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.     

马尾松染色体荧光带型的研究

对马尾松有丝分裂中期染色体荧光带纹的分析结果表明,其色霉素Ａ的染色体的荧光带赤;１对为着丝粒区和臂间我均有带纹的中间着丝染色体。６对为臂间区有带纺的中间着丝粒染色体;２对为着丝粒区有带纹的中间着丝粒染色体;３对无带纹的中间或近中着丝粒染色体;１对为着丝粒区有带纹的近中着丝粒染色体。     

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.     

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。     

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.     

白眉长臂猿(Hylobates hoolock leuconedys)的染色体研究

本文对两只雄性白眉长臂猿的染色体的C带、G带及Ag-NORs分布进行了较详细的分析,证实染色体数2n=38,并对该种的分类地位提出了一些新看法。     

Karyotypes of the most primitive catfishes (Teleostei: Siluriformas: Diplomystidae)

Karyotypes of Diplomystes composensis and Diplomystes nahuelbutaensis were the same diploid number (n= 56).The chromosome formula for D. composensis was 16 metacentric + 24 submetacentric + 8 subtelocentric + 8 telocentric chromosomes and for D. nahuelbutaensis was 14 metacentric + 26 submetacentric + 8 subtelocentric +8 telocentric chromosomes. In contrast, the differences in the chromosomal C-banding patterns between these species was large. For instance, chromosome pairs 5,6, and 7 of D. nahuelbutaensis showed heterochromatic centromeres and pairs 23, 24, 27, and 28 were entirely heterochromotic. Diplomystes composensis showed conspicuous C-banded blocks in pairs 7, 24, and 25 (chromosome pair 7 had one heterochromatic arm, chromosome pair 24 was entirely heterochromatic, and chromosome pair 25 had heterochromatin close to centromere). Comparison with other ostariophysan karyotypes (e.g. gymnotiforms, characiforms, and cypriniforms), does not allow any conclusions about the ploesiomorphic catfish condition, because the karyotypes of the outgroups are too variable. A synapomorphy shared by characiforms, gymnotiforms, and diplomystid catfishes is the presence of more metacentric to submetacentric than substelocentric to telocentric chromosomes. Cypriniforms are more primitive because they have more subtelocentric to telocentric than metacentric to submetacentric chromosomes.     

中国五台山多目涡虫(涡虫纲,三肠目)染色体及核型分析

利用空气干燥法对采自山西茶铺和镇海寺的五台山多目涡虫Polycelis wutaishanica Liu,1996的核型进行分析,结果表明:五台山多目涡虫体细胞有42条染色体,为2倍体,核型公式2n=2x=42 =28m 14sm,其中28条为中部着丝粒染色体, 14条为亚中部着丝粒染色体,第1对中部着丝粒染色体明显比其它染色体长。五台山多目涡虫的核型属于2C型。     

Chromosomal mapping of the major and minor ribosomal genes, (GATA)n and (TTAGGG)n by one-color and double-color FISH in the toadfish Halobatrachus didactylus (Teleostei: Batrachoididae)

The karyotype of Halobatrachus didactylus presents 46 chromosomes, composed of eight metacentric, 18 submetacentric, four subtelocentric, and 16 acrocentric chromosomes. The results of FISH showed that the major ribosomal genes were located in the terminal position of the short arm of a large submetacentric chromosome. They also showed a high variation in the hybridization signals. The products of amplification of 5S rDNA produced bands of about 420 pb. The PCR labeled products showed hybridization signals in the subcentromeric position of the long arm of a submetacentric chromosome of medium size. Double-color FISH indicated that the two ribosomal families are not co-located since they hybridizated in different chromosomal pairs. Telomeres of all the chromosomes hybridized with the (TTAGGG) _n probe. The GATA probe displayed a strong signal in the long arm of a submetacentric chromosome of medium size, in the subcentromeric position. The double-color FISH showed that the microsatellite GATA and the 5S rDNA gene are located in different chromosomal pairs. The majority presence of GATA probes in one pair of chromosomes is unusual and considering its distribution through different taxa it could be due to evolutionary mechanisms of heterochromatine accumulation, leading to the formation of differentiated sex chromosomes.     

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。       

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。     

铺道蚁的染色体核型分析

以商丘地区的铺道蚁Tetramorium caespitum(L.)早期胚胎为材料,采用低渗处理—烘干法制备染色体标本,对其染色体组型进行研究。结果表明,铺道蚁染色体组型为n=22,2n=44,是由10条中央着丝粒染色体,3条亚中着丝粒染色体和9条亚端着丝粒染色体组成。     

KARYOTYPES OF FIVE SUBANTARCTIC BIVALVE SPECIES

Chromosomes of five subantarctic species were studied from mitoticmetaphases using cell suspension techniques. Among the Protobranchia,Malletiagigan-lea has a diploid chromosome number of 2n = 38with five metacentric, seven submetacentric, five sub-telocentricand one telocentric pairs, and Yoldia (Aequiyoldia) woodwardialso shows 2n = 38 but with ten metacentric, six submetacentricand three sub-telocentric pairs. Among the Lamellibranchia,the pterioidan Limatula pygmaea has 2n = 38 with six metacentric,eleven submetacentric and two sub-telocentric pairs, the veneroidanCyclocardia astar-toides has 2n = 30 with five metacentric andten telocentric pairs and the anomalodesmatan Laternula ellipticahas 2n = 40 with two metacentric, one submetacentric, two subtelocentricand fifteen telocentric pairs. Our results indicate that in all the Nuculoidea studied so far,a diploid number of 2n = 38 has been found. In addition, thekaryotypes show a close overall appearance in relative lengthswith a majority of meta-centric-submetacentric chromosomes.The species differ in the proportion of the different morphologicaltypes of chromosomes. In the Lamellibranchia, each species correspondsto a particular case within their respective orders (Pterioida,Veneroida, Anomalodesmata). (Received 22 January 1990; accepted 28 March 1990)     

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.     

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.     

Molecular cytogenetic characterization of Ciona intestinalis chromosomes

The compact genome of the ascidian Ciona intestinalis has been sequenced. Chromosome karyotype and mapping of the genome sequence information on each of the 14 pairs of chromosomes are essential for genome-wide studies of gene expression and function in this basal chordate. Although the small chromosome size (most pairs measuring less than 2 mum) complicates accurate chromosome pairing based on morphology alone, the present results suggest that 20 chromosomes are metacentric and 8 are submetacentric or subtelocentric, and two pairs of large chromosomes (#1 and #2) were defined. The characterization of chromosomes by FISH and staining with propidium iodide indicated that 18S/28S ribosomal gene repeats are present in the short arms of three pairs of chromosomes and that the short arms of these pairs show remarkable size polymorphism. In addition, each chromosome was characterized molecular cytogenetically by mapping representative BAC clones with FISH. The present study is therefore a first step in expanding the karyotype analysis and entire physical mapping of the genome sequence of Ciona intestinalis.     

几种珍稀灵长类淋巴细胞系的建立和保存

本文介绍了用ＥＢＶ化建立的滇金丝猴、川金丝猴、白眉长臂猿、黑叶猴、灰叶猴、白臀叶猴、懒猴等珍稀灵长类的淋巴细胞系,并对携带病毒基因的Ｂ９５－８细胞的染色体作了详细分析。     

A note on chromosomes of two species of tree shrews (Tupaiidae)

Karyological studies of five tree shrews showed a diploid number 2n=60 forTupaia glis and 2n=66 forTupaia minor. The Y chromosome ofTupaia glis was found to be a medium-sized submetacentric chromosome in contrast to earlier data in the literature. The karyotype of a femaleTupaia minor showed five pairs of metacentric and submetacentric chromosomes and 28 pairs of acrocentric chromosomes.     

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.