A new chromosomal race (2n=44) of Nannospalax xanthodon from Turkey (Mammalia: Rodentia)

A new karyotype for blind mole rats was recorded in Tunceli province in Eastern Turkey. The karyotype contained 44 chromosomes, including 13 biarmed pairs, 7 acrocentric pairs, and one heteromorphic pair with a submetacentric and an acrocentric homologue in the autosomal complement (FNa=69). The X chromosome was submetacentric and the Y chromosome medium-sized subtelocentric (FN=73). Distinct dark centromeric C-bands were observed on most of the biarmed and three pairs of the acrocentric autosomes. The NORs were detected on short arms of three subtelocentric pairs and one acrocentric pair of autosomes. The diploid number of chromosomes and the karyotype characteristics observed are obviously unique among hitherto studied populations of blind mole rats and the complement can be evaluated as a new chromosome race of Nannospalax xanthodon. The distribution ranges of individual chromosome races of the species recorded in Eastern Anatolia are revised and possible interracial hybridization is discussed in respect of the finding of a new race.     

C-banding and FISH in chromosomes of the blow flies Chrysomya megacephala and Chrysomya putoria (Diptera, Calliphoridae)

The blow flies Chrysomya putoria and C. megacephala have 2n=12 chromosomes, five metacentric pairs of autosomes and an XX/XY sex chromosome pair. There are no substantial differences in the karyotype morphology of these two species, except for the X chromosome which is subtelocentric in C. megacephala and metacentric in C. putoria and is about 1.4 times longer in C. putoria. All autosomes were characterized by the presence of a C band in the pericentromeric region; C. putoria also has an interstitial band in pair III. The sex chromosomes of both species were heterochromatic, except for a small region at the end of the long arm of the X chromosome. Ribosomal genes were detected in meiotic chromosomes by FISH and in both species the NOR was located on the sex chromosomes. These results confirm that C. putoria was the species introduced into Brazil in 1970s, and not C. chloropyga as formerly described.     

Karyotypes of the Genus Fritillaria from South Anhui

This paper reports chromosome numbers and karyotypes of five species of the genus Fritillaria from south Anhui. The origin of the material used in this work is provided in Table 1, micrographs of mitotic metaphase in Plate 1,2, and the parameters of chromosomes in Table 2. Except F. thunbergii Miq., the karyotypes and chromosome numbers of all the species in this paper were studied for the first time. The results are shown as follows: 1. Fritillaria qimenensis D. C. Zhang et J. Z. Shao Collected from Qimen, Anhui, it has the karyotype formula 2n = 24+4Bs = 3m+lsm+8st (2sc)+12t (2sc)+4Bs (Plate 1:1, 2). The chromosomes range in length 8.72-19.13μm, with the ratio of the longest to the shortest 2.19. Therefore, the karyotype belongs to Stebbins’ (1971) 3B. The secondary constrictions are found on the long arms of 7th and 10th pairs. All the five B-chromosomes are of terminal centromeres. The two chromosomes of the second pair show heteromorphy (Fig. 1, E) with arm ratios 1.86 and 1.56 respectively. 2. Fritillaria monantha Miq. var. tonglingensis S. C. Chen et S. F. Yin Collected from Tongling, Anhui, this species is shown to have three chromosome numbers, 2n =24+5Bs, 2n=24+2Bs and 2n=24. This paper reports 2 cytotypes: Type I: 2n = 24+5Bs = 4m+8st (2sc) +12t (2sc) +5Bs (Plate 1: 3, 4). The chromosomes range in length from 10.40 to 22.19μm, with the ratio of the longest to the shortest 2.13. It belongs to 3B of stebbins’(1971) karyotypic symmetry. The secondary constrictions are found on the short arms of 7th and the long arms of 9th chromosome pairs. The metacentric B-chromosomes and the small satellites located on the short arms are major characters of this cytotype. Type II: 2n=24=2m+2sm+8st(2sc)+12t(2sc) (Plate 1:5, 6). The chromosomes range in length from 13.84 to 29.81μm, with the ratio of the longest to the shortest 2.15. The karyotype belongs to Stebbins’3B. The secondary constrictions are found on the long arms of 5th and 10th pairs. No B-chromosomes are found. 3. Fritillaria xiaobeimu Y. K. Yang, J. Z. Shao et M. M. Fang Collected from Ningguo, Anhui, it has karyotype formula 2n = 24 = 2m+2sm+10st (4sc) + 10t (Plate 2:7, 8). The chromosomes range in length from 13.86 to 26.27μm, with the ratio of the longest to the shortest 1.89. The karyotype belongs to stebbins’3A. The secondary constrictions are found on the long arms of 7th and 9th pairs. 4. Fritillaria ningguoensis S. C. Chen et S. F. Yin Collected from Ningguo, Anhui, it is of karyotype formula 2n = 24 = 2m+2sm+8st (2sc) +12t (Plate 2: 9, 10). The chromosomes range in length from 9.11 to 23.23μm, with the ratio of the longest to the shortest 2.55. The karyotype belongs to Stebbins’3B. The secondary constrictions are only found on the long arms of the 10 th pair. 5. Fritillaria thunbergii Miq. Collected from Ningguo, Anhui, it is of karyotype formula 2n = 24 = 2m+2sm+8st(2sc) +12t(2sc)(Plate 2:11, 12). The chromosomes range in length from 8.83 to 19.85μm, with the ratio of the longest to the shortest 2.25. The karyotype belongs to stebbins’3B. There are secondary constrictions on the long arms of 5th and 7th pairs. The karyotype of the Ningguo material is similar to that of the Huoqiu (Anhui) material reported by Xu Jin-lin et al. (1987), but it is obviously different from 2n=2m(sc)+2sm+4st(2sc)+16t (2sc) reported byZhai et al. (1985) for the material from Xingjiang, Northwest China.     

Karyotypes of two rare rodents, Hapalomys delacouri and Typhlomys cinereus (Mammalia, Rodentia), from Vietnam

Karyotypes of Hapalomys delacouri (Rodentia, Muridae) and Typhlomys cinereus (Rodentia, Platacanthomyidae) from Vietnam are described for the first time. The diploid karyotype of Hapalomys delacouri is 38 (NFa=48), consisting of six pairs of bi-armed and 12 pairs of acrocentric autosomes decreasing in size; plus a large metacentric X chromosome and Y chromosome, also metacentric, that is equal in size to the largest pair of acrocentric autosomes. The newly described karyotype differs significantly from that reported for Hapalomys delacouri from northern Thailand. The latter record very likely represents a different species of Hapalomys, possibly the taxon Hapalomys pasquieri described from north-central Laos.The diploid karyotype of Typhlomys cinereus is 38 (NF=48), consisting of five pairs of meta- to submetacentric and 14 pairs of acrocentric chromosomes varying in size from large to small; sex chromosomes were not defined.     

四种菊头蝠染色体组型分析

本文分析了皮氏菊头蝠(R. pearsoni chinensis),鲁氏菊头蝠(R.rouxi sinicus),角菊头蝠(R.cornutus pumilus)及中菊头蝠(R.affinis)的常规核型,现报道如下。     

Cytogenetic study of Callicebus hoffmannsii (Cebidae, Primates) and comparison with C. m. moloch.

Callicebus is a neotropical primate genus divided into four or five groups of species. Species of the moloch group are distributed in the tropical forests of the Amazon basin. The karyotype of Callicebus hoffmannsii (moloch group) was studied by means of G- and C-banding, Ag-NOR staining and in situ hybridization of telomeric probes. C. hoffmannsii had 2n = 50 chromosomes, with ten biarmed and fourteen acrocentric autosomal pairs. The X chromosome was submetacentric and the Y chromosome was a minor acrocentric. Constitutive heterochromatin was detected in the centromeric regions of all chromosomes; in pairs 7 and 10, it was found in the distal regions of the short arms, and distally in the long arm of the X chromosome. Size heteromorphism in C-bands was detected in pairs 7 and 10. Ag-NOR staining revealed a maximum of three nucleolar organizers. Telomeric probes hybridized only at the terminal regions of all chromosomes. Additionally, a comparison was carried out between C. hoffmannsii and C. m. moloch (2n = 48), as previously reported. Both species shared gross chromosomal similarities diverging by a single rearrangement of centric fusion/fission. A high similarity between C. hoffmannsii and C. donacophilus indicated a close association between the moloch and donacophilus groups.     

Characterization of G-banded chromosomes of a female saola (Pseudoryx nghetinhensis,2n = 50) and X chromosome i dentification by means of fluorescent in situ hybridization

The saola (Pseudoryx nghetinhensis) is a newly discovered large mammal species, belongs to the subfamily Bovinae and is listed as being endangered. Due to the limitation of the material available, no cytogenetic studies have been carried out on this species. In the present study, preliminary cytogenetic analysis was undertaken on cultured female fibroblast cells to characterize the karyotype organization of saola. An examination of 120 Giemsa stained metaphases showed the diploid chromosome number of 2n = 50, including five bi-armed chromosome pairs. The distribution of constitutive heterochromatin in saola was studied. However, the variability in the size of C-bands was not significant on all the homologous chromosomes. The X chromosome pair, corresponding to the largest telocentric chromosomes, was identified by fluorescent in situ hybridization (FISH) using a bacterial artificial chromosome clone (BAC 0577G05, which maps to BTAXq25-->q33). In comparison to the standard karyotype of cattle (ISCNDB 2000), a G-banded ideogram of saola (about 390 band level) was presented. This work, therefore, provided a basic insight into the karyotype organization of this endangered species and will be particularly useful to improve the understanding of differences of genomes between related species.     

A chromosome study ofSchistocephalus solidus (Müller, 1776) (Cestoda: Pseudophyllidea)

Analysis of Giemsa-stained metaphase plates of plerocercoids ofSchistocephalus solidus revealed the mode diploid number of chromosomes for this species as 2n=18. Chromosome pairs 1, 5, 6, 8 and 9 are metacentric, pairs 2, 4 and 7 are subtelocentric, and pair 3 is subtelocentric to acrocentric. The karyotype is characterised by mean absolute chromosome length between 1.9 and 5.9 m and a total chromosome length of the haploid complement of 32 m. A comparison with other known karyotypes of related species of pseudophyllidean cestodes was made.     

Chromosomes of the liver fluke, Clonorchis sinensis

A karyological study was carried out in order to compared the chromosome numbers, chromosome morphologies and karyotypes of the oriental liver fluke, Clonorchis sinensis (Trematoda: Opisthorchiidae), collected from Korea and China. Chromosome preparations were made by means of air-drying method. The chromosome number was 2n = 56 in both Korean and Chinese flukes, and chromosomes were divided into two groups based on this size; consisting of 8 pairs of large and 20 pairs of small chromosomes. However, the karyotypes showed some differences between Korean and Chinese flukes. The karyotype of liver flukes from Korea consisted of three metacentric pairs, one meta-/submetacentric pair, 16 submetacentric pairs and eight subtelocentric pairs of chromosomes. On the other hand, liver flukes from China consisted of two metacentric pairs, two meta-/submetacentric pairs, 16 submetacentric pairs and eight subtelocentric pairs of chromosomes.     

A cytogenetic study on the rodent tapeworm Rodentolepis myoxi

The karyotype of glirid tapeworm Rodentolepis myoxi (Rudolphi, 1819) (Cestoda: Hymenolepididae) comprises six pairs of small bi-armed chromosomes (2n = 12). All pairs of chromosomes possess uniform morphology, i.e. metacentric, submetacentric or meta-submetacentric types of structures. The formula of the karyotype structure is n = 2m + 1m-sm + 3sm. The absolute chromosome length ranges from 3.78 to 2.00 microm. The mean total length of the haploid complement is 15. 98 microm. The first pair (group A) is the largest, pairs 2 and 3 can be grouped into group B while pairs 4-6 are smaller and can be classified as group C. The number of chromosomes of R. myoxi is the same for the congeneric species, however, karyological characteristics differ from all recently known karyotypes of rodent hymenolepidids.     

Chromosomes of lemuriformes. II. Chromosome polymorphism in Lemur fulvus collaris (E. Geoffroy 1812).

Two previously unreported diploid numbers, 2N = 50 and 2N = 51, from five individual Lemur fulvus collaris are described. In both chromosome complements, the nombre fondamental is 64. The 2N = 50 complement is composed of 7 pairs of bi-armed chromosomes, 17 pairs of acrocentric chromosomes with small short arms, and acrocentric sex chromosomes. The 2N = 51 complement is identical with these exceptions: Only one member equivalent to bi-armed pair 6 of L.f. collaris (2N = 50) is present, and two extra acrocentrics are found in the 2N = 51 complement. G-banding analyses suggest that these chromosomes are a heteromorphic pair of the Robertsonian type. This conculsion is supported by evidence from studies of meiotic pairing relationships of the three chromosomes and the complements of hybrids resulting from interspecific matings. Comparison of the 2N = 50 and 2N = 51 complements with a published 2N = 48 complement suggests that these new karyotypes do not provide a lineal link between the 2N = 52 and 2N = 48 karyotypes (Rumpler, Y., and R. Albignac 1969 C.R. Soc. Biol., 163: 1989-1992).     

Constitutive heterochromatin, 5S and 18S rDNA genes in Apareiodon sp. (Characiformes, Parodontidae) with a ZZ/ZW sex chromosome system

Karyotype, sex chromosome system and cytogenetics characteristics of an unidentified species of the genus Apareiodon originating from Piquiri River (Paraná State, Brazil) were investigated using differential staining techniques (C-banding and Ag-staining) and fluorescent in situ hybridization (FISH) with 5S and 18S rDNA probes. The diploid chromosome number was 2n = 54 with 25 pairs of meta- (m) to submetacentric (sm) and 2 pairs of subtelocentric (st) chromosomes. The major ribosomal rDNA sites as revealed by Ag-staining and FISH with 18S rDNA probe were found in distal region of longer arm of st chromosome pair 26, while minor 5S sites were observed in the interstitial sites on chromosome pairs 2 (smaller cluster) and 7 (larger one). The C-positive heterochromatin had pericentromeric and telomeric distribution. The heteromorphic sex chromosome system consisted of male ZZ (pair 21) and female middle-sized m/st Z/W chromosomes. The pericentric inversion of heterochromatinized short arm of ancestral Z followed by multiplication of heterochromatin segments is hypothesized for origin of W chromosome. The observed karyotype and chromosomal markers corresponded to those found in other species of the genus.     

Karyological observations on Turbellaria Proseriata: karyometric analysis ofMonocelis fusca,M. lineata (Monocelididae) andParotoplana macrostyla (Otoplanidae)

A karyometric analysis of the chromosome set of the marine turbellariansMonocelis fusca, M. lineata andParotoplana macrostyla has been carried out. The karyotype of the twoMonocelis species investigated (2n=6) is formed by three pairs of small and similarly sized chromosomes: InM. fusca, chromosome 1 is metacentric, chromosome 2 acrocentric and chromosome 3 is subtelocentric.M. lineata also presents one pair of metacentric chromosomes (chromosome 2), while chromosomes 1 and 3 are submetacentric.P. macrostyla (2n=12) reveals two pairs of large metacentric and four pairs of small chromosomes, three of which are metacentric, whereas the last is subtelocentric.     

The karyotype of Brachyteles arachnoides (E. Geoffroy, 1806) (Primates: Platyrrhini)

The karyotype of one female Brachyteles arachinoides (E. Geoffroy, 1806) was studied. The specimen exhibited 62 chromosomes, which could be arranged in three clearly distinguishable groups: the first one including 5 pairs of subtelocentric chromosomes, the second one including 8 pairs of metacentric and submetacentric chromosomes and the third one including 18 pairs of acrocentric chromosomes. The X chromosome pair could not be identified.This study was supported by grants from CNPq (SIP 04/011), Brazil.     

Chromosomes of Heterobilharzia americana (Digenea: Schistosomatidae), with ZWA sex determination, from Louisiana

Mitotic chromosomes of Heterobilharzia americana from Louisiana are described from parasite material that was dissected from snails, air-dried on slides, and stained with conventional Giemsa and C-band methods. As in other schistosomes, the female is the heterogametic sex. This Louisiana strain, however, differs from a Texas strain and other schistosome species in that the male and female have different diploid numbers of chromosomes (male, 20; female, 19), and the strain has a ZZ male/ZWA female sex-determining mechanism. The chromosomes of the male resemble those of the Texas strain in number and morphology with the Z chromosomes being metacentric and the largest elements in the karyotype. The others form a series decreasing in size to very small number 10's. Chromosomes 2,3, and 4 are subtelocentric; 5 is subtelocentric to acrocentric and is satellited; 6 is submetacentric to subtelocentric; 7 is submetacentric; 8 is subtelocentric to submetacentric; 9 is metacentric to submetacentric; and 10 is metacentric. The female complement differs from the male of this strain in having only 1 normal chromosome 5. The other number 5 and most of the original W apparently have fused tandemly to form the WA chromosome (a "neo-W").     

大壁虎的染色体及减数分裂联会复合体的研究

大壁虎(Gekko gecko)的染色体数目为2n=38,核型由2对中着丝粒(Nos.1.4.)、3对亚中着丝粒(Nos.2.3.5)及14对端着丝粒和亚端着丝粒(Nos.6—19)染色体组成。一对核仁组织者(NOR_s),位于第7对端着丝粒染色体的末端。同时,本文还对大壁虎的减数分裂以及联会复合体(S.C)的结构和组型,进行了详细的观察和分析。     

Cytogenetic characterization and description of an XX/XY1Y2 sex chromosome system in catfish Harttia carvalhoi (Siluriformes, Loricariidae)

Karyotypic and cytogenetic characteristics of catfish Harttia carvalhoi (Paraíba do Sul River basin, S?o Paulo State, Brazil) were investigated using differential staining techniques (C-banding, Ag-staining) and fluorescent in situ hybridization (FISH) with 18S and 5S rDNA probes. The diploid chromosome number of females was 2n = 52 and their karyotype was composed of nine pairs of metacentric, nine pairs of submetacentric, four pairs of subtelocentric and four pairs of acrocentric chromosomes. The diploid chromosome number of males was invariably 2n = 53 and their karyotype consisted of one large unpaired metacentric, eight pairs of metacentric, nine pairs of submetacentric, four pairs of subtelocentric, four pairs of acrocentric plus two middle-sized acrocentric chromosomes. The differences between female and male karyotypes indicated the presence of a sex chromosome system of XX/XY1Y2 type, where the X is the largest metacentric and Y1 and Y2 are the two additional middle-sized acrocentric chromosomes of the male karyotype. The major rDNA sites as revealed by FISH with an 18S rDNA probe were located in the pericentromeric region of the largest pair of acrocentric chromosomes. FISH with a 5S rDNA probe revealed two sites: an interstitial site located in the largest pair of acrocentric chromosomes, and a pericentromeric site in a smaller metacentric pair of chromosomes. Translocations or centric fusions in the ancestral 2n = 54 karyotype is hypothesized for the origin of such multiple sex chromosome systems where females are fixed translocation homozygotes whereas males are fixed translocation heterozygotes. The available cytogenetic data for representatives of the genus Harttia examined so far indicate large kayotype diversity.     

Unequal X Chromosomes in Bradysia Hygida (Diptera:Sciaridae) Females: Karyotype Assembly and Morphometric Analysis

The mitotic chromosomes of Bradysia hygida(Diptera:Sciaridae) neuroblast cells are described together with their morphometric data. Giemsa-stained neuroblast chromosomes from female and male larvae confirm the chromosome number of this species, 2n=8 (XX) and 2n=7 (XO), respectively. The karyotype assembly reveals two metacentric autosomic pairs, the A and B chromosome; a subtelocentric, the C chromosome, the smallest one; and a sexual unequal metacentric pair, X chromosome, in female karyotype and a one sexual metacentric X chromosome in male. The implications of the unequal X chromosome pair are discussed.