Giemsa C-banding Patterns Research Articles

Polyploidy in Muscari neglectum (Asparagaceae) by analysis of karyotype and Giemsa C-banding patterns

This study provides new karyological information on polyploid cytotypes of Muscari neglectum. Classical cytogenetic with the Feulgen technique and banding with Giemsa was used. Pentaploid, hexaploid and heptaploid levels of ploidy are here reported. The complement of the rare heptaploid cytotype consisted of 2n = 7x = 63: 49 m + 14sm chromosomes. Two heptaploid specimens with chromosome numbers 60 and 62 were also found. Karyotypes were symmetrical, with metacentric chromosomes more numerous than submetacentric. The morphometric parameters MCA and CVCL were used for the evaluation of karyotype asymmetry. For the first time, a detailed study using Giemsa C-banding is reported. The C-banding patterns included centromeric and terminal bands. In the cytotype with 62 chromosomes, the banding patterns identified the presence of a chromosome with terminal band in both arms. To explain the origin of this karyotype, we suggest that fusion occurred between a group IV chromosome and a group V chromosome. The relationship between the polyploid cytotypes of M. neglectum is discussed.

Cytogenetic identification of wheat-Psathyrostachys huashanica amphiploid × triticale progenies for English grain aphid resistance

English grain aphid (EGA, Sitobion avenae Fabricius) is an important pest in wheat (Triticum aestivum L.). To develop EGA-resistant varieties, introducing the desirable genes from related species is regarded as an efficient avenue. In this study, the F1, F2 and F3 plants derived from the cross of EGA-susceptible wheat-Psathyrostachys huashanica Keng ex Kuo amphiploid (PHW-SA, AABBDDNsNs) and EGA-resistant triticale (Zhongsi 828, AABBRR) were analyzed for EGA resistance. Consequently, PHW-SA was moderately susceptible while Zhongsi 828 and their F1 hybrids were immune, suggesting that the resistance is dominant. All the F2 plants showed high resistance or immunity over two years, indicating that EGA resistance genes are more likely carried by the rye (Secale cereale L.) chromosomes rather than the genomes A or B of Zhongsi 828. In the F3 generation, 25 of 239 lines became susceptible. Giemsa C-banding patterns revealed that these F3 lines had 38-40 chromosomes, including complete rye genome except 5R (and 2R in five lines). Genomic in situ hybridization analysis confirmed this result. During meiosis, all the chromosomes formed bivalents. Six bivalents in 20 lines and five bivalents in five lines were characterized from rye. In contrast, their F2 parental lines had 42 chromosomes (21 bivalents), containing 1R-7R of rye. No P. huashanica chromosomes were detected. Therefore, we propose that the rye chromosome 5R may be related to EGA resistance.

Karyotype Analysis and Giema C-Banding Patterns in <i>Thinopyron elongatum</i>

Giemsa C-banding patterns and karyotype of chromosomes were analyzed in the root-tip cells of diploid Thinopyron elongatum. A modified seed germinating method was developed for obtaining the C-banding patterns in diploid Thinopyron elonggatum. The results of The C-banding analysis showed the significant differences among the seven pairs of chromosomes in diploid Thinopyron elonggatum. The intensive C-bands were stained steadily on the intercalary, terminal, subcentromeric and centromeric regions of Chromosomes. We found that there are three pairs of metacentric chromosomes and four pairs of submetacentric chromosomes in diploid Thinopyron elonggatum. The karyotype formula is 2n=2x=14=6m+8sm. Present results provided a basic cytological data and will be useful for the further studies in Thinopyron elongatum.

Separate location of parental chromosomes in squashed metaphases of hybrids between Hordeum vulgare L. and four polyploid, alien species

Linde-Laursen, I. and Jensen, J. 1984. Separate location of parental chromosomes in squashed metaphases of hybrids between Hordeum vulgare L. and four polyploid, alien species. —Hereditas 100: 67–73. Lund, Sweden. ISSN 0018–0661. Received May 17, 1983 In 38 squashed, somatic metaphases of four hybrids between diploid Hordeum vulgare and two tetra-and two hexaploid alien species, each of the H. vulgare chromosomes was identifed, and differentiated from the chromosomes of the other parental species, by its Giemsa C-banding pattern. The H. vulgare chromosomes were located nearer the centre of the metaphase plate than the non-H. vulgare chromosomes. The location of the H. vulgare chromosomes in relation to each other did not deviate from randomness.

Distribution of isoenzyme markers at 37 loci in a pedigree of European spring barley

Linde-Laursen, I., Nielsen. G. and Johansen. H.B. 1987. Distribution of isoenzyme markers at 37 loci in a pedigree of European spring barley. —Hereditas 106: 241–251. Lund, Sweden. 018–0661. Received September 19, 1986 Inheritance of isoenzymes controlled by from 2 to 4 alleles at each of 17 loci was investigated in 59 related varieties or lines and one population of European 2-rowed spring barley. A further 20 isoenzyme loci showed no variation. Altogether the material spanned the last 150 years. Inheritance of alleles normally was as expected; however, in some cases allowance should be made for now lost polymorphism in parent(s). Polymorphism was more common in old than in recent varieties and in some varieties affected alleles at more than one locus. Some gene depletion had taken place during the period studied. However, a number of “new” alleles had been introduced together with, e.g., resistance genes from exotic lines. The variation present in modern European 2– rowed spring barley comprises a restricted part only of the variation present in the species. Isoenzyme patterns separated the material into 48 groups of one variety each. and 11 groups of two and one group of three normally closely related varieties or lines. The combined use of the isoenzyme loci was superior to the use of either hordeins or Giemsa C-banding patterns for the identification of lines.

Statistical evaluation of length measurements on barley chromosomes with a proposal for a new nomenclature for symbols and positions of cytological markers

In 100 cells of an intergeneric Hordeum×Psathyrostachys hybrid, statistical evaluations were performed on length measurements of barley chromosomes and chromosome arms recognized by their Giemsa C-banding patterns for reliable identification. In 10 cells, we included the results of distance measurements between cytological markers and/or C-bands. Both actual and relative chromosome lengths as well as distances between cytological markers were distributed non-normally. Logarithmically transformed lengths proved to be normally distributed and were used to establish desirable statistical properties of mean values and confidence limits. No barley chromosome could be identified by length alone. Mean values of the logarithmically transformed distances between chromosome ends, constrictions, and Giemsa C-bands were back-transformed and used to construct an idiogram. The generally used nomenclature for chromosome markers and their positions based on C- or N-banding patterns was found arbitrary and inadequate. Instead, we propose a new, more general, informative and simple system for designating chromosome arms and cytological markers. It would be used as follows: (i) one chromosome arm with a specific banding pattern is designated the ‘plus' arm and is depicted upwards in the idiogram; the other arm is designated the ’minus arm; (ii) total genome length is defined as “one GeNome” (symbolized GN); (iii) distances on the idiogram are given in milliGeNomes (mGN), i.e., thousandths of a GN; (iv) the centromere is given the position 0; and (v) cytological markers on the ‘plus' and ’minus' arms are designated by their positive and negative distances in mGN from the 0-position, respectively.

Chromosomal Constitution of Rye (Secale Cereale) - Hordeum Chilense Addition Lines

Among 153 plants derived from amphiploid H. chilense× rye backcrossed twice with rye, 62 plants, with 2n = 14, had exclusively rye chromosomes; 63 plants, with 2n = 15, were monosomic additions having an extra H. chilense chromosome; the remaining 28 plants with 2n = 16-21, had from 2 to 7 extra H. chilense chromosomes. Giemsa C-banding patterns of 23 randomly selected monosomic additions (2n = 15) identified plants with 5 of the 7 H. chilense chromosomes, viz. nos. 2 (7Hch). 3 (4Hch). 4 (2Hch), 6 (6Hch), and 7 (SHch). Nearly half the monosomic additions comprised the satellited H. chilense chromosome 6 (6Hch). The two H. chilense SAT-chromosomes 6 and 7 exerted nucleolar dominance over two rye SAT-chromosomes when present together. In contrast, one H. chilense SAT-chromosome was dominated by the two rye SAT-chromosomes in plants with monosomic additions of one or the other of the H. chilense SAT-chromosomes.

C-banded karyotypes of two Silene species with heteromorphic sex chromosomes.

Mitotic metaphase chromosomes of Silene latifolia (white campion) and Silene dioica (red campion) were studied and no substantial differences between the conventional karyotypes of these two species were detected. The classification of chromosomes into three distinct groups proposed for S. latifolia by Ciupercescu and colleagues was considered and discussed. Additionally, a new small satellite on the shorter arm of homobrachial chromosome 5 was found. Giemsa C-banded chromosomes of the two analysed species show many fixed and polymorphic heterochromatic bands, mainly distally and centromerically located. Our C-banding studies provided an opportunity to better characterize the sex chromosomes and some autosome types, and to detect differences between the two Silene karyotypes. It was shown that S. latifolia possesses a larger amount of polymorphic heterochromatin, especially of the centromeric type. The two Silene sex chromosomes are easily distinguishable not only by length or DNA amount differences but also by their Giemsa C-banding patterns. All Y chromosomes invariably show only one distally located band, and no other fixed or polymorphic bands on this chromosome were observed in either species. The X chromosomes possess two terminally located fixed bands, and some S. latifolia X chromosomes also have an extra-centric segment of variable length. The heterochromatin amount and distribution revealed by our Giemsa C-banding studies provide a clue to the problem of sex chromosome and karyotype evolution in these two closely related dioecious Silene species.

Eremium, a New Genus of the Triticeae (Poaceae) from Argentina

Based on evidence from morphology, Giemsa C-banding and N-banding patterns of the chromosomes, and sequence variation of rbcL, Elymus erianthus is transferred to a new genus, Eremium. Neither the S genome, which is found in all taxa hitherto included in Elymus, nor the H genome characteristic of Hordeum and found in all previously investigated South American Elymus, are found in Eremium erianthum, and Eremium is not included in the Elymus clade on the rbcL tree. Problems of discrimination and phylogenetic treatment of the heterogenomic genera of the Triticeae are briefly discussed.

Comparison of marker systems and construction of a core collection in a pedigree of European spring barley

Based on data in four publications describing European barley cultivars, similarities between pairs of cultivars were calculated using individual markers and combinations of markers. These markers included 19 isoenzyme patterns, Giemsa C-banding variants of each of the seven chromosomes, hordein polypeptide patterns, DDT susceptibility type, and three morphological descriptors. The rank correlation between the coefficients of parentage and marker-based similarities is low; the highest single marker correlation is with Est-1, 0.41, and the highest correlation with a combination of markers is 0.58. Giemsa C-banding patterns score rather high, as opposed to the three morphological characters that score very low. Selection of core collections using the effective-number-of-origin-lines theory is successful. The average number of types found in a core collection of cultivars of given size is always considerably larger than a random set of the same size. The core collection approaches the maximum possible number of types.

Intergeneric hybridization and C-banding patterns inHordelymus (Triticeae, Poaceae)

Crosses ofHordelymus europaeus (2n = 4x = 28) with four genera in theTriticeae were attempted. Adult hybrids were obtained in combinations withHordeum bogdanii (2x),Hordeum depressum (4x), andSecale cereale (2x). The meiotic pairing was very low in the hybrids withH. bogdanii andSecale cereale (0.12 and 0.30 chiasmata/cell, respectively), whereas high pairing (9.90 chiasmata/cell) was found in hybrids withH. depressum due to autosyndetic pairing ofH. depressum chromosomes. The chromosome complement ofHordelymus europaeus comprised 16 metacentrics, 8 submetacentrics, and 4 SAT-chromosomes. The Giemsa C-banding patterns of the chromosomes were characterized by small to minute bands at no preferential positions. It is hypothesized thatHordelymus europaeus may genomically be closest related toTaeniatherum andPsathyrostachys spp.

Chromosome banding and pairing behaviour inFestuca andVulpia (Poaceae, Pooideae)

Giemsa C-banding patterns of the grassesFestuca rubra (2n = 6x = 42),Vulpia fasciculata (2n = 4x = 28) and their wild F1 hybrid ×Festulpia hubbardii (2n = 5x = 35) show marked differences between the chromosomes of the two parents that enable unequivocal identification ofFestuca andVulpia chromosomes in the hybrid. Moreover, meiotic banding patterns reveal that both homogenetic (Festuca-Festuca andVulpia-Vulpia) and heterogenetic (Festuca-Vulpia) pairing occurs in the F1. The significance of this in relation to the formation of backcrosses to theFestuca parent and to the evolution of theFestuca polyploid complex in general is discussed.

Inter- and intraplant C-banding polymorphism in one population ofAegilops comosa subsp.comosa var.comosa (Poaceae)

The Giemsa C-banding pattern of the chromosomes of the native self-pollinatedAegilops comosa subsp.comosa var.comosa was studied. Six of the seven chromosomes of the haploid genome were found to be polymorphic for C-banding patterns. Chromosome A had four variants, chromosome E three variants and each of the chromosomes B, D, and F two variants. Chromosomes E and G were polymorphic for arm length and arm ratio.

Giemsa C-banded karyotypes of Hordeum marinum and H. murinum

Giemsa C-banding patterns of the predominantly self-pollinating, annual species Hordeum marinum (2x, 4x) and H. murinum (2x, 4x, 6x) showed mostly very small to small bands at centromeric and telomeric positions, at one or both sides of the nucleolar constrictions, and at intercalary positions with no preferential disposition. A similar distribution of bands has been observed in other Hordeum species, suggesting that the pattern is the basic one in the genus Hordeum. Hordeum murinum, especially the hexaploid cytotype, was distinguished from H. marinum by having more numerous and more conspicuous bands, resulting in a significantly higher percentage of constitutive heterochromatin (9–17 vs. 4–8%). The differences in C-banding patterns supported by differences in chromosome morphology confirm that H. marinum and H. murinum are not closely related. Banding-pattern polymorphism was prevalent among populations but unobserved within populations. In spite of this polymorphism, banding patterns in combination with chromosome morphology identified homologous chromosomes of different populations of a taxon and indicated that the chromosome complements of the polyploids of both species comprised the genome of the related diploid as well as one or two "unidentified" genomes. This agrees with an alloploid origin of polyploids. The C-banding patterns of H. marinum ssp. marinum and H. marinum ssp. gussoneanum (2x) showed some divergence in spite of the close relationship. The C-banded karyotypes of H. murinum ssp. murinum and H. murinum ssp. leporinum (4x) were very similar, supporting conspecificity. Chromosome lengths and longest/shortest chromosome ratios were fairly similar to those previously published, supporting the conclusion that linear relationships of chromosomes are normally stable within genomes. The taxonomy of the two species is discussed.Key words: C-banding, karyotypes, Hordeum.

Elimination and duplication of particular Hordeum vulgare chromosomes in aneuploid interspecific Hordeum hybrids

Seeds formed in crosses Hordeum lechleri (6x) x H. vulgare (2x and 4x), H. arizonicum (6x) x H. v. (2x), H. parodii (6x) x H. v. (2x), and H. tetraploidum (4x) x H. v. (2x) produced plants at high or rather high frequencies through embryo rescue. Giemsa C-banding patterns were used to analyze chromosomal constitutions and chromosomal locations on the methaphase plate. Among 100 plants obtained from H. vulgare (2x) crosses, 32 plants were aneuploid with 2n=29 (1), 28 (3), 27 (13), 26 (5), 25 (4), 24 (4), or 22 (2); 50 were euploid (12 analyzed), and 18 were polyhaploid (5 analyzed). Four plants had two sectors differing in chromosome number. Two of four hybrids with H. vulgare (4x) were euploid and two were aneuploid. Parental genomes were concentrically arranged with that of H. vulgare always found closest to the metaphase centre. Many plants showed a certain level of intraplant variation in chromosome numbers. Except for one H. vulgare (4x) hybrids, this variation was restricted to peripherally located non-H. vulgare genomes. This may reflect a less firm attachment of the chromosomes from these genomes to the spindle. Interplant variation in chromosome numbers was due to the permanent elimination or, far less common, duplication of the centrally located H. vulgare chromosomes in all 34 aneuploids, and in a few also to loss/gain of non-H, vulgare chromosomes. This selective elimination of chromosomes of the centrally located genome contrasts conditions found in diploid interspecific hybrids, which eliminate the peripherally located genome. The difference is attributed to changed "genomic ratios'. Derivatives of various H. vulgare lines were differently distributed among euploid hybrids, aneuploids, and polyhaploids. Chromosomal constitutions of hypoploid hybrids revealed a preferential elimination of H. vulgare chromosomes 1, 5, 6, and 7, but did not support the idea that H. vulgare chromosomes should be lost in a specific order. H. vulgare SAT-chromosomes 6 and 7 showed nucleolar dominance. Aneuploidy is ascribed to the same chromosome elimination mechanism that produces haploids in cross-combinations with H. vulgare (2x). The findings have implications for the utilization of interspecific Hordeum hybrids.

C-banding and nucleolar activity of tetraploid Avena species

The Giemsa C-banding pattern of the chromosomes of five tetraploid species of Avena have been studied. The chromosomes of AABB species (A. barbata, A. vaviloviana, and A. abyssinica) had similar C-banding patterns to those of A genome species. AACC species (A. maroccana and A. murphyi) possessed two sets of seven chromosome pairs with C-banding patterns similar to those observed in the diploid A and C genome species. However, no good correspondence between either of these two chromosome groups and any one diploid species has been found. When the nucleolar organizer activity of the species was analysed by silver staining, fewer nucleoli and nucleolar organizer regions (NORs) were observed than expected, assuming complete additivity of those from the donor diploid species.Key words: C-banding, NOR, Avena, heterochromatin.

Karyosystematics and evolution of AustralianAnnonaceae as compared withEupomatiaceae, Himantandraceae, andAustrobaileyaceae

Chromosome counts are presented for 12 genera and 20 species of AustralianAnnonaceae (all diploid with 2n = 16 or 18; Table 1) and two species ofEupomatiaceae (2n = 20, partly from Papua New Guinea). Detailed studies on interphase nuclear structure, condensing behaviour of chromosomes, and fluorochrome and Giemsa C-banding patterns also includeHimantandraceae (Galbulimima) andAustrobaileyaceae. — Eupomatiaceae completely correspond withAnnonaceae karyologically, their base number 2n = 20 is interpreted to have evolved from 2n = 18 by ascending dysploidy from common ancestors.Eupomatia laurina andE. benettii differ in DNA and constitutive heterochromatin (hc) quantity; their evolution from high to low DNA content probably corresponds to general progressions inMagnoliidae. Austrobaileya has nuclei of the presumably primitive “Tetrameranthus type” which is closely related to that ofGalbulimima and several other primitive taxa inMagnoliidae. Karyomorphology and other characters support the maintainance of two main branches within theMagnoliidae, Laurales andMagnoliales, withAustrobaileya probably intermediate; theWinteraceae appear more remote.—InAnnonaceae the reestablishment ofAncana is underlined by its chromosome number (2n = 18) the unexpected and specialized disulcate pollen, and various morphological characters which point to a close alliance with the Australian endemic generaFitzalania andHaplostichanthus (also disulcate) and the American genus pairSapranthus/Desmopsis; they are united in the provisionalSapranthus tribe, with a more distant position toFissistigma s. str. (2n = 16). AustralianAnnonaceae exhibit a high generic and a low species diversity; they can be considered as an ± old and partly impoverished outpost of the family with phytogeographical relationships to Asia, Africa and America.—On the base of field observations three main types of floral development inAnnonaceae are proposed, the most elaborated one found in the fly pollinated genusPseuduvaria. The growth form change from shrubs to lianas during the ontogeny ofDesmos andMelodorum, the vegetative propagation of anAncana species and the ecological and evolutionary patterns of the taxa investigated are discussed.

Cytological diversity inPellia endiviifolia(Dicks.) Dum

AbstractExtensive cytological variation between British populations of Pellia endiviifolia (Dicks.) Dum. (n = 8+x/y) permits the recognition of six distinct karyotypes; one of them found also in Greece and another in the U.S.S.R. Although based on typically small amounts of constitutive heterochromatin, Giemsa C-banding patterns serve to identify each of three chromosomes, 1, 6 and 9, as dimorphic or polymorphic. Relative proportions of chromosomes differ between karyotypes and further variation relates toa nucleolar organiser region (NOR) on chromosome 6 of one population in addition to the NOR generally located in chromosome 7. These findings have repercussions intaxonomy and reproductive behaviour that are discussed in detail.

Analysis of karyotypes and Giemsa C-banding patterns in eight species of Arachis

The karyotypes and Giemsa C-banding patterns of the chromosomes in eight species of Arachis L. have been studied. Six species are diploid with 20 chromosomes and two are tetraploid with 40 chromosomes. One diploid species (A. rigonii Krap. et Greg.) belongs to the sect. Erectoides and the rest belong to the sect. Arachis. Among the diploid species from the sect. Arachis, A. batizocoi Krap. et Greg, has a unique karyotype while others have similar karyotypes. Two tetraploid species, A. monticola Krap. et Greg, and A. hypogaea L., possess the most similar karyotypes. However, the diploid species, A. rigonii, from sect. Erectoides, has a karyotype distinguishable from those in sect. Arachis. The C-banding patterns of the chromosomes have been obtained for all the species. The centromeric bands have been found in all the chromosomes and the intercalary bands can be identified in a varied number of chromosomes among these complements. However, the telomeric bands only exist in one or two chromosomes. The comparison of banding patterns demonstrated that structural differences exist among the chromosomal complements of the species with similar chromosome morphology. The karyotype variation among the different species and interspecific relationship are discussed. It is suggested that all the diploid species with the A genome are closely related. There are close relationships between the tetraploid species and diploid species with the A or B genome within sect. Arachis. Key words: Arachis, cytology, karyotypes, Giemsa C-banding.

Cytological identification of telotrisomic and double ditelosomic lines in Secale cereale cv. Heines Hellkorn by means of Giemsa C-banding patterns and crosses with wheat–rye addition lines

Seven telotrisomic lines (1RS, 1RL, 2RS, 2RL, 3RS acro, 5RS, and 6RS), two double monotelosomic, and two double ditelosomic lines of Secale cereale cv. Heines Hellkorn were analyzed by means of Giemsa C-banding techniques. In crosses with several wheat–rye chromosome addition lines, the telosomic chromosomes in double ditelosomic lines 1/23 and 3/23 were found to be homologous to chromosomes 1R and 2RL of cv. Imperial rye. The C-banding pattern observed for the telosomes in these lines was similar to that detected in the 1R and 2R telosomics of the corresponding telotrisomic lines. Key words: Secale cereale, telotrisomics, double ditelosomics, C-banding pattern.