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 human intestinal trematodes of the genus Metagonimus (Digenea: Heterophyidae) in Korea

In order to analyze chromosome numbers and karyotypes of intestinal trematodes belonging to the genus, Metagonimus, the gonad tissues of M. takahashii, M. miyatai, and M. yokogawai were prepared and examined. The number of bivalents in the first meiotic division of M. takahashii was nine (n = 9). The diploid number of M. miyatai was observed to be eighteen (2n = 18) and their chromosomes consisted of one pair of metacentric, 7 pairs of submetacentric, and one pair of telocentric chromosomes. The diploid number of M. yokogawai was thirty-two (2n = 32) and the chromosome complements were composed of two pairs of metacentric, 11 pairs of submetacentric, and three pairs of subtelocentric chromosomes. These results could be a supporting evidence for the validity of the new species, M. miyatai, distinct from M. yokogawai.     

湘华鲮(♂)×鲮鱼(♀)杂交一代与其双亲染色体组型的比较研究

三种鱼的二倍体数目完全相同,均为2n=50。三种鱼的核型差异较大,尤其是双亲间的组型在形态上有明显的差异。然而杂交一代的m、sm二组染色体的组型却十分接近母体,这二组的染色体数占了全部染色体总数的88%。杂交一代染色体组型中的st和t二组染色体虽与双亲有所不同,但与双亲中这二组染色体组型的差异来比要小一些。三种鱼的中期分裂相中,未曾发现带有随体的染色体,也未发现与性别有关的异型染色体的存在。       

中国刺猬的染色体研究

本文采用全血培养和骨髓染色体制片法,对分布于我国南京市郊和济南市郊的刺猬染色体进行了组型、C-带、G-带和银染色的观察分析,并与东欧、西欧两种刺猬比较,它们之间的核型及带型差异显著;又将南京、济南及金清波(1985)报道的河南新乡三地分布的刺猬进行比较,它们的核型及带型也显示出一定差异,这种多态性在分类和进化上有一定的意义。     

Cytogenetics of the razor clam Solen marginatus (Mollusca: Bivalvia: Solenidae)

The razor clam Solen marginatus has a diploid chromosome number of 38. The karyotype consists of one metacentric/submetacentric, three submetacentric/metacentric, five submetacentric, one submetacentric/subtelocentric, one subtelocentric/submetacentric, six subtelocentric and two telocentric chromosome pairs. Staining with chromomycin A3 revealed bright positive bands subcentromerically in the long arms of one medium-sized subtelocentric pair, while DAPI staining showed uniform fluorescence in all chromosomes of the complement. Fluorescence in situ hybridization using an 18S-5.8S-28S rDNA probe locates these loci at the subcentromeric region of one subtelocentric pair and at the subtelomeric region of another subtelocentric pair.     

Karyotype and Chromosomal Location of 18S–28S and 5S Ribosomal DNA in the Scallops Pecten maximus and Mimachlamys varia (Bivalvia: Pectinidae)

This work describes the karyotype and chromosomal location of the ribosomal DNA (rDNA) of Pecten maximus and Mimachlamys varia, two commercial scallop species from Europe. According to the chromosome centromeric index values found, the karyotype of P. maximus is composed of 1 metacentric, 2 metacentric–submetacentric, 1 telocentric–subtelocentric and 15 telocentric pairs, and that of M. varia of 4 metacentric, 2 subtelocentric–submetacentric, 9 subtelocentric, 3 subtelocentric–telocentric and 1 telocentric–subtelocentric pairs. In P. maximus, 18S-28S rDNA was located by FISH on a metacentric–submetacentric pair, and in M. varia on a subtelocentric–submetacentric pair using both silver staining and FISH. PCR amplification of the 5S rDNA unit yielded a single product of about 460 bp (P. maximus) and 450 bp (M. varia), that used as probe revealed a 5S rDNA site on a telocentric pair in P. maximus and a subtelocentric pair in M. varia. Two-color FISH or sequential silver staining of 5S rDNA-FISH-metaphases corroborated that the two gene families are located on different chromosomes in both species. A comparative analysis of the data allowed the inference of karyotypic relationships within scallops.     

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.     

Karyotypes of Cerastoderma glaucum (Bivalvia) from Baltic and Mediterranean populations

Chromosomes of C. glaucum from Baltic (Gdansk Bay) and Mediterranean (Thau lagoon, Sète) populations were studied using karyometric analysis and silver-staining. The karyotype of the Gdansk population consists of three metacentric, ten submetacentric and six subtelocentric chromosome pairs. The karyotype of the Thau population shows four metacentric, nine submetacentric and six subtelocentric pairs. Nucleolus organizer regions were found terminally on the second largest submetacentric chromosome pair of the Gdansk population and on the second largest metacentric chromosome pair of the Thau population. This suggests a cytotaxomomic difference between these two geographically isolated populations. Striking differences exist between C. glaucum and C. edule karyotypes, probably resulting from a long divergence time.     

Speciation via hybrid dysgenesis: negative evidence from the Drosophila affinis subgroup

Differences in karyotypic structure are compared with reported isozyme differences in three Mediterranean species of Patella. In addition, the karyotypic structure of Patella is discussed in terms of the karyotypic variability of Archaeogastropoda. Both P. lusitanica and P. caerulea have a haploid complement of n=9 (6 metacentric, 1 submetacentric, 1 subtelocentric, 1 telocentric chromosome in P. lusitanica and 6 metacentric, 1 submetacentric, 2 telocentric chromosome in P. caerulea). P. aspera, although regarded as morphologically more closely related to P. caerulea, has a haploid complement of only n=8 (7 metacentric and 1 submetacentric chromosomes).     

蝙蝠科七种蝙蝠的核型

报道了贵州7 种蝙蝠科蝙蝠的核型。伏翼和印度伏翼的染色体数为2n = 26 , 常染色体都由10 对双臂染色体和2 对微小点状染色体组成, N.F = 44 , 性染色体是大小悬殊的端着丝粒染色体; 两者核型的主要区别在于前者的No.3 是中着丝粒染色体, 后者为亚中着丝粒染色体; 大鼠耳辐(四川亚种) 、水鼠耳蝠和西南鼠耳蝠的染色体数都是2n = 44 , 常染色体都由4 对中着丝粒染色体和17 对端着丝粒染色体组成, N.F = 50 , 其中大鼠耳蝠(四川亚种) 和水鼠耳蝠核型非常相似, 西南鼠耳蝠与前二者有一定区别; 山蝠(福建亚种) 是2n = 36 , 常染色体包括7 对中着丝粒染色体、1 对亚中着丝粒染色体和9 对端着丝粒染色体, N.F = 50 ; 南蝠2n = 50 , 常染色体由24 对端着丝粒染色体组成, N.F = 48 , X染色体是最大的中着丝粒染色体。     

Cytogenetic characterisation of the Caspian Pond Turtle,Mauremys caspica in Golestan and Mazandaran provinces,Iran (Reptilia: Testudines)

Cytogenetic characteristics of the Caspian Pond Turtle, Mauremys caspica, in Golestan and Mazandaran provinces in the northern part of Iran show that the chromosome number is 2n?=?52 and the arm number NF?=?78. The karyotype consisted of 9 metacentric (M), 1 submetacentric (SM), 3 subtelocentric (ST) and 13 telocentric (T) chromosome pairs. The Centromeric Index ranges from 11.79 to 45.68, the arm ratio between 1.18 and 7.47, the relative length between 1.60 and 11.46, and the length variation between 1.05 and 7.48. Average total length of the chromosomes is 65.27 µm. The largest chromosome in this species is a pair of the metacentric chromosome. Location of NOR was determined on chromosome pair no. 10.     

Cytogenetic characterisation of the razor shells Ensis directus (Conrad, 1843) and E. minor (Chenu, 1843) (Mollusca: Bivalvia)

The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric–submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric–submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) _n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua.     

Karyotypes of some species of the genus Lessingianthus (Vernonieae,Asteraceae) and taxonomic implications

We determined the karyotypes of nine species of Lessingianthus, eight of which are here analyzed for the first time. The results include the first chromosome count for L. plantaginoides, which is tetraploid with 2n = 64. All species showed a high proportion of metacentric chromosomes combined with a lower proportion of submetacentric pairs. Only L. coriaceus had a subtelocentric chromosome pair. B chromosomes were observed in L. coriaceus and L. varroniifolius, which were subtelocentric. Differences among the karyotypes of the studied species were small, suggesting that karyotype diversity in the genus evolved by small changes in the structure of chromosomes. Karyotype features appear useful to distinguish Lessingianthus from the closely related genera Chrysolaena and Lepidaploa.     

Chromosomal description of the rodent generaOecomys andNectomys from Brazil

We analysed karyotypes of five taxa of the rodent generaOecomys andNectomys, trapped in 14 localities in an area ranging from 8° to 29°S on Brazilian territory.Oecomys cf.concolor, collected in the Amazon and in two localities of the Cerrado biome, showed a 2n=60 karyotype constituted by a pair of large subtelocentric chromosomes, a small metacentric pair and 27 acrocentric pairs. The X chromosome was a large submetacentric and a subtelo-submetacentric, the morphology of the latter showing variable C-banding patterns. In all three localities the Y chromosome was a medium size heterochromatic acrocentric. Two individuals from the Cerrado had a heterochromatic acrocentric B-chromosome.Oecomys cf.bicolor presented two cytotypes, 2n=80 in the specimens from the Cerrado biome and 2n=82 in individuals trapped in the Amazon. The 2n=80 cytotype 1 showed a large subtelocentric, 22 biarmed pairs (medium to small) and 16 acrocentric autosomal pairs. The karyotype of the 2n=82 cytotype 2 is constituted by 15 biarmed chromosomes (median to small) and 25 acrocentric pairs with heterochromatic blocks at pericentromeric regions. The sexual pairs were the same (large submetacentric X and median acrocentric Y) in both cytotypes. InO. cf.concolor and in both cytotypes ofO. cf.bicolor the nucleolar organizer regions were observed in 1-3 pairs, located in the short arms.Nectomys genus presented two cytotypes, 2n=52–55 (N. rattus, with 0–3 biarmed heterochromatic accessory chromosomes) and 2n=56–59 (N. squamipes, bearing 0–3 biarmed, heterochromatic, B-chromosomes). These 2 cytotypes occupy disjunct regions of South America, with overlapping areas in the Brazilian states of Pernambuco, Bahia, and Mato Grosso do Sul.     

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 Syrphidae. VI. The tribe Pipizini

The karyotypes of 24 species of the tribe Pipisini (Diptera: Syrphidae) are described and illustrated. Nearly all the species of Neocnemodon, Pipiza and Pipizella have 2n=8 chromosomes consisting of a short telocentric XY pair and three metacentric pairs increasing in relative length from long to very long. Pair II chromosomes in several Pipiza species have high metacentric to low submetacentric arm ratios. One Parapenium species is tentatively reported as having five pairs and another five or six pairs. The karyological evidence favours placing the tribe Pipizini in the subfamily Syrphinae rather than in the subfamily Milesiinae.     

Chromosomal polymorphism in Rattus rattus (L.) collected in Kusudomari and Misima

Summary Chromosomes of Rattus rattus (L.), collected in Kusudomari (Nagasaki) and Misima (Sizuoka) were examined. The karyotype revealed a remarkable heteromorphism in chromosome no. 1. The homozygotic, i.e. standard type, was characterized by 13 pairs of telocentric and 7 pairs of metacentric chromosomes. Chromosome pair no. 1 was telocentric. X and Y chromosomes were also telocentrics. 18.4 per cent of rats from Kusudomari and 40 per cent from Misima showed heteromorphic pair in chromosome no. 1. One chromosome of the heteromorphic pair is conspicuous by the subtelocentric centromere. Total length of the telocentric chromosome of no. 1 is almost the same as of its subtelocentric partner. These facts indicate that the subtelocentric no. 1 chromosome might have arisen by a centromeric inversion of the telocentric chromosome. Individuals homozygous for the subtelocentric no. 1 chromosome could not be found in either population. The difference in the frequency of the dimorphics collected in Kusudomari and Misima was statistically significant. Possible causes of the difference are discussed.Dedicated to Professor H. Bauer on the occasion of his sixtieth birthday. — Contributions from the National Institute of Genetics, Misima, Japan, No. 533     

Comparative cytogenetics of the African elephant (Loxodonta africana) and Asiatic elephant (Elephas maximus)

G- and C-banded karyotypes of the two extant species of the mammalian order Proboscidea are presented for the first time. Chromosome complements were 2n = 56 in both Loxodonta africana and Elephas maximus. Comparisons between the species demonstrated a high level of chromosome band homology, with 26 conserved autosomal pairs. The normal diploid karyotype of L. africana had 25 acrocentric/telocentric and two metacentric/submetacentric autosomal pairs. E. maximus differed by having one less acrocentric and one additional submetacentric pair due to either a heterochromatic arm addition or deletion involving autosomal pair 27. Several acrocentric autosomes of L. africana exhibited small short arms that were absent in homologous chromosomes of E. maximus. The X chromosomes in both species were large submetacentric elements and were homologous. However, the small acrocentric Y chromosomes differed; in E. maximus it was slightly larger and had more distinct G-bands than its counterpart in L. africana. Extant Elephantidae appear to be relatively conservative in their rates of chromosomal change compared to some other mammalian families. The high-quality banded karyotypes presented here should prove useful as references in future chromosome analyses of elephant populations and in comparative cytogenetic studies with other ungulate orders.     

Karyological Studies of Biomphalaria tenagophila (d'Orbigny, 1835) (Gastropoda: Planobidae) from Rio de Janeiro,Brazil

The karyotypes of Biomphalaria tenagophila collected from Rio de Janeiro, Brazil were studied using the air-drying method. Somatic cells of this species had 2n=36. The 18 chromosome pairs were identified and classified into 3 groups. The diploid cell has 7 pairs of metacentric, 8 pairs of submetacentric, and 3 pairs of subtelocentric chromosomes. Observed chromosomes ranged from 2.4 to 6.4 µm, and the total length was 122.3 µm. This is the first report on the chromosome of B. tenagophila.     

臭鼩染色体的研究

本文采用骨髓染色体制片法,对捕自我国浙江萧山市的臭鼩进行了组型、G-带、C-带和核仁组织区银染的观察分析。结果表明,我国臭鼩染色体数目为2n=40,组型为8(m)+2(sm)+10(st)+18(t),性染色体为,(?):X(m或sm),Y(m或sm);♀:XX(m或sm)。G-带较为丰富,每一对染色体都有其特定的带型,较易于辨别与配对。在C-带方前,4对中间着丝粒染色体与5对亚端着丝粒染色体均具有不同程度的着丝粒带,1对亚中着丝粒染色体与9对端着丝粒染色体缺乏C-带物质,性染色体具丰富的远端带及中间带.银染的结果显示,第5、12和13对染色体具银染物质。