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1.
Kornsorn Srikulnath Yoshinobu Uno Chizuko Nishida Yoichi Matsuda 《Chromosome research》2013,21(8):805-819
The water monitor lizard (Varanus salvator macromaculatus (VSA), Platynota) has a chromosome number of 2n?=?40: its karyotype consists of 16 macrochromosomes and 24 microchromosomes. To delineate the process of karyotype evolution in V. salvator macromaculatus, we constructed a cytogenetic map with 86 functional genes and compared it with those of the butterfly lizard (Leiolepis reevesii rubritaeniata (LRE); 2n?=?36) and Japanese four-striped rat snake (Elaphe quadrivirgata (EQU); 2n?=?36), members of the Toxicofera clade. The syntenies and gene orders of macrochromosomes were highly conserved between these species except for several chromosomal rearrangements: eight pairs of VSA macrochromosomes and/or chromosome arms exhibited homology with six pairs of LRE macrochromosomes and eight pairs of EQU macrochromosomes. Furthermore, the genes mapped to microchromosomes of three species were all located on chicken microchromosomes or chromosome 4p. No reciprocal translocations were found in the species, and their karyotypic differences were caused by: low frequencies of interchromosomal rearrangements, such as tandem fusions, or centric fissions/fusions between macrochromosomes and between macro- and microchromosomes; and intrachromosomal rearrangements, such as paracentric inversions or centromere repositioning. The chromosomal rearrangements that occurred in macrochromosomes of the Varanus lineage were also identified through comparative cytogenetic mapping of V. salvator macromaculatus and V. exanthematicus. Morphologic differences in chromosomes 6–8 between the two species could have resulted from pericentric inversion or centromere repositioning. 相似文献
2.
Concetta?Federico Catia?Daniela?Cantarella Cinzia?Scavo Salvatore?Saccone Bertrand?Bed'Hom Giorgio?Bernardi
The chicken karyotype, like that of the vast majority of avian species, shows a large number of dot-shaped microchromosomes
that are characterized, like most telomeric regions of the macrochromosomes, by the highest GC levels and the highest gene
densities. In interphase nuclei, these gene-dense regions are centrally located, and are characterized by an open chromatin
structure (a similar situation also exists in mammals). Avian species belonging to the Accipitridae family (diurnal raptors)
show a karyotype with no very large chromosomes, and with only a very small number of microchromosomes. To identify the GC-rich
(and gene-rich) regions of the chromosomes and nuclei from Accipitridae, we performed heterologous in-situ hybridizations using chicken GC-richest isochores as probes. Our results clearly show that the gene-rich regions are prevalently
located in the few microchromosome pairs and in the telomeric regions of the middle-sized chromosomes, as well as in the interior
of the interphase nuclei. This result is consistent with a common organization of the genome in the nuclei of warm-blooded
vertebrates. Indeed, in spite of the different size and morphology of the chromosomes, the gene-dense regions are always located
in the interior of the nuclei. 相似文献
3.
We have tested the tandem fusion hypothesis of the origin of the Indian muntjac karyotype (2n=6/7) by using reciprocal chromosome painting between the Indian muntjac, Chinese muntjac (n=46) and brown brocket deer (2n=70+3B)with chromosome-specific paint probes derived from flow-sorted chromosomes of these three deer species. Our results have shown that the euchromatic blocks of all chromosome arms of the brown brocket deer have been conserved apparently unchanged in number and content in the Indian muntjac. While confirming the conservation in toto of most of Chinese muntjac euchromatin in the karyotype of the Indian muntjac, we demonstrate that the synteny of chromosomes 1, 2, 3, 4 and 5 of the Chinese muntjac has been disrupted by chromosome rearrangements other than fusions. This indicates that the present karyotype of the Indian muntjac cannot be reconstructed from the hypothetical Chinese muntjac-like 2n=46 ancestral karyotype exclusively by chromosome fusions. Furthermore, we have shown that the breakpoints of these rearrangements appear to have occurred near to the fusion points formed during the origin of the 2n=46 karyotype of the Chinese muntjac from a 2n=70 karyotype, which is believed to be ancestral for the family Cervidae. Moreover, we substantiate that on the Indian muntjac chromosomes, the C5 probe, which is derived from the centromeric satellite sequences of the Chinese muntjac, maps to the putative fusion points determined by comparative chromosome painting and presumably represents the remnants of ancestral centromeric sequences.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
4.
Gaetano Odierna Gennaro Aprea Marco Barucca Maria Assunta Biscotti Adriana Canapa Teresa Capriglione Ettore Olmo 《Chromosome research》2008,16(6):899-906
We describe the karyotype, location of nucleolus-organizing regions (NORs) and heterochromatin distribution and composition in the Antarctic chiton Nuttallochiton mirandus. Specimens had a karyotype of 2n = 32 chromosomes, of which two were microchromosomes. Among macrochromosomes, the elements of the first and fourth pair were bi-armed, the others were telocentric. At least six NOR sites were detected with NOR-FISH, but only four were Ag-NOR-banding-positive. The two microchromosomes were essentially euchromatic, while all macrochromosomes exhibited clear pericentromeric C bands that were found to be AT-rich (being quinacrine- and DAPI-positive) and resistant to digestion with AluI and HaeIII. N. mirandus has the largest number of chromosomes (2n = 32) and telocentric elements (26) of all the chiton species studied to date. The karyological results of our study agree with previous molecular data indicating N. mirandus as a sister taxon of Acanthochitona crinita. The karyotypes of the two species could be related as a result of Robertsonian rearrangements. According to the more parsimonious hypothesis, the former would be the primitive karyotype, although other evolutionary events cannot be ruled out. 相似文献
5.
Edivaldo H. Correa de Oliveira Marcella M. Tagliarini Jorge Dores Rissino Julio C. Pieczarka Cleusa Y. Nagamachi Patricia C. M. O’Brien Malcolm A. Ferguson-Smith 《Chromosome research》2010,18(3):349-355
Evolutionary cytogenetics can take confidence from methodological and analytical advances that promise to speed up data acquisition
and analysis. Drastic chromosomal reshuffling has been documented in birds of prey by FISH. However, the available probes,
derived from chicken, have the limitation of not being capable of determining if breakpoints are similar in different species:
possible synapomorphies are based on the number of segments hybridized by each of chicken chromosome probes. Hence, we employed
FACS to construct chromosome paint sets of the white hawk (Leucopternis albicollis), a Neotropical species of Accipitridae with 2n = 66. FISH experiments enabled us to assign subchromosomal homologies between
chicken and white hawk. In agreement with previous reports, we found the occurrence of fusions involving segments homologous
to chicken microchromosomes and macrochromosomes. The use of these probes in other birds of prey can identify important chromosomal
synapomorphies and clarify the phylogenetic position of different groups of Accipitridae. 相似文献
6.
Svetlana Derjusheva Anna Kurganova Felix Habermann Elena Gaginskaya 《Chromosome research》2004,12(7):715-723
Chicken chromosome paints for macrochromosomes 1-10, Z, and the nine largest microchromosomes (Griffin et al. 1999) were used to analyze chromosome homologies between chicken (Gallus gallus domesticus: Galliformes), domestic pigeon (Columba livia: Columbiformes), chaffinch (Fringilla coelebs Passeriformes), and redwing (Turdus iliacus: Passeriformes). High conservation of syntenies was revealed. In general, both macro- and microchromosomes in these birds showed very low levels of interchromosomal rearrangements. Only two cases of rearrangements were found. Chicken chromosome 1 corresponds to chromosome 1 in pigeon, but to chromosomes 3 and 4 in chaffinch and chromosomes 2 and 5 in redwing. Chicken chromosome 4 was shown to be homologous to two pairs of chromosomes in the karyotypes of pigeon and both passerine species. Comparative analysis of chromosome painting data and the results of FISH with (TTAGGG)n probe did not reveal any correlation between the distribution of interstitial telomere sites (ITSs) and chromosome rearrangements in pigeon, chaffinch and redwing. In chaffinch, ITSs were found to co-localize with a tandem repeat GS (Liangouzov et al. 2002), monomers of which contain an internal TTAGGG motif. 相似文献
7.
Kornsorn Srikulnath Chizuko Nishida Kazumi Matsubara Yoshinobu Uno Amara Thongpan Saowanee Suputtitada Somsak Apisitwanich Yoichi Matsuda 《Chromosome research》2009,17(8):975-986
The butterfly lizard (Leiolepis reevesii rubritaeniata) has the diploid chromosome number of 2n = 36, comprising two distinctive components, macrochromosomes and microchromosomes. To clarify the conserved linkage homology
between lizard and snake chromosomes and to delineate the process of karyotypic evolution in Squamata, we constructed a cytogenetic
map of L. reevesii rubritaeniata with 54 functional genes and compared it with that of the Japanese four-striped rat snake (E. quadrivirgata, 2n = 36). Six pairs of the lizard macrochromosomes were homologous to eight pairs of the snake macrochromosomes. The lizard
chromosomes 1, 2, 4, and 6 corresponded to the snake chromosomes 1, 2, 3, and Z, respectively. LRE3p and LRE3q showed the
homology with EQU5 and EQU4, respectively, and LRE5p and LRE5q corresponded to EQU7 and EQU6, respectively. These results
suggest that the genetic linkages have been highly conserved between the two species and that their karyotypic difference
might be caused by the telomere-to-telomere fusion events followed by inactivation of one of two centromeres on the derived
dicentric chromosomes in the lineage of L. reevesii rubritaeniata or the centric fission events of the bi-armed macrochromosomes and subsequent centromere repositioning in the lineage of
E. quadrivirgata. The homology with L. reevesii rubritaeniata microchromosomes were also identified in the distal regions of EQU1p and 1q, indicating the occurrence of telomere-to-telomere
fusions of microchromosomes to the p and q arms of EQU1. 相似文献
8.
Wenhui Nie Jinhuan Wang Patricia C.M. O'Brien Beiyuan Fu Tian Ying Malcolm A. Ferguson-Smith Fengtang Yang 《Chromosome research》2002,10(3):209-222
Genome-wide homology maps among stone marten (Martes foina, 2n = 38), domestic cat (Felis catus, 2n = 38), American mink (Mustela vison, 2n = 30), yellow-throated marten (Martes flavigula, 2n = 40), Old World badger (Meles meles, 2n = 44), ferret badger (Melogale moschata, 2n = 38) and red panda (Ailurus fulgens, 2n = 36) have been established by cross-species chromosome painting with a complete set of stone marten probes. In total, 18 stone marten autosomal probes reveal 20, 19, 21, 18 and 21 pairs of homologous chromosomal segments in the respective genomes of American mink, yellow-throated marten, Old World badger, ferret badger and red panda. Reciprocal painting between stone marten and cat delineated 21 pairs of homologous segments shared in both stone marten and cat genomes. The chromosomal painting results indicate that most chromosomes of these species are highly conserved and show one-to-one correspondence with stone marten and cat chromosomes or chromosomal arms, and that only a few interchromosomal rearrangements (Robertsonian fusions and fissions) have occurred during species radiation. By comparing the distribution patterns of conserved chromosomal segments in both these species and the putative ancestral carnivore karyotype, we have reconstructed the pathway of karyotype evolution of these species from the putative 2n = 42 ancestral carnivore karyotype. Our results support a close phylogenetic relationship between the red panda and mustelids. The homology data presented in these maps will allow us to transfer the cat gene mapping data to other unmapped carnivore species. 相似文献
9.
10.
Wenhui Nie Patricia C. M. O’Brien Bee L. Ng Beiyuan Fu Vitaly Volobouev Nigel P. Carter Malcolm A. Ferguson-Smith Fengtang Yang 《Chromosome research》2009,17(1):99-113
The chicken is the most extensively studied species in birds and thus constitutes an ideal reference for comparative genomics
in birds. Comparative cytogenetic studies indicate that the chicken has retained many chromosome characters of the ancestral
avian karyotype. The homology between chicken macrochromosomes (1–9 and Z) and their counterparts in more than 40 avian species
of 10 different orders has been established by chromosome painting. However, the avian homologues of chicken microchromosomes
remain to be defined. Moreover, no reciprocal chromosome painting in birds has been performed due to the lack of chromosome-specific
probes from other avian species. Here we have generated a set of chromosome-specific paints using flow cytometry that cover
the whole genome of the stone curlew (Burhinus oedicnemus, Charadriiformes), a species with one of the lowest diploid number so far reported in birds, as well as paints from more
microchromosomes of the chicken. A genome-wide comparative map between the chicken and the stone curlew has been constructed
for the first time based on reciprocal chromosome painting. The results indicate that extensive chromosome fusions underlie
the sharp decrease in the diploid number in the stone curlew. To a lesser extent, chromosome fissions and inversions occurred
also during the evolution of the stone curlew. It is anticipated that this complete set of chromosome painting probes from
the first Neoaves species will become an invaluable tool for avian comparative cytogenetics. 相似文献
11.
Taiki Kawagoshi Chizuko Nishida Hidetoshi Ota Yoshinori Kumazawa Hideki Endo Yoichi Matsuda 《Chromosome research》2008,16(8):1119-1132
Crocodilians have several unique karyotypic features, such as small diploid chromosome numbers (30–42) and the absence of
dot-shaped microchromosomes. Of the extant crocodilian species, the Siamese crocodile (Crocodylus siamensis) has no more than 2n = 30, comprising mostly bi-armed chromosomes with large centromeric heterochromatin blocks. To investigate
the molecular structures of C-heterochromatin and genomic compartmentalization in the karyotype, characterized by the disappearance
of tiny microchromosomes and reduced chromosome number, we performed molecular cloning of centromeric repetitive sequences
and chromosome mapping of the 18S-28S rDNA and telomeric (TTAGGG)
n
sequences. The centromeric heterochromatin was composed mainly of two repetitive sequence families whose characteristics
were quite different. Two types of GC-rich CSI-HindIII family sequences, the 305 bp CSI-HindIII-S (G+C content, 61.3%) and 424 bp CSI-HindIII-M (63.1%), were localized to the intensely PI-stained centric regions of all chromosomes, except for chromosome 2 with
PI-negative heterochromatin. The 94 bp CSI-DraI (G+C content, 48.9%) was tandem-arrayed satellite DNA and localized to chromosome 2 and four pairs of small-sized chromosomes.
The chromosomal size-dependent genomic compartmentalization that is supposedly unique to the Archosauromorpha was probably
lost in the crocodilian lineage with the disappearance of microchromosomes followed by the homogenization of centromeric repetitive
sequences between chromosomes, except for chromosome 2. 相似文献
12.
Satoshi Ishishita Yuri Tsuruta Yoshinobu Uno Atsushi Nakamura Chizuko Nishida Darren K. Griffin Masaoki Tsudzuki Tamao Ono Yoichi Matsuda 《Chromosome research》2014,22(1):15-34
Many families of centromeric repetitive DNA sequences isolated from Struthioniformes, Galliformes, Falconiformes, and Passeriformes are localized primarily to microchromosomes. However, it is unclear whether chromosome size-correlated homogenization is a common characteristic of centromeric repetitive sequences in Aves. New World and Old World quails have the typical avian karyotype comprising chromosomes of two distinct sizes, and C-positive heterochromatin is distributed in centromeric regions of most autosomes and the whole W chromosome. We isolated six types of centromeric repetitive sequences from three New World quail species (Colinus virginianus, CVI; Callipepla californica, CCA; and Callipepla squamata, CSQ; Odontophoridae) and one Old World quail species (Alectoris chukar, ACH; Phasianidae), and characterized the sequences by nucleotide sequencing, chromosome in situ hybridization, and filter hybridization. The 385-bp CVI-MspI, 591-bp CCA-BamHI, 582-bp CSQ-BamHI, and 366-bp ACH-Sau3AI fragments exhibited tandem arrays of the monomer unit, and the 224-bp CVI-HaeIII and 135-bp CCA-HaeIII fragments were composed of minisatellite-like and microsatellite-like repeats, respectively. ACH-Sau3AI was a homolog of the chicken nuclear membrane repeat sequence, whose homologs are common in Phasianidae. CVI-MspI, CCA-BamHI, and CSQ-BamHI showed high homology and were specific to the Odontophoridae. CVI-MspI was localized to microchromosomes, whereas CVI-HaeIII, CCA-BamHI, and CSQ-BamHI were mapped to almost all chromosomes. CCA-HaeIII was localized to five pairs of macrochromosomes and most microchromosomes. ACH-Sau3AI was distributed in three pairs of macrochromosomes and all microchromosomes. Centromeric repetitive sequences may be homogenized in chromosome size-correlated and -uncorrelated manners in New World quails, although there may be a mechanism that causes homogenization of centromeric repetitive sequences primarily between microchromosomes, which is commonly observed in phasianid birds. 相似文献
13.
To understand the cytogenetic characteristics of acute fibrosarcoma in chickens infected with the subgroup J avian leukosis virus associated with the v-src oncogene, we performed a karyotype analysis of fibrosarcoma cell cultures. Twenty-nine of 50 qualified cell culture spreads demonstrated polyploidy of some macrochromosomes, 21 of which were trisomic for chromosome 7, and others were trisomic for chromosomes 3, 4, 5 (sex chromosome w), and 10. In addition, one of them was trisomic for both chromosome 7 and the sex chromosome 5 (w). In contrast, no aneuploidy was found for 10 macrochromosomes of 12 spreads of normal chicken embryo fibroblast cells, although aneuploidy for some microchromosomes was demonstrated in five of the 12 spreads. The cytogenetic mosaicism or polymorphism of the aneuploidy in the acute fibrosarcoma described in this study suggests that the analysed cells are polyclonal. 相似文献
14.
Bruce?S.?Milne Tess?Hoather Patricia?C.M.?O’Brien Fengtang?Yang Malcolm?A.?Ferguson-Smith Jane?Dobson David?Sargan
Many canine tumour types represent useful models for tumours also found in humans. Studies of chromosomal abnormalities in
canine tumours have been impeded by the complexity of the canine karyotype (2n = 78), which has made accurate identification
of rearranged chromosomes difficult and laborious. To overcome this difficulty we have developed a seven-colour paint system
for canine chromosomes, with six sets of chromosome paints covering all chromosomes except Y. Several pairs of canine autosomes
co-locate in the flow karyotype. To distinguish these autosomes from each other, paint sets were supplemented with chromosomes
of red fox and Japanese raccoon dog. Paints were used in fluorescence in-situ hybridization to analyse karyotypes in fourteen canine soft tissue sarcomas. Rearranged karyotypes were observed in seven
tumours, but there was evidence for loss of rearrangement during tissue culture. Five tumours had rearrangements involving
four chromosomes or fewer; one, a chondrosarcoma, had lost seven chromosomes whilst the last, a spindle cell sarcoma, had
rearrangements involving eighteen chromosome pairs. The paint sets described here facilitate the complete cytogenetic analysis
of balanced translocations and other inter-chromosomal rearrangements in canine tumours. We believe that this is the first
canine tumour series to be subjected to this level of analysis. 相似文献
15.
Comparison of the chicken and turkey genomes reveals a higher rate of nucleotide divergence on microchromosomes than macrochromosomes 总被引:8,自引:1,他引:7
A distinctive feature of the avian genome is the large heterogeneity in the size of chromosomes, which are usually classified into a small number of macrochromosomes and numerous microchromosomes. These chromosome classes show characteristic differences in a number of interrelated features that could potentially affect the rate of sequence evolution, such as GC content, gene density, and recombination rate. We studied the effects of these factors by analyzing patterns of nucleotide substitution in two sets of chicken-turkey sequence alignments. First, in a set of 67 orthologous introns, divergence was significantly higher in microchromosomes (chromosomes 11-38; 11.7% divergence) than in both macrochromosomes (chromosomes 1-5; 9.9% divergence; P = 0.016) and intermediate-sized chromosomes (chromosomes 6-10; 9.5% divergence; P = 0.026). At least part of this difference was due to the higher incidence of CpG sites on microchromosomes. Second, using 155 orthologous coding sequences we noted a similar pattern, in which synonymous substitution rates on microchromosomes (13.1%) were significantly higher than were rates on macrochromosomes (10.3%; P = 0.024). Broadly assuming neutrality of introns and synonymous sites, or constraints on such sequences do not differ between chromosomal classes, these observations imply that microchromosomal genes are exposed to more germ line mutations than those on other chromosomes. We also find that dN/dS ratios for genes located on microchromosomes (average, 0.094) are significantly lower than those of macrochromosomes (average, 0.185; P = 0.025), suggesting that the proteins of genes on microchromosomes are under greater evolutionary constraint. 相似文献
16.
Jose C. Mota-Velasco Irani Alves Ferreira Marcelo B. Cioffi Konrad Ocalewicz Rafael Campos-Ramos Andrey Shirak Bo-Young Lee Cesar Martins David J. Penman 《Chromosome research》2010,18(5):575-586
Oreochromis karongae, one of the “chambo” tilapia species from Lake Malawi, has a karyotype of 2n = 38, making it one of the few species investigated to differ from the typical tilapia karyotype (2n = 44). The O. karongae karyotype consists of one large subtelocentric pair of chromosomes, four medium-sized pairs (three subtelocentric and one
submetacentric) and 14 small pairs. The five largest pairs could be distinguished from each other on the basis of size, morphology
and a series of fluorescence in situ hybridisation (FISH) probes. The largest pair is easily distinguished on the basis of
size and a chromosome 1 (linkage group 3) bacterial artificial chromosome (BAC) FISH probe from Oreochromis niloticus. BAC clones from O. niloticus chromosome 2 (linkage group 7) hybridised to one of the medium-sized subtelocentric chromosome pairs (no. 5) of O. karongae, distinguishing the ancestral medium-sized pair from the three other medium-sized chromosome pairs (nos. 2, 3 and 4) that
appear to have resulted from fusions. SATA repetitive DNA hybridised to the centromeres of all 19 chromosome pairs and also
revealed the locations of the relic centromeres in the three fused pairs. Telomeric (TTAGGG)n repeats were identified in the telomeres of all chromosomes, and an interstitial telomeric site (ITS) was identified in three
chromosomal pairs (no. 2, 3 and 4). Additionally, two ITS sites were identified in the largest chromosome pair (pair 1), confirming
the origin of this chromosome from three ancestral chromosomes. SATA and ITS sites allowed the orientation of the fusions
in pairs 2, 3 and 4, which all appear to have been in different orientations (q–q, p–q and p–p, respectively). One of these
fusions (O. karongae chromosome pair no. 2) involves a small chromosome (equivalent to linkage group 1), which in O. niloticus carries the main sex-determining gene. 4′,6-Diamidino-2-phenyloindole staining of the synaptonemal complex in male O. karongae revealed the presumptive positions of the kinetochores, which correspond well to the centromeric positions observed in the
mitotic karyotype. 相似文献
17.
Chizuko Nishida-Umehara Yayoi Tsuda Junko Ishijima Junko Ando Atushi Fujiwara Yoichi Matsuda Darren K. Griffin 《Chromosome research》2007,15(6):721-734
Palaeognathous birds (Struthioniformes and Tinamiformes) have morphologically conserved karyotypes and less differentiated
ZW sex chromosomes. To delineate interspecific chromosome orthologies in palaeognathous birds we conducted comparative chromosome
painting with chicken (Gallus gallus, GGA) chromosome 1–9 and Z chromosome paints (GGA1–9 and GGAZ) for emu, double-wattled cassowary, ostrich, greater rhea,
lesser rhea and elegant crested tinamou. All six species showed the same painting patterns: each probe was hybridized to a
single pair of chromosomes with the exception that the GGA4 was hybridized to the fourth largest chromosome and a single pair
of microchromosomes. The GGAZ was also hybridized to the entire region of the W chromosome, indicating that extensive homology
remains between the Z and W chromosomes on the molecular level. Comparative FISH mapping of four Z- and/or W-linked markers,
the ACO1/IREBP, ZOV3 and CHD1 genes and the EE0.6 sequence, revealed the presence of a small deletion in the proximal region of the long arm of the W chromosome
in greater rhea and lesser rhea. These results suggest that the karyotypes and sex chromosomes of palaeognathous birds are
highly conserved not only morphologically, but also at the molecular level; moreover, palaeognathous birds appear to retain
the ancestral lineage of avian karyotypes. 相似文献
18.
The chromosomes of longnose gar, Lepisosteus osseus, an extant representative of early radiation of actinopterygian fishes, were studied using conventional Giemsa-staining, Ag-staining, CMA3-fluorescence and fluorescence in-situ hybridization (FISH). The diploid chromosome number was 2n = 56 and the karyotype contained 11 pairs of metacentric, 6 pairs of submetacentric, 3 pairs of subtelocentric macrochromosomes and 16 microchromosomes. Nearly all macrochromosomes showed large CMA3-positive regions resembling the R-bands of higher vertebrates, indicating extensive distribution of GC-rich DNA along chromosomes. The nucleolar organizer regions (NORs) were located on the end of the short arm of a single small metacentric macrochromosomal pair. These sites were strongly CMA3-positive, suggesting that ribosomal sites are associated with GC- rich DNA. In-situ hybridization (FISH) with a rDNA probe gave consistently positive signals in the same regions detected by Ag- staining and CMA3-fluorescence. The evolutionary conservation of positive CMA3-fluorescence of ribosomal sites in holostean and teleostean fishes is discussed. 相似文献
19.
We developed chromosome painting probes for Callicebus pallescens from flow-sorted chromosomes and used multidirectional chromosome painting to investigate the genomic rearrangements in C. cupreus and C. pallescens. Multidirectional painting provides information about chromosomal homologies at the subchromosomal level and rearrangement break points, allowing chromosomes to be used as cladistic markers. Chromosome paints of C. pallescens were hybridized to human metaphases and 43 signals were detected. Then, both human and C. pallescens probes were hybridized to the chromosomes of another titi monkey, C. cupreus. The human chromosome paints detected 45 segments in the haploid karyotype of C. cupreus. We found that all the syntenic associations proposed for the ancestral platyrrhine karyotype are present in C. cupreus and in C. pallescens. The rearrangements differentiating C. pallescens from C. cupreus re one inversion, one fission and three fusions (two tandem and one Robertsonian)that occurred on the C. cupreus lineage. Our results support the hypothesis that karyological evolution in titi monkeys has resulted in reduction in diploid number and that species with higher diploid numbers (with less derived, more ncestral karyotypes)are localized in the centre of the geographic range of the genera, while more derived species appear to occupy the periphery 相似文献
20.
Petra Musilova Svatava Kubickova Petr Horin Roman Vodi?ka Jiri Rubes 《Chromosome research》2009,17(6):783-790
Cross-species chromosome painting has been applied to most of the species making up the numerically small family Equidae.
However, comparative mapping data were still lacking in Asiatic asses kulan (Equus hemionus kulan) and kiang (E. kiang). The set of horse arm-specific probes generated by laser microdissection was hybridized onto kulan (E. hemionus kulan) and kiang (E. kiang) chromosomes in order to establish a genome-wide chromosomal correspondence between these Asiatic asses and the horse. Moreover,
region-specific probes were generated to determine fusion configuration and orientation of conserved syntenic blocks. The
kulan karyotype (2n = 54) was ascertained to be almost identical to the previously investigated karyotype of onager E. h. onager (2n = 56). The only difference is in fusion/fission of chromosomes homologous to horse 2q/3q, which are involved in chromosome
number polymorphism in many Equidae species. E. kiang karyotype differs from the karyotype of E. hemionus by two additional fusions 8q/15 and 7/25. Chromosomes equivalent to 2q and 3q are not fused in kiang individuals with 2n = 52.
Several discrepancies in centromere positions among kulan, kiang and horse chromosomes have been described. Most of the chromosome
fusions in Asiatic asses are of centromere–centromere type. Comparative chromosome painting in kiang completed the efforts
to establish chromosomal homologies in all representatives of the family Equidae. Application of region-specific probes allows
refinement comparative maps of Asiatic asses. 相似文献