Giemsa C-banding Technique Research Articles

Rye chromosome composition and seed characters in hexaploid triticale (X Triticosecale WITTMACK)

The individual characteristic features of chromosomes in Petkus rye (diploid) and 82 hexaploid triticale accessions were assessed to identify the replaced rye chromosome pair(s) in triticale and its effect on kernel characters. GiemsaC-banding technique was used for the study. Results revealed that 24 hexaploid triticales showed full complement of rye chromosome, 34 had replacement of one pair and 24 had replacement of two pairs of rye chromosomes. Triticale strains with 2R/2D and 4R/4D substitutions had higher and medium seed set, respectively. Seed set was considerably high when both with 2R/2D and 4R/4D substitution occured together.

A C-banded karyotype of mitotic chromosomes in diploid purple coneflower (Echinacea purpurea L.).

BackgroundAneuploid ermpglasm is an important resource for genetic studies and identification of individual chromosomes in the cells of the aneuploid is an important step. The karyotype has already been established for purple coneflower (Echinacea purpurea L.), but due to the high similarity in the morphology of several pairs of chromosomes in this species, it cannot be used to identify individual chromosomes in its own complement. The objectives of this study are to develop and evaluate the Giemsa C-banding technique for the purpose of identifying the individual chromosomes in Echinacea purpurea.ResultsThe established karyotype with C-bands showed that all the 11 pairs of chromosomes possessed centromeric bands. Telomeric bands appeared most frequently in almost all the chromosomes with only two exceptions, the short arm of the chromosome 9 and the long arm of the chromosome 10. Intercalary bands were found mainly in the long arm of some chromosomes with only two exceptions, the chromosomes 1 and 2 that had intercalary bands on both arms. The chromosome 4 was the only chromosome where intercalary bands were absent.ConclusionsChromosomes in E. purpurea could be stained with Giemsa to bear C-bands. By classifying the chromosomes into groups and judging the C-bands, each chromosome could be identified. The methods established in this study might be used for the identification of chromosome constitution in aneuploid E. purpurea created in a breeding program.

Identification of rye chromosome substitutions in Triticale and its relation with kernel characters and seed setting through Giemsa C-banding technique

To study the individual characteristic features of chromosomes in the three varieties of diploid rye and the 54 hexaploid triticale strains and also to identify the replaced rye chromosome pair or pairs in triticale and the relation of rye chromosomal substitutions with kernel characters. The present study was conducted using Giemsa C-banding technique. The results showed rye chromosome 2R was replaced in large number of cases followed by 4R/7R, 5R and 2R+5R. Triticale strains with 4R/7R substitution exhibited low degree of shriveling in grains with higher values for test weight, 100-grain weight and volume of water displaced by 100-grains whereas 4R/7R substitution along with another substitution for 2R or 5R or 6R showed medium shriveling and strains with substitutions either for 2R or 3R or 5R or 7R/4R exhibited high degree of shriveling and a cumulative effect was observed when two of these substitutions were presented together in one triticale. Triticale strains with 2R/2D substitution had higher seed set and it was medium in case of 4R/4D. But when both 2R/2D and 4R/4D substitution occur together the seed set was considerably high and was low when 3R and 5R substituted alone or in combination. It has shown evidence in the present study about the role of individual R/D substitutions on the quality of seeds it is necessary to introduce those substitutions which are of agronomic importance to the breeders.

Heterochromatin polymorphism in the rye karyotype as detected by the giemsa C-banding technique.

Identification of the individual chromosomes in the rye variety “Stalrag” and in two inbred lines of rye was carried out by means of the Giemsa C-banding technique and related to earlier investigations. Heterochromatin polymorphism occurs between plants and between homologues. Possible explanations of the variability of the banding pattern are discussed. Grouping of heterochromatic regions at interphase and fused telomeres at prophase were observed and discussed.

C-bands and ploidy level of Hippophaë rhamnoides

The Giemsa C-banding technique was found to be a useful tool in the karyotype analysis of Hippophae. Three strains of H. rhamnoides L. were studied, two representing ssp. rhamnoides, one ssp. mongolica Rousi. A C-banded idiogram of one of the ssp. rhamnoides strains is presented. The C-bands are generally located on both sides of the centromere, but their sizes and numbers vary between chromosomes. Certain small differences in the banding pattern could be seen between the strains. The C-banded karyotype shows clearly that 2n=24 cannot be an autopolyploid number as has been repeatedly assumed. In all probability, it represents the diploid level.

The rye genome in wheat breeding

Merker, A. 1984. The rye genome in wheat breeding. —Hereditas 100: 183–191. Lund, Sweden. ISSN 0018–0661. Received June 10, 1983 Five different BC1F3-populations from the cross (hexaploid triticale × bread wheat) bread wheat× were cytologically analysed for the presence of rye chromatin by means of a Giemsa C-banding technique. The populations contained from 13 to 30 per cent plants with detectable rye transfers. Different rye chromosomes appeared in different frequencies. IR being the most frequent and 7R the least. 5R and 7R appeared only in monosomic dose, the others in disomic also. The populations had high frequencies of aneupioids. Of the plants with rye transfers. 60 per cent were aneuploid and. of those without, 47 per cent were aneuploid. Average fertility for the group with rye transfers was lower than for the group without. Fertile disomic substitution lines with the rye chromosomes IR. 2R. 3R and 6R have been isolated from the material. The results are discussed in relation to the extension of the gene pool of bread wheat and in relation to wheat breeding.

Constitutive heterochromatin DNA polymorphisms in diploid Medicago sativa ssp. falcata.

A Giemsa C-banding technique was used to study the amount and location of constitutive heterochromatin in diploid (2n = 2x = 16) Medicago sativa ssp. falcata (L.) Arcangeli. Most accessions had the standard C-banding pattern with centromeric bands on all the chromosomes and a prominent heterochromatic band at the nucleolar organizer regions (NOR) of the satellited (SAT) chromosomes. However, we observed in various accessions that constitutive heterochromatic C-bands can exist at the telomeric ends of all the chromosomes. Interstitial bands occurred on the short arms of all chromosomes except for chromosome 3 and on the long arms of chromosomes 1, 2, 3, and 6, only. Rearranged chromosomes such as isochromosomes have been observed for the short arms of chromosomes 2 and 6. This is the first report on the existence of C-banding polymorphisms and the detection of putative isochromsomes in the chromosomes of diploid ssp. falcata which could have contributed to the variation observed in cultivated alfalfa.

Giemsa C-banded Karyotypes of Eight Species of AlstroemeriaL. and Some of Their Hybrids

Karyotype analysis of Alstroemeria angustifoliassp. angustifolia, A. aurea, A. inodora, A. ligtuspp. ligtu, A. magnificassp. magnifica, A. pelegrina, A. philippiiand A. psittacinausing Feulgen-staining and Giemsa C-banding techniques revealed for each species a characteristic chromosome morphology and C-banding pattern. These characteristics could be used to identify many individual chromosomes in diploid interspecific hybrids. Besides interspecific variation, some degree of intraspecific variation in C-banding pattern was observed within A. angustifoliassp. angustifolia, A. aurea, A. ligtussp. ligtu, A. magnificassp. magnificaand A. philippii. All species had large chromosomes (2 n=2 x=16) and asymmetric karyotypes. In many species the short arms of the acrocentric chromosomes were darkly stained upon Giemsa C-banding. These telomeric bands seemed satellites. B-chromosomes were observed in one species, A. angustifoliassp. angustifolia. A variable number of large intercalary and telomeric C-bands was present in the Chilean species, whereas the Brazilian species showed only small C-bands. The differences in karyotypes suggest an early separation of the Chilean and Brazilian species, after which speciation followed different evolutionary pathways. In Alstroemeriathe Giemsa C-banding technique can be valuable to plant taxonomists for unravelling species relationships.

Chromosome Identification in Potato Trisomics(2n=2x+1=25) by Conventional Staining, Giemsa C-banding and Non-radioactive in situ Hybridization.

Identification of the potato chromosomes 1 (the longest one), 2 (the carrier of the nucleolar organizer, NOR) and 12 (the shortest one) is possible at mitosis using a combined Feulgen-haematoxylin staining or a Giemsa C-banding technique. In two aneuploids containing 27 chromosomes, three specimens of chromosome 1 were found through conventional staining. Variation of the length of the NORs and the size of the satellite of homologues or homoeologues of chromosome 2 was observed in various cytotypes. Pachytene analysis identified trisomics of chromosome 2 of interspecific origin, involving S. tuberosum L. ssp. tuberosum Hawkes and S. phureja Juz. et Buk., but only two specimens of chromosome 2 could be identified using the Giemsa C-banding technique. However, in six different interspecific chromosome 2-trisomics, three chromosomes per cell were found to show a hybridization signal by non-radioactive in situ hybridization with heterologous rDNA from pea. The high polymorphism of chromosomes observed after Giemsa C-banding made it impossible to bring the identity of the mitotic chromosomes in accordance with the results from pachytene identification in cells containing one triplicate chromosome.

Characterization of wheat/Aegilops ventricosa introgression and addition lines with respect to the Mv genome

Stable wheat-Aegilops introgression lines with 42 chromosomes (H-93), derived by repeated selfing from a cross (Triticum turgidum x Aegilops ventricosa) x T. aestivum, have been characterized using the following DNA probes and isozyme markers: (1) single or low-copy DNA fragments from Ae. ventricosa; (2) known cDNA probes corresponding to α1-thionin, monomeric α-amylase inhibitor, the CM3 subunit of tetrameric α-amylase inhibitor, and sucrose synthase from wheat; (3) anonymous cDNA probes from wheat that have been mapped by Sharp et al. (1989); (4) isozyme markers corresponding to aconitase, shikimate dehydrogenase, adenylate kinase, and endopeptidase. Meiotic metaphases of appropriate hybrids involving selected H-93 lines have been investigated by the Giemsa C-banding technique. The substitution of whole chromosomes [(5A) 5M(v); (4D) 4M(v); (5D) 5M(v); (7D) 7M(v)] and chromosomal segments (1M(v); 3M(v); 5M(v); 7M(v)) from the M(v) genome of Aegilops ventricosa has been demonstrated. The distribution of selected markers among putative wheat-Ae. ventricosa addition lines has also been investigated. The 7M(v) addition has been characterized for the first time, while the identity of the previously reported 5M(v) and 6M(v) additions has been confirmed.

Identification of C-banded chromosomes in meiosis and the analysis of nucleolar activity in Avena byzantina C. Koch cv ‘Kanota’

The Giemsa C-banding technique was used to identify individual meiotic and somatic chromosomes in 21 monosomic lines of Avena byzantina C. Koch cv 'Kanota' (genome designation AACCDD). The hexaploid complement is composed of three sets of seven chromosome pairs. The heterochromatin in the putative diploid progenitors is located at the telomeres (genome A), at the centromeric and interstitial regions (genome C), or more evenly spread throughout the set (genome D). Comparisons based on C-banding between A. byzantina and its diploid progenitor species allowed us to allocate individual chromosomes into specific genomes. The C-banding technique may be useful for interspecific chromosome pairing analyses. Nucleolar activity and competition were studied using a silver-staining procedure. Only three chromosome pairs showed nucleolar organizer regions, thus indicating that nucleolar competition occurs naturally in hexaploid oats.

C-bands and chiasma distribution in Scilla siberica (Hyacinthaceae)

The distribution of chiasmata and their relationship to heterochromatic segments in Scilla siberica (Hyacinthaceae) have been analyzed in pollen mother cell meiosis by means of a Giemsa C-banding technique. All chromosomes could be identified in the meiotic cells. C-bands have a clear effect on chiasma distribution. Regions adjacent to intercalary homomorphic C-bands showed higher chiasma frequencies than other euchromatic regions. Chiasma distribution in bivalents of chromosome variants without these intercalary C-bands is different from those with C-bands. Strongly heterozygous C-blocks lead to a pronounced reduction of chiasma frequency in their vicinity. Mechanical clues for this are found in pachytene pairing behaviour of heterozygous C-bands, which also indicates that euchromatin is constant and C-bands are variable and additional segments. Within one anther, equational separations of C-band heteromorphisms were less than expected from corresponding metaphase I bonds, presumably because of a lower chiasma frequency in early meiotic cells. Heteromorphic intercalary C-bands show that chiasmata do not terminalize. Only at the onset of anaphase I does chiasma resolution result in transitory configurations reminiscent of terminalization.Key words: Scilla siberica, C-bands, meiotic recombination.

Differential meiotic behaviour of diploid and tetraploid cells in a partially asynaptic mutant

A partially asynaptic individual of the grasshopperEuchorthippus pulvinatus (2n ♂ = 16 + X) was analysed at meiosis, using a Giemsa C-banding technique. Long chromosomes formed univalents less frequently than did medium and short ones. Homologues which succeeded in forming bivalents showed reduced chiasma frequency, the long chromosomes being affected by most. Changes in chiasma distribution were also observed. The presence of univalents at metaphase I seems to affect the function of the spindle, since most cells at the second division were unreduced. Cytokinesis was also subsequently suppressed in a great number of these products of restitution, resulting in the formation of diploid and tetraploid spermatids. Fifteen tetraploid metaphase I cells were also found in which pairing level and chiasma frequency were almost twice the average value in normal diploid individuals. The nature of this mutant is discussed.

Heterozygous Heterochromatin in Giemsa C-Banded Chromosomes ofClogmia Albipunctata(Telmatoscopus Albipunctatus) (Diptera: Psychodidae)

SUMMARYThe mitotic and meiotic chromosomes of the moth fly Cloynia albipunctata were analyzed using the Giemsa C-banding technique. Heterozygous centrometric bands were observed in four pairs of chromosomes, two of which seem to be exclusive of the male sex, showing the same heterozygous condition at the male meiosis. They are probably carrying the sex determining factors in a complex system of sex chromosome determination. This system is different from the one found in the polytene chromosomes of a Brazilian strain of the same species both in type and in location of the sex determining factors.

Partial asynapsis involving specific chromosomes in intervarietal hybrids of Triticum aestivum L.

Metaphase I chromosome association of the monosomic F1 and the backcross progenies made to develop a monosomic line in the Spanish common wheat Pane-247 was analyzed using a Giemsa C-banding technique. This permits the unequivocal identification of nine meiotic chromosomes (4A, 7A and the seven chromosomes of the B genome). The average frequencies of pairing per arm and of univalents for these nine pairs per arm and of univalents for these nine pairs indicate a difference between arms. The F1 showed asynapsis with univalents in 18.5 per cent of PMC's in intervarietal hybrids. This mainly involved chromosomes 4A, 1B and 6B which also have the largest amount of constitutive heterochromatin. The possible causes of reduced metaphase I association and its rapid decrease during backcrossing are discussed in relation to polymorphism between heterozygous homologous chromosomes.

Meiotic pairing of the amphiploid Hordeum chilense X Triticum turgidum conv. durum studied by means of Giemsa C-banding technique

The meiotic behaviour of the amphiploid Hordeum chilense X Triticum turgidum conv. durum using a C-banding staining method is studied. Nine pairs of chromosomes at metaphase-1 (4A, 7A and the seven of the B genome) were identified and the remaining wheat chromosomes (1A, 2A, 3A, 5A and 6A) and seven of the chilense (1 to 7 H (ch) chromosomes) were assigned to its particular genome. A similar mean number of univalents from parental genomes (wheat and wild barley) were found. No meiotic pairing between chilense and turgidum chromosomes was detected. Differences in the meiotic behaviour per chromosome and amongst genomes are explained on the basis of cytomorphological and heterochromatin characteristics.

The meiotic pairing of nine wheat chromosomes

The meiotic identification of nine pairs of chromosomes at metaphase I of meiosis of Triticum aestivum (B genome, 4A and 7A) has been achieved using a Giemsa C-banding technique. As a result, the analysis of the pairing of each chromosome arm in disomic and monosomic intervarietal hybrids between 'Chinese Spring' and the Spanish cultivar 'Pané 247' could be carried out. Differences in the chiasmata frequencies per chromosome arm cannot be explained on the basis of relative arm lengths only. Possible effects of arm-to-arm heterochromatic differences on meiotic pairing are discussed.

Chromosome 1 in crested and marbled newts (Triturus)

The heteromorphic chromosomes 1 of Triturus cristatus carnifex and T. marmoratus were studied in mitotic metaphase after staining with the Giemsa C-banding technique and with the fluorochromes, DAPI (AT-specific) and mithramycin (GC-specific). They were also examined in the lampbrush form under phase-contrast before fixation and after fixation and staining with Giemsa. Chromosomes 1 of T.c. carnifex are asynaptic and achiasmatic throughout most of their long arms. They are also heteromorphic in most of their long arms for the patterns of Giemsa and fluorochrome staining and the distribution of distinctive lampbrush loops. The heteromorphic regions correspond to the regions that are asynaptic and achiasmatic. They stain more strongly with mithramycin and more weakly with DAPI than the remainder of the chromosomes, signifying that their DNA is relatively rich in GC. The patterns of staining with Giemsa and fluorochromes and the distributions of distinctive lateral loops vary from one animal to another in the same species and even in the same population. The asynaptic and achiasmatic regions of chromosomes 1 in T. marmoratus extend throughout the whole of the long arms and well beyond the heterochromatic region. Chiasmata form only in the short arm and occasionally in the short euchromatic segment at the tip of the long arms. The staining patterns of chromosomes 1 in T. marmoratus differ from those in T.c. carnifex although, like carnifex, their DNA is relatively GC-rich. The chromosomes 1 of T. marmoratus are more submetacentric than those of T.c. carnifex. In T. marmoratus chromosome 1B is about 12% shorter than 1A. There is a short paracentric inversion heterozygosity in the long arm of chromosome 1B in T. marmoratus which probably accounts for the lack of chiasmata in the euchromatin that separates the centromere from the start of the heterochromatin. In both carnifex and marmoratus, embryos that are homomorphic for chromosome 1 arrest and die at the late tailbud stage of development. The same applies to F1 hybrid embryos T.c. carnifex x T. marmoratus, and this has permitted identification of chromosomes 1A and 1B in both species. There is no correspondence between patterns of Giemsa or fluorochrome staining of the heteromorphic regions of chromosome 1 and any feature of the lampbrush chromosomes. However, the short euchromatic ends of the long arms of chromosomes 1 in both species are distinguished in the lampbrush form by a series of uniformly small loops of fine texture associated with very small chromomeres. The Giemsa C-staining patterns of both chromosomes 1A and 1B are different in each of the four subspecies of T. cristatus. T.c. karelinii stands out by having unusually large masses of Giemsa C-staining centromeric heterochromatin on all but 1 of its 12 chromosomes. A scheme is proposed for the evolution of chromosome 1 in T. cristatus and T. marmoratus, based on all available cytological and molecular data.

Giemsa C-banded karyotypes and taxonomic relationships of some North AmericanAllium species and their relationship to Old World species (Liliaceae)

The somatic karyotypes of six North AmericanAllium species and the EuropeanA. scorzonerifolium have been investigated using a Giemsa C-banding technique. All species have a chromosome number of 2n = 14. InA. scorzonerifolium and the three North American speciesA. dichlamydeum, A. fibrillum andA. unifolium C-bands are restricted to two pairs of nucleolar chromosomes. Each chromosome has a band proximal to the nucleolar constriction and a positively banded satellite. InA. acuminatum, in addition to the bands associated with the nucleolar constrictions, all chromosomes also have pericentromeric bands.A. cernuum exhibits a distinctive banding style: two chromosome pairs with bands adjacent to the nucleolar constrictions and four pairs with telomeric bands on their short arms. In the karyotype ofA. geyeri neither C-bands nor nucleolar chromosomes were found.—A comparison of the banding styles together with other cytological and morphological characters of these species with old world members ofAllium reveals:A. cernuum closely resembles species within subgenusRhizirideum, whereas the other species studies exhibit many similarities with subgenusMolium. Their sectional grouping and their relationships with Old World species are discussed.

On the interchromosomal connections in plants

Using Giemsa C-banding technique, the existence of interchromosomal connections in well spread root tip metaphase plates in a variety of plant species has been demonstrated. Various types of interchromosomal connections are observed, involving satellite, telomeres, interstitial regions and in a few cases centromeres, too. The possible role of these interchromosomal connections in establishing the homologous and non-homologous association in the somatic chromosomes and maintaining the spatial relationship of the genetic apparatus is indicated. In the majority of the cases the connections are made up of constitutive heterochromatin.