome length ranged from 54.95 µm in cv. Robusta to 81.5 µm in cv. Kathia with symmetric karyotype in all the studied cultivar. Karyotype formula revealed structural alteration of chromosome with Total Form percentage (TF%) variation from 35.65% in cv. Amritapani to 41.68% in cv. Patakpura that confirms more number of nearly median constricted chromosome as compared to sub-median chromosome. The total chromosome volume recorded from 10.78 µm3 in cv. Robusta to 15.99 µm3 in cv. Khatia and the INV varied from 1336.44 µm3 in cv. Dwarf Cavendish to 2048.37 µm3 in cv. Patakpura. The recorded structural variation might be due to differential genome specific condensation of chromosome. Chromosome length and volume found statistically significant among the cultivars.

Karyomorphological study of Houttuynia cordata Thunb.: an ethnobotanical species of Manipuri community of Tripura, India

Houttuynia cordata Thunb. (Saururaceae), has the chromosome number of 2n = 112 with karyotype formula A2+B98+C12. The size of the chromosomal complement was found to range from 1.52 µm to 3.00 µm with one pair of chromosomes bearing secondary constrictions. The detailed karyotype analysis revealed that chromosomes fall under the Stebbins category of 1A, which indicating slightly asymmetric nature of chromosome. The chromosome tally and conformity of the karyotype in the present study corroborated as a new cytotype being adapted in this area, the north-eastern region of India.

Cytogenetic Investigations in Emballonuroidea. III. Extensive Chromosomal Reorganization Characterizes the Karyotype of Saccopteryx bilineata

The only representatives of Emballonuridae in the Neotropics are Diclidurini from the subfamily Emballonurinae. In this tribe, karyotype comparison based on G-banding patterns has revealed extensive chromosomal divergence. Here, we present for the first time a detailed karyotype analysis of a Diclidurini species, Saccopteryx bilineata (SBI), by G-banding and cross-species fluorescence in-situ hybridization (FISH) with Myotis myotis (Vespertilionidae) painting probes. The 25 evolutionarily conserved units (ECUs) ancestral to all Chiroptera were found as 37 segments on the 2n = 26 SBI karyotype. Comparison with the karyotype of another Emballonuridae (Emballonura monticola) from South-East Asia revealed a single common derived segment combination, MMY3+MMY22i, pointing to a fast karyotype evolution in Emballonurinae.

Karyotypic phylogeny and polyploidy variations of Paronychia (Caryophyllaceae) taxa in Turkey

Chromosomal data can provide very valuable information about karyotypic phylogeny and speciation. This is the first study on karyotype phylogeny and polyploidy variations of the genus Paronychia. In this context, the results are these: 1 in 14 taxa, the first report on chromosomes numbers; 2 in 2 taxa, equal chromosome numbers as in the previous report; 3 in all taxa, the first report of detailed karyotype analyses; 4 karyotype asymmetry data and generally symmetrical karyotypes; 5 karyotypic variations by mechanisms of dysploidy and polyploidy; and 6 phylogenetic relationships in Paronychia. The data indicate that Anatolia is an important area for the distribution of Paronychia. In light of all data, karyotype evolution is briefly summarized. The ancestral karyotype was x = 9 millions of years ago . The karyotypes x = 8 and x = 7 were then shaped by dysploidy. The rate of polyploidization then significantly increased in the genus. However, data should be supported by molecular analysis. In addition, the chromosome numbers of 8 species of Turkish Paronychia is still unknown. The determination of the karyological data of all species is very important to understand karyotype evolution and chromosomal phylogeny in Paronychia.

Karyotype analysis of Solanum torvum Sw. - an ethnobotanical Solanaceous species of Tripura, North East India

Solanum torvum Sw. is a wild Solanaceous plant species, commonly used by the indigenous people of Tripura. Cytological study of the species was carried out to determine the somatic chromosome number and to construct the karyotype formula. The detailed karyomorphological analysis revealed 2n=24 somatic chromosomes having haploid number n=12. The size of chromosomal complement was found to range from 2.14±0.21 to 4.02±0.26 µm with a pair of chromosomes bearing secondary constrictions. Strictly median primary constriction was recorded in two pairs of chromosomes. In general, karyotype formula was found to be A2B4C18. The detailed karyotype analysis revealed that chromosomes are generally small in size and fall under the Stebbins category of “2A” indicating symmetrical nature of the karyotype. The present study could be utilised in understanding the cytogenetic nature of the species and for future crop improvement programme.

Karyotypic studies in eight populations of Zhumeria majdae Rech. f. & Wendelbo from Iran

AbstractThe karyotype asymmetry/symmetry of a taxon (eight populations) from different geographic sites of Zhumeria genus is presented. The ploidy level between and within populations was 4x. According to intra-chromosomal asymmetry, population Z2 had the most symmetrical karyotype and population Z7 had the most asymmetrical evolutionary karyotype among the populations. In terms of the Stebbins system, the karyotype of populations can be classified in 1A, 2A and 2B classes. The results of analysis of variance revealed significant differences between the populations based on nine karyotypic traits (p < 0.05 and p < 0.01). Cluster analysis showed that the populations of Zhumeria majdae have been grouped in separate clusters. The results seemed to provide enough genetic evidence to identify different populations and useful data to clarify the interspecific relationships. Detailed karyotype analysis allows us to group the different populations and to postulate relationships among them.

Study on the Cytotaxonomy of Some Species of the Genus Festuca (Poaceae)

The karyological study of four species (11 populations) of the genus Festuca L. from different geographic origins is presented. Basic chromosome number in all populations was x = 7. A large variety of ploidy levels ranging from diploids to octoploids was obtained in different species and populations. Chromosomes of all populations were mostly metacentric (m) and sub-metacentric (sm). According to intrachromosomal asymmetry, F. rubra (8308) and F. pratensis (9623) had the most asymmetrical karyotypes and F. ovina (2127 and 2357) had the most symmetrical karyotype among all populations. While based on interchromosomal asymmetry, among diploid populations, F. pratensis (4363) and among hexaploid populations, F. arundinacea (3996) had the most asymmetrical karyotype. The results of analysis of variance revealed significant differences between the populations based on all karyotypic characteristics (p < 5%) except for A2. The results of cluster analysis showed that populations have been grouped in three clusters. Detailed karyotype analysis allows us to group different populations and interpret their relationships.

Karyotype Analysis and 4C Nuclear DNA Estimation in Different Cultivars of &lt;i&gt;Clitoria ternatea&lt;/i&gt; L.

The present article has reported a detailed karyotype analysis and 4C nuclear DNA estimation in different cultivars and populations of Clitoria ternatea L. of Fabaceae. This plant, widely distributed in tropical regions in India, is a climber and is an economically important medicinal plant. The karyotype study has revealed a constancy in the diploid somatic chromosome number (2n=16) in all these cultivars and populations. However, the nature and number of nucleolar chromosomes varied. The centromeric chromosomes were either metacentric or sub-metacentric in all these cultivars. The total chromosome length and volume differed among these cultivars and populations having the same somatic chromosome number. The differential condensation of chromosomes and the association of variable amounts of proteins in chromosome composition might have been responsible for such differences. In situ cytophotometric studies revealed an intermediate genome size in this species. This is the first report on the detailed karyotype and genome size of cultivars of Clitoria ternatea L.

Prenatal molecular cytogenetic analysis of a mild dysmorphic fetus with a huge unbalance karyotype involving partial 9p deletion and partial 18q duplication

Partial 9p deletion syndrome and partial 18q duplication syndrome each have distinct clinical features. We describe the prenatal molecular cytogenetic analysis of a de novo unbalanced karyotype with deletion of 9p23-pter and duplication of 18q12.2-qter in a mild dysmorphic female fetus. Fetal ultrasonography was performed and detailed karyotype analyses were conducted using a combination of G-banding, SKY analysis and FISH with chromosome arm specific sub-telomeric DNA probes and chromosomal region specific BAC clone probes. The fetal sonography and fetal echocardiography at 17 weeks’ gestation did not reveal any anomaly while the fetus had a large unbalance karyotype of 46,XX,der(9)t(9;18) (p23;q12.2) de novo. Its external phenotype at 21 weeks appeared to have some mild dysmorphic features including hypertelorism, low-set ears, micrognathia/retrognathia, clenched hands and rocker bottom feet. These dysmorphic features are seen in the Edward syndrome but with milder degrees.

Allopatric divergence in Astyanax aff. fasciatus Cuvier, 1819 (Characidae, Incertae sedis) inferred from DNA mapping and chromosomes

The fish genus Astyanax represents a suitable model to test the role of chromosomal changes in population structure and speciation. Therefore, we performed a detailed karyotypic analysis of Astyanax aff. fasciatus from rivers in South America with incorporation of multivariate analyses as an innovate approach to infer chromosomal diversity. Ten populations of Astyanax aff. fasciatus from distinct coastal basins in northeastern Brazil were cytogenetically analyzed using Giemsa, Ag-NOR and fluorochrome staining, C-banding, mapping of rDNA and a genus-specific satellite DNA (As51). A multivariate analysis of chromosomal data was carried out to provide a consensus dendrogram of intraspecifical relationships. In spite of sharing the same diploid number, similar C-banding patterns, the populations varied in karyotype formulae and location of 18S and 5S rDNA cistrons, GC-rich segments, and As51 satDNA. The multivariate analysis showed CG-specific markers are poorly correlated to 18S rDNA. The dendrogram revealed that intraspecifical chromosomal differences are not explained by geographic distance. Instead, this variation seems to be related to the biogeographic history of northeastern Brazil and/or to the presence of unique evolutionary units under incipient speciation. Finally, we strongly recommend the incorporation of statistical analysis in cytogenetic studies of fish, particularly in groups of remarkable intraspecifical diversity as Astyanax. Such studies are useful because they provide a reliable interpretation of chromosomal variation.

Genotypic variations of ten Indian cultivars ofColocasia esculentavar.antiquoromSchott. evident by chromosomal and RAPD markers

Detailed karyotype, genome size and RAPD marker analysis were employed to assess genetic diversity in Taro (Colocasia esculenta var antiquorom Schott.). Karyotype analysis revealed genotype specific chromosomal characteristics and structural alterations in chromosome with variations of ploidy from 2n = 2x = 28 (cv. Mothan, cv. Muktakeshi, cv. Sree Kiran, cv. Sree Pallavi, cv. Sunajhili) to 3n = 3x = 42 (cv. Banky, cv. DP-25, cv. Duradin, cv. H-3, cv. Telia) in the genome. Highly significant variations in the genomic length, volume and total form (TF) % were noted at variety level. Total genomic chromosome length varied from 46.96μm in cv. Sree Kiran to 100.49μm in cv. Duradin. Total genomic chromosome volume varied from 18.22μm3 in cv. Sunajhili to 38.22μm3 in cv. Duradin. Total form percentage was varied from 24.94% in cv. Sree Kiran to 39.04% in cv. H-3 confirming near metacentric to metacentric chromosomes in the karyotype. Significant variations in the 4C DNA content noted among the cultivars that ranged from 7.24 pg in cv. Sree Kiran to 18.24 pg in cv. Duradin; accordingly, genome size varied from ~7095 to 17875 Mbp. High genome size in all the triplod varieties with 3x = 42 chromosomes could be due to the presence of extra set of chromosomes in the genome or high amount of repetitive DNA. The variation in the genome size at the variety level might be attributed to loss or addition of highly repetitive sequences in the genome. Amplification of genomic DNA in 10 genotypes using Operon primers yielded 230 amplified DNA fragments, ranging in size from 200 to 2500bp out of which 79 bands were polymorphic. A total of 8 unique RAPD bands were observed among 10 taro genotypes that revealed primer wise polymorphism ranged from 16.66 to 47.36% with an average polymorphic percentage of 34.34%. Whereas, among the cultivars the polymorphic percentage varied from 3.70% between cv. DR-25 & cv. Duradin and cv. Telia & cv. H-3 to 41.94% between cv. Mothan & cv. Muktakeshi. Genetic similarity based on Jaccard’s coefficient varied from 0.54 to 0.96, indicating wide genetic variability among the varieties based on RAPD markers. Similarity measures and cluster analysis generally reflected the expected trends in relationships of diploid and triplod taro varieties. Dendrogram obtained from the genetic distances among the varieties could be useful for breeders to choose the diverse parents for breeding programme aimed at varietal improvement.

Cytogenetic Studies in Some Species of Medicago L. in Iran

A karyological study using the Image Analysis System was conducted of eight taxa of the genus Medicago L. namely M. radiata L., M. intertexta (L.) Mill. M. orbicularis (L.) Bart. , M. laciniata (L.) Mill., M. coronate (L.) bartal, M. rigidula (L.) All., M. polymorpha L.and M. scutellata (L.) Mill. used as forage plants from different geographic origins of Fars province from Iran. We found the two usual basic chromosome numbers in the genus, x=7 and x=8. In the group with x=7, two diploid (2n=14), one tetraploid (2n=28) species and in the group with x=8, five diploid (2n=16) species were found. Detailed karyotype analysis allows us to group the different species and to postulate relationships among them.

Karyotype analysis of ten draught resistant cultivars of Indian taro - Colocasia esculenta cv. antiquorom Schott

Somatic chromosome number, detailed karyotype and genome size analysis were made to assess genetic diversity in ten drought resistant cultivars of Indian Taro (Colocasia esculenta var antiquorom Schott.). Karyotype analysis revealed genotype specific chromosomal characteristics and structural alterations in chromosomes of the genome, with variations of ploidy from 2n = 2 × = 28 (cv. Mothan, cv. Muktakeshi, cv. Sree Kiran, cv. Sree Pallavi, cv. Sunajhili) to 3n = 3 × = 42 (cv. Banky, cv. DP-25, cv. Duradin, cv. H-3, cv. Telia). Highly significant variations in the genomic length, volume and total form (TF) % were noted at variety level. Total genomic chromosome length varied from 46.96 μm in cv. Sree Kiran to 100.49 μm in cv. Duradin. Total genomic chromosome volume varied from 18.22 μm3 in cv. Sunajhili to 38.22 μm3 in cv. Duradin. Total form percentage was varied from 24.94 % in cv. Sree Kiran to 39.04 % in cv. H-3 confirming mostly of near metacentric to metacentric chromosomes in the karyotype. Significant variations in the 4C DNA content noted among the cultivars that ranged from 7.24 pg in cv. Sree Kiran to 18.24 pg in cv. Duradin; accordingly, genome size varied from ~7,095 to 17,875 Mbp. High genome size in all the triplod varieties with 3 x = 42 chromosomes could be due to the presence of extra set of chromosomes in the genome or high amount of repetitive DNA. The variation in the genome size at the cultivar level may be attributed to loss or addition of highly repetitive sequences in the genome. Detailed chromosomal analysis of ten drought resistant cultivars could help breeders to choose the diverse parents for breeding programme along with high yielding drought susceptible varieties for future crop improvement programme.

Cytogenetic studies of two Dracocephalum (Lamiaceae) species and populations in Iran

A karyological study of two taxa (11 populations) of the genus Dracocephalum L. from different geographic origins is presented. We found the two usual basic chromosome numbers in the genus. Basic chromosome numbers in all of the populations of Dracocephalum moldavica L. were x= 5 (2n=2x=10) and in Deracocephalum kotschyi Boiss. were x= 10 (2n=2x=20). Chromosomes in all of populations of D. moldavica and D. kotschyi were located in 1A and 1B classes respectively. The chromosome lengths were determined between 1.88-2.16µm in D. moldavica and 1.37-1.63µm in D. kotschyi. Detailed karyotype analysis allows us to group the different populations and to postulate relationships among them.

Karyotypic Studies of five Paeonia ludlowii populations from China

Abstract karyotype of five Paeonia ludlowii populations from Tibet were analyzed in this study. P. ludlowii was indicated to be a more primitive taxon. Each population possessed the same chromosome number as 2n = 10, x = 5, and the karyotypic formulae as 2n = 8m + 2st. Population JZ possessed the most asymmetrical and evolutionary karyotype based on intrachromosomal asymmetry with the highest A1 and lowest TF; According to the interchromosomal asymmetry with the value of A2 and DRL, population CM was most asymmetrical. Detailed karyotype analysis showed that the length of SA was the main factor to group the different populations and to investigate the relationships among them. It suggested that when in a relatively narrow area, the karyomorphological variance of P. ludlowii mainly contribute to the hereditary property.

Karyology of nineTrifoliumL. taxa from Turkey

This research comprises a karyologic study of the nine taxa of Trifolium from Turkey. From the Trifolium L. section, Trifolium striatum L. and T. leucanthum Bieb. chromosome numbers were 2n = 14, T. echinatum Bieb. was 2n = 16 and T. phleoides Pourr. ex Willd was 2n = 12. From the Vesicaria Crantz. section, T. resupinatum L. var. resupinatum, T. clusii Godr. and Gren., and T. tomentosum L. all had chromosome numbers of 2n = 16. Chromosome numbers of T. retusum, L. from section Lotoidea, Crantz. and T. glanduliferum Boiss. var. glanduliferum from section Paramesus (C. Presl) Gris. were all found to be 2n = 16. Seven of the 9 taxa contained all pairs of chromosomes and were metacentric; the remaining taxa included 7 were metacentric and only one pair was submetacentric. One pair of satellites was found in T. phleoides. This study reports detailed karyotype analyses from Turkey for the first time in Trifolium.