Karyological Studies Research Articles

Karyological diversity of wild Rosa in Yunnan, southwestern China

Wild Rosa resources in Yunnan are very abundant and hold many important and useful traits for improving modern rose. However, many of them have no cytological data and few were karyologically analysed. In this article, karyological study of 24 wild Rosa taxa belonging to different sections was carried out by means of traditional squashing and pressing. The chromosome number of 8 taxa and karyotypes of most studied ones were reported for the first time. 22 resources were diploids with 14 chromosomes (2n = 2x = 14), while Rosa moyesii Hemsl. et Wils. and Rosa macrophylla Lindl. from Sect. Cinnamomeae DC. were hexaploids with 42 chromosomes (2n = 6x = 42). Only type 1A and type 2A been found, karyotypes of genus Rosa in Yunnan were symmetric. Also, the studied taxa differed much from each other in chromosome length, position of centromere, satellite position and satellite number, etc. The results implied that wild Rosa germplasm in Yunnan were rich in karyologcal diversity, and polyploidization might have played and were still playing very important roles in the evolution and speciation in genus Rosa, mainly in Sect. Cinnamomeae in alpine areas of northwestern Yunnan. The cytological data would supply chromosomal proofs not only for the taxonomy, phylogeny and evolution of genus Rosa in this special geological area, but also for the exploitation of useful traits of wild Rosa into the breeding of new cultivars.

Karyological studies on someCrocusL. taxa from Turkey

Chromosome numbers and morphometric parameters of five Crocus L. taxa were examined. Except C. specious Bieb.subsp. specious, and C. olivieri Gay subsp. olivieri, the other 3 taxa, C. abantensis T. Baytop et Mathew, C. ancyrensis (Herbert) Maw, and C. biflorus Miller subsp. pulchricolor (Herbert) Mathew all are endemic for Turkey. The chromosome numbers of C. abantensis 2n = 8 chromosomes, six of them metacentric and two were submetacentric, C. ancyrensis and C. olivieri subsp. olivieri both had 2n = 6 chromosomes and all the chromosomes were subtelocentric, finally C. specious subsp. specious and C. biflorus subsp. pulchricolor both had 2n = 8 chromosomes and all were submetacentric. Although some of the taxa chromosome numbers were known from previous studies, in this study some different counts were and their detailed karyotypes were presented.

Karyological studies of some representatives of Tanacetum L. (Anthemideae-Asteraceae) from north-east Anatolia

The karyotypes of nine Tanacetum taxa distributed in north-east Anatolia, Turkey, were determined and evaluated by cluster analysis and principal-components analysis. Chromosome numbers were 2n = 2x = 18 (8 taxa) and 4x = 36 (1 taxon). Somatic chromosome numbers of two taxa and a new ploidy level in one taxon are reported for the first time. Karyotype analysis indicated that chromosomes of Tanacetum taxa have predominantly median centromeres. The taxa studied differed significantly in the size of the short arms and long arms, and the arm ratio of each pair of homologous chromosomes, indicating structural rearrangements of the chromosomes have been involved in diversification of the taxa. They were placed in 2A, 3A, and 2B of Stebbins’ karyotype classification, showing the presence of a primitive symmetrical karyotype in the genus. Several systematic and evolutionary aspects of the genus are discussed on the basis of karyological data.

A chromosomal study of two dormouse species from Turkey

The results of a karyological study on the dormice Myoxus glis ( 2n =62) and Dryomys nitedula ( 2n =48) from Turkey are presented in this study. The karyotype was analyzed cytogenetically by conventional staining, G- and C-banding techniques and the banding patterns were compared with those from previous works. The C-banded karyotype of M. glis is reported here for the first time. Furthermore, the G- and C-banding patterns are also provided for the first time in Black Sea Region populations in Turkey of the two species. C–banding showed in most autosomes at least faint heterochromatic bands in the centromeric regions in both species. The comparison of our G-banding patterns for these species with those of previous studies showed extensive homology.

Karyological Studies of <i>Aconitum brachypodum</i> and Related Species

A karyological study has been carried out on 6 populations of Aconitum brachypodum across its distribution region. All populations of the Aconitum brachypodum studied are diploid (2n=2x=16) with various chromosome morphologies. Karyological studies have been also carried out on 4 closely related species: A. pseudostapfianum, A. vilmorinianum var. altifidum, A. pukeense, A. ludlowii, A. pendulum and A. brachypodum var. laxiflorum, it is first time to conduct karyological studies on the first 4 species. All 7 species studied are thus diploid with the chromosome number of 2n=2x=16. Combining the available chromosome studies, the Aconitum has relatively consistent chromosome diversification with a basic number of 8, and most species contain diploid individuals, which suggested Aconitum is at the initial phase of polyploid diversification.

Étude caryologique et morphométrique du Mulot sylvestre (Apodemus sylvaticus : Muridae) au nord de la Tunisie

Apodemus sylvaticus (Linnaeus 1758) is a nocturnal rodent (Muridae), it is frequent in regions with soft and humid climate. This study takes on specimens captured in Lansarine, a region from the North of Tunisia. The Karyological study show us that the diploid number of the current population is stable in comparison with the European populations (Spain, Czech Republic), it is equal to 48 chromosomes with a fundamental number of autosomes equal to 46. The morphometric analysis, with body (T + C ; Q ; O ; PP ; Pds) (Chappelier 1927) and cranial parameters (LT ; lBC ; D ; MS ; CB) (Chimimba & Dippenaar 1995) considered, show us that our measurements integrate perfectly with the limits established by other authors in Tunisia. However, we find out some differences with other populations studied in Europe (Turkey, France), indeed our specimens looks bigger. Those differences are probably due to climat and the nature of diet.

Karyological studies in ten species of Citrus (Linnaeus, 1753) (Rutaceae) of North-East India

Ten Citrus (Linnaeus, 1753) species of North-East India have been karyo-morphologically analysed. All studied species had 2n=18 chromosomes without any evidence of numerical variation. All the chromosomes were found to be of metacentric and sub-metacentric in all the species; the morphology of the chromosomes showing size difference only. Symmetrical karyotype which does not have much difference in the ratio of longest to shortest chromosome in all the species was observed. Three species, Citrus grandis (Osbeck, 1757), Citrus reticulata (Blanco, 1837) and Citrus medica (Linnaeus, 1753) are identified as true basic species from asymmetry studies of karyotypes as they reflect on the primitive nature of their genomes. Citrus indica (Tanaka, 1937)occupies a special taxonomic position within the genus Citrus as a progenitor for other cultivated species.

Karyological studies on eight species of Onobrychis genus in Turkey

This study used karyological techniques to determine the chromosome numbers and morphology of eight species of Onobrychis L. (O. caput-galli (L.) Lam, O. aequidentata (Sibth. & Sm.) d’ Urv, O. fallax Freyn & Sint. var. fallax, O. lasiostachya Boiss, O. viciifolia Scop., O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu, O. hypargyrea Boiss. and O. cappadocica Boiss.). The results of this study determined the chromosome numbers of O. cappadocica as 2n = 16; O. viciifolia as 2n = 28 and the other species as 2n = 14 The karyotypes of species consisted of median-centromeric (m) or submedian-centromeric (sm) chromosomes. However, O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu was found to have only the median-centromeric (m) chromosomes. According to the results of the present study, of the eight Onobrychis taxa, only O. hypargyrea has a pair of satellite chromosomes (sat-chromosome). Furthermore, this study detected karyotype asymmetry.

Comparative chromosome mapping of the rRNA genes and telomeric repeats in three Italian pine voles of the Microtus savii s.l. complex (Rodentia, Cricetidae)

The Microtus (Terricola) savii s. l. complex is a group of five species/subspecies of the Italian pine voles, which diverged at different times either with or without chromosomal differentiation. The evidence of chromosomal diversification has so far concerned the shape of the sex chromosomes, especially the X chromosome. Three taxa of the group, Microtus savii savii, Microtus savii nebrodensis, and Microtus savii tolfetanus have identical karyotypes with metacentric X chromosomes. The X chromosomes of Microtus brachycercus and Microtus brachycercus niethammericus are, respectively, subtelocentric and acrocentric in shape. The Microtus savii complex has been long an object of conventional karyological studies, but comparative molecular cytogenetic data were completely missing. Therefore, we conducted a comparative chromosomal mapping of rRNA genes (rDNA) and telomeric repeats in three of the five taxa of the group: Microtus savii savii, Microtus savii nebrodensis, and Microtus brachycercus niethammericus, each of which belongs to a distinct mitochondrial clade.The survey revealed that differentiation of the clades was accompanied by remarkable changes with regard to the number and locations of the rDNA sites. Thus, Microtus savii savii and Microtus savii nebrodensis have especially high numbers of rDNA sites, which are located in the centromeric regions of, correspondingly, 18 and 13 chromosome pairs, whereas Microtus brachycercus niethammericus shows variable (8–10) and heteromorphic rDNA sites on both centromeric and telomeric regions. Interstitial telomeric sites (ITS), which are believed to indicate possible breakpoints of recurring chromosomal rearrangements, are present on the largest biarmed chromosomes and on the metacentric X chromosomes in Microtus savii savii and Microtus savii nebrodensis. These preliminary results are discussed in the context of recent advances in phylogeny of the group, as well as the rDNA genomic organization and X chromosome rearrangements in the genus Microtus.

A karyological study of the genus Pnigalio Schrank (Hymenoptera: Eulophidae): Assessing the taxonomic utility of chromosomes at the species level

We provide a karyological study of 12 species of the genus Pnigalio in an attempt to evaluate the taxonomic utility of karyotypes at the species level. For all species of Pnigalio examined the number of chromosome was 2n=12. Karyotype formulae presented mainly metacentric and submetacentric chromosomes, although a pair of acrocentrics or subtelocentrics, shorter than biarmed chromosomes, was present in some species. The analysis of karyotypes of Pnigalio showed frequent but not general interspecific variability of the chromosome traits. Although most of the studied species revealed concordance between morphological and karyological characters (centromeric index and relative length), two other categories have been identified: morphologically distinct species without reciprocal differences in karyotype structure, and morphologically similar species that strongly differ in chromosomal characters.

Chromosomal location of Ag/CMA3-NORs, 5S rDNA and telomeric repeats in two stickleback species

During the last 10 years, the stickleback has emerged as a promising model system in several biological fields. In particular, it is one of the most investigated fish groups by evolutionary biologists, as a model for understanding the genetic and molecular basis in processes of adaptive radiation, microevolution and development, as well as the genetic basis of sex determination. To provide karyological information about stickleback fish we performed cytogenetic analysis of the threespine stickleback (Gasterosteus aculeatus L.) and the ninespine stickleback (Pungitius pungitius L.). Diploid chromosome number in both species equalled 42; however, the chromosome arm numbers were 62 and 70, respectively. In the threespine stickleback, multichromosomal location of silver (AgNO3) and chromomycin A3 (CMA3) positively stained Nucleolar Organizer Regions (Ag/CMA3-NORs) was observed. The number of silver-stained chromosomes varied among different individuals from two to six. The Ag/CMA3-NORs covered almost entire short arms of one pair of middle-sized submetacentric chromosome pairs in the ninespine stickleback. In one male, the only Ag-NOR was situated telomerically on the long arm of the Y chromosome. The 5S rDNA clusters were observed on short arms of one pair of subtelocentric chromosomes in the threespine stickleback and four pairs of subtelo-acrocentric chromosomes in the ninespine stickleback of both sexes. Chromosome rearrangements responsible for the stickleback karyotype polymorphisms did not leave any internally located telomeric sequences. The results obtained in two stickleback species are therefore of considerable interest and further karyological studies should be carried out on the other populations of the wide species range in order to provide a more general picture of karyoevolutive trends in Gasterosteidae.

A new karyotype of Wiedomys pyrrhorhinus (Rodentia: Sigmodontinae) from Chapada Diamantina, northeastern Brazil

A new karyotype of Wiedomys pyrrhorhinus (Wied, 1821) is described, including G- and C-banding and Ag-NOR sites from specimens collected in the municipality of Morro do Chapeu, situated in the northern region of the Chapada Diamantina, state of Bahia. Karyological studies of W. pyrrhorhinus have shown a constant diploid number (2n) of 62 with two different numbers of autosomal arms (FNa): 86 and 90, respectively. The new karyotype revealed 2n = 62 and FNa = 104, being the higher autosomal number found so far for this genus. The X chromosome is a large acrocentric and the Y chromosome is a small acrocentric. The analysis of the karyotype morphology suggests that this new karyotype is more closely related to the previous karyotype with 2n = 62 and FNa = 90, described from Caetite, Bahia State. Further studies, comparing different populations of W. pyrrhorhinus, including molecular approaches, may help to better understand the geographical limits of each population and their phylogenetic relationships in the Caatinga biome

A karyological study ofGenistasect.SpartocarpusSpach (Cytiseae-Fabaceae)

Summary Genista sect. Spartocarpus includes about 20 taxa distributed in the Mediterranean region, with one species (G. radiata) extending into the Alps. Two main diversity centers can be identified: one in the East (Balkan Peninsula and Anatolia) and one in the West (Southern Spain and Northwestern Africa), with various species occurring in the Tyrrhenian area. A karyological study was carried out on 30 wild populations of 7 taxa; a comprehensive evaluation of the section is presented. In the G. radiata group (East-Alpine Balkan), both varieties of G. radiata (radiata and sericopetala) and G. holopetala have the same secondary basic chromosome number x = 12, but different levels of ploidy: 4x (2n = 48) in var. radiata and G. holopetala; 8x (2n = 96) in var. sericopetala of Southeastern France; both 4x and 8x (2n = 48 and 2n = 96) in the examined population of Piemonte; G. hassertiana (2n = 52) may be considered as the result of ascending aneuploidy derived from x = 12. The G. sessilifolia group (Central Southern Balkans and Anatolia) appears karyologically homogeneous, displaying the basic number x = 11: G. nissana (2n = 22) is diploid, while in G. sessilifolia, ssp. romanica (Southeastern Europaean, 2n = 22) is diploid and ssp. sessilifolia (Anatolian, 2n = 88) octoploid. In the Western Mediterranean region, G. spartioides and G. haenseleri (Southern Spain and Northwestern Africa) display n = 20 and 2n = 40 (rarely n = 22), with x = 10. In G. aetnensis, endemic to Sardinia and Sicily, the numbers n = 26 and 2n = 52 were found, with x = 13. For the Tyrrhenian species of the G. ephedroides complex (incl. G. dorycnifolia) the number 2n = 48 (with x = 12) has been constantly counted. Sect. Spartocarpus is thus karyologically heterogeneous, displaying four secondary basic numbers (x = 10, 11, 12, 13), that have different geographic patterns and probably diversified following geographical isolation. Besides, more levels of ploidy (2x, 4x, 8x) and some cases of aneuploidy were observed: the level 4x is the most frequent and prevails in all the range of the section, 2x is found only in Southern Balkans (G. sessilifolia group) and 8x is limited to peripheral areas of Turkey and France.

Karyology ofTelineMedik. (Cytiseae-Fabaceae)

Summary The genus Teline includes about 20 taxa in the Mediterranean and Macaronesian Regions. Two diversity centres can be recognized: the Canary Islands (where the highest diversity is found) and the Western part of the Mediterranean area. A karyological study was carried out on 30 wild populations of 16 taxa; a comprehensive evaluation of the genus is here presented, considering the previous references as well. The Western Mediterranean species T. linifolia, T. patens, T. tribracteolata and T. osmariensis, and the Canarian taxa T. stenopetala, T. osyrioides (including ssp. sericea), T. microphylla, T. hillebrandii, T. rosmarinifolia ssp. rosmarinifolia and T. splendens show the chromosome numbers n = 24 and/or 2n = 48, sometimes with up to 4 B chromosomes. Both numbers 2n = 46 and 2n = 48 were counted in the Mediterranen species T. monspessulana and in the Macaronesian taxa T. maderensis, T. canariensis and T. nervosa. The genus Teline is thus quite homogeneous karyologically. In all the species, the eutetraploid number 2n = 48 was found, being by far the most common in Cytiseae and traceable to the secondary basic number x = 12. In some taxa, along with the number 2n = 46, also a tendency towards descending aneuploidy was observed, not very common in Genista, but more frequent in Cytisus. A certain correspondence between the karyological and molecular data (Percy & Cronk, 2002) might be observed: the taxa of the “T. linifolia group” constantly show the somatic number 2n = 48 (very rarely, 2n = 46 in T. nervosa), while in the taxa of the “T. monspessulana group”, both euploid (2n = 48) and aneuploid (2n = 46) numbers are often counted.

Comparative chromosome and molecular studies of some species of genus Arum from eastern Slavonia and Baranya region in Croatia

Karyological and molecular studies were done in this paper on three species of genus Arum; <em>Arum italicum</em> Mill. and <em>Arum maculatum</em> L., with two varieties, and <em>Arum alpinum</em> Schott and Kotschy, also with two varieties. The main goal of this paper was to establish whether they were regularly determined exclusively on the principle of morphological parameters. Karyological studies showed that the number of chromosomes for<em> Arum italicum</em> Mill. amounted to 2n=84, for <em>Arum maculatum</em> L. 2n=56 and for <em>Arum alpinum</em> Schott and Kotschy 2n=28. This confirmed that these species are not only clean and separated, but also support the regularity of the morphological determination. Molecular studies, e.g. RAPD method showed that two genetically separated species groups correspond to the three mentioned species. <em>Arum italicum</em> Mill. is the least homogenous species closely related and the variability between populations is high. <em>Arum maculatum</em> L. is more homogenous within the species, two varieties could be differentiated whereas they are closely genetically related and the variability between the populations is too high. <em>Arum alpinum</em> is strongly homogenous and within these species two varieties could also be differentiated. That means that they are closely related and the variability between the populations is very high. These observations mostly coincided with previous morphological investigations.

G- and C-banded karyotypes of Hazel Dormouse, Muscardinus avellanarius trapezius(Mammalia: Rodentia) in Turkey

The results of a karyological study on the hazel dormouse Muscardinus avellanarius trapezius from Turkey were presented in this study. Using conventional staining and G- and C-banding techniques, 10 specimens were cytogenetically studied. The G- and C-banding patterns of Turkish specimens of this subspecies were provided for the first time in this study. The karyotype was composed of 2n = 46, NF = 90 and NFa = 86. A secondary constriction was visible in one pair of metacentrics (no. 9). All of the chromosomes possessed heterochromatic bands in the centromeric and pericentromeric regions. The X chromosome was a medium-sized metacentric and the heterochromatic region was restricted to the centromere. The Y chromosome was a very small acrocentric and possessed small centromeric block of heterochromatic.

Karyotype Study of 5 Species of the Family Viverridae in Thailand by High Resolution GTG-Banding Technique

As endangered species in Thailand, the wild animal species of the common palm civet (Paradoxurus hermaphrodites), masked palm civet (Paguma larvata), large Indian civet (Viverra zibetha), large-spotted civet (Viverra megaspila), and binturong (Arctictis binturong) were selected for karyological study. Blood samples were taken from 1 male and 1 female of each species. After the standard whole blood lymphocyte culture in the presence of colchicine, the prometaphase spreads were performed on microscopic slides and air-dried. High resolution GTG-banding technique was applied to stain the chromosomes. The results showed that 2n (diploid) of Par. hermaphrodites, Pag. larvata, V. zibetha, V. megaspila and A. binturong were 42, 44, 38, 38, and 42, respectively. The autosomes presence of metacentric, submetacentric, acrocentric and telocentric autosomes were 6-10-14-10, 6-8-12-16, 8-6-18-4, 4-12-16-4 and 6-12-4-18, respectively. The X chromosome were submetacentric, submetacentric, metacentric, submetacentric and metacentric, and the Y chromosome were submetacentric, acrocentric, telocentric, telocentric and acrocentric chromosome, respectively. The numbers of bands in one set of prometaphase haploid chromosomes from the high resolution GTG-banding technique were 233, 262, 198, 222, and 247 bands, respectively and each chromosome pair could be clearly differentiated.

A karyological study of six species of Silene L. (Caryophyllaceae) from the Hengduan Mountains, SW China

Karyology of six Silene (Caryophyllaceae) species from the Hengduan Mountains of SW China was analyzed for the first time. The results indicate that the basic chromosome number for the six species is x=12, with karyotypic formula as follows: S. orientalimongolica (2n=2x=24=24m); S. nepalensis (2n=2x=24=16m+8sm); S. trachyphylla (2n=2x=24=8m+6sm+10st); S. davidii (2n=4x=48=48m); S. nigrescens (2n=4x=48=40m+8sm); S. yetii (2n=6x=72=64m+8sm). The karyotype asymmetry of S. orientalimongolica and S. davidii are 1A and S. trachyphylla is 3A, distinct from the other three species with 2A type. The significance of the cytological evolution of Silene from the Hengduan Mountains is briefly discussed.

A wide hybrid zone of chromosome races of the common shrew, Sorex araneus Linnaeus, 1758 (Mammalia), between the Dnieper and Berezina Rivers (Belarus)

Karyological study of 75 specimens of the common shrew, Sorex araneus Linnaeus, 1758, from 8 localities in the Berezina River basin (eastern Belarus) was carried out. A wide hybrid zone (not less than 100 km) between the northern West Dvina chromosome race (XX / XYY, af, bc, gm, hk, ip, jl, no, qr, tu) and the southern Turov race (XX / XYY, af, bc, g, h/k, i, jl, m, n, o, p, q, r, tu) was revealed in this region. Frequencies of fused-unfused arms comprising four diagnostic metacentrics of the West Dvina race (g/m, h/k, n/o, q/r) were calculated in all capture sites. Taking into consideration the absence of metacentric ip in specimens from six northern localities, the Borisov (Bs) race (XX / XYY, af, bc, g/m, h/k, i, jl, n/o, p, q/r, tu) (Orlov, Borisov, 2009) was distinguished in these sites. Common shrews from two southern localities on the right and left banks of the Berezina River (Berezino vicinity) were referred to the Turov race. The presence of four metacentrics descended from the West Dvina race in the Bs race testifies to the hypothesis expressed earlier that the polymorphic populations of the S. araneus between the Dnieper and Berezina Rivers originated as a result of the West Dvina race spreading from the north and of hybridization between this race and local populations with acrocentric chromosomes.

Larch chromosomal mosaicism

Karyological study of larch population members from different parts of the Larix olgensis L. Henry areal in the Primorskii krai has been carried out. The main amount of chromosomes for larch as n = 12 (2n = 24) has been confirmed. Mixoploidy was observed in all studied populations. The difference of individuals from the larch areal based on the cell amount with a different level of ploidity has been found in the population of L. olgensis locus classicus and both L. sibirica and L. gmelinii, which is probably a consequence of their hybrid nature.