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1.
Taro Nakamura Asato Kuroiwa Chizuko Nishida-Umehara Kazumi Matsubara Fumio Yamada Yoichi Matsuda 《Chromosome research》2007,15(6):799-806
Ryukyu spiny rats (genus Tokudaia) are indigenous species that are confined to three islands of the Nansei Shoto archipelago, Amami-Oshima, Tokunoshima and
Okinawa-jima, Japan. Tokudaia tokunoshimensis from Tokunoshima Island and Tokudaia osimensis from Amami-Oshima Island are closely related taxonomically, although their karyotypes are quite different: the diploid chromosome
numbers and sex chromosome constitution are 2n = 45, X0/X0 for T. tokunoshimensis and 2n = 25, X0/X0 for T. osimensis. We conducted comparative chromosome painting with chromosome-specific DNA probes of the laboratory mouse (Mus musculus) to molecularly examine the chromosome homology between T. tokunoshimensis and T. osimensis, and deduced a possible ancestral karyotype of Tokudaia species and the process of evolutionary chromosome rearrangements. The proposed ancestral karyotype with the diploid number
of 2n = 48, XX/XY was similar to the karyotype of T. tokunoshimensis, and the karyotype of T. osimensis would then have been established through at least 14 chromosomal changes, mainly centric fusion and tandem fusion, from the
ancestral karyotype. The close karyological relationship between the ancestral karyotypes of Tokudaia and Apodemus also suggests that the chromosomal evolution in the Tokudaia-Apodemus lineage has been very slow and has accelerated only recently in the branch leading to T. osimensis. 相似文献
2.
Tsuyoshi Kobayashi Fumio Yamada Takuma Hashimoto Shintaro Abe Yoichi Matsuda Asato Kuroiwa 《Chromosome research》2007,15(2):175-187
The Ryukyu spiny rats (genus Tokudaia) inhabit only three islands in the Nansei Shoto archipelago in Japan, and have the variations of karyotype among the islands.
The chromosome number of T. osimensis in Amami-Oshima Island is 2n = 25, and T. tokunoshimensis in Tokunoshima Island is 2n = 45, and the two species have X0 sex chromosome constitution with no cytogenetically visible
Y chromosome in both sexes. We constructed the standard ideograms for these species at the 100 and 200 band levels. Comparing
the banding patterns between these species, it was suggested that at least 10 times the number of Robertsonian fusions occurred
in T. osimensis chromosomes. However, no karyotypic differences were observed between sexes in each species. To detect the sex-specific chromosomal
region of these X0 species we applied the comparative genomic hybridization (CGH) method. Although the male- and female-derived
gains and losses were detected in several chromosome regions, all of them were located in the heterochromatic and/or telomeric
regions. This result suggested that the differences detected by CGH might be caused by the polymorphism on the copy numbers
of repeated sequences in the heterochromatic and telomeric regions. Our result indicated that the sex-specific region, where
the key to sex determination lies, is very minute in X0 species of Tokudaia. 相似文献
3.
Svetlana A. Romanenko Natalia A. Sitnikova Natalya A. Serdukova Polina L. Perelman Nadezhda V. Rubtsova Irina Yu. Bakloushinskaya Elena A. Lyapunova Walter Just Malcolm A. Ferguson-Smith Fengtang Yang Alexander S. Graphodatsky 《Chromosome research》2007,15(7):891-897
Using cross-species chromosome painting, we have carried out a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems: the Transcaucasian mole vole, Ellobius lutescens (2n = 17, X in both sexes), and the northern mole vole, Ellobius talpinus (2n = 54, XX in both sexes). Both Ellobius species have highly rearranged karyotypes. The chromosomal paints from the field vole (Microtus agrestis) detected, in total, 34 and 32 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. No difference in hybridization pattern of the X paint (as well as Y paint) probes on male and female
chromosomes was discovered. The set of golden hamster (Mesocricetus auratus) chromosomal painting probes revealed 44 and 43 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. A comparative chromosome map was established based on the results of cross-species chromosome painting
and a hypothetical ancestral Ellobius karyotype was reconstructed. A considerable number of rearrangements were detected; 31 and 7 fusion/fission rearrangements
differentiated the karyotypes of E. lutescens and E. talpinus from the ancestral Ellobius karyotype. It seems that inversions have played a minor role in the genome evolution of these Ellobius species. 相似文献
4.
Intragenomic chromosome homology in the B genome of Brassica
nigra and their homoeology with the chromosomes of the A-genome of B. rapa and C-genome of B. oleracea was investigated in triploids (ABC, n = 27) of different origins obtained following hybridizations between natural B.
napus (AACC, 2n = 38) × B. nigra (BB, 2n = 16) [AC.B], synthetic B. napus × B. nigra [A.C.B] and B. carinata (BBCC, 2n = 34) × B. rapa (AA, 2n = 20) [BC.A]. A relatively high percentage of pollen mother cells (PMCs) with at least one B-genome chromosome paired
allosyndetically with A/C chromosomes was evident in all three combinations. A maximum of three B-genome chromosomes undergoing
allosyndesis per cell was observed in AC.B and A.C.B combinations. A maximum of two autosyndetic bivalents within the B genome
appeared at diakinesis in all combinations. The accurate analyses of auto- and allo-syndetic pairing for B genome in trigenomic
combinations provided further evidence for the hypothesis that the three basic diploid genomes of the cultivated Brassica species evolved from one common ancestral genome with a lower chromosome number. The results showed that Brassica diploids may not be ancient polyploids but may have undergone chromosomal duplications instead of whole-genome duplication.
The relevance of these results along with genetic changes of progenitor genomes which occurred during the evolution of Brassica polyploids is discussed. 相似文献
5.
Ana Paula de Moraes Walter dos Santos Soares Filho Marcelo Guerra 《Chromosome research》2007,15(1):115-121
Grapefruit is a group of citrus of recent origin, probably resulting from a cross between pummelo and sweet-orange. Aiming
to investigate this putative origin and the genetic variability among grapefruit cultivars, the karyotype of six grapefruits,
two pummelos, and one tangelo cultivar (grapefruit × tangerine) were analyzed using sequential CMA/DAPI double staining and
FISH with rDNA probes. The karyotypes of grapefruit ‘Duncan’ and ‘Foster’ differ from those of ‘Flame’, ‘Henderson’, ‘Marsh’
and ‘Rio Red’. The former have two chromosomes with a single CMA+ band in both terminal regions (C type chromosome) and six chromosomes with only one CMA+ terminal band (D type), whereas the latter have three C and five D type chromosomes. All accessions investigated exhibited
two chromosomes with 5S rDNA but a variable number of 45S rDNA. The two former grapefruits displayed four 45S rDNA sites,
whereas the remaining grapefruit cultivars had five. The two pummelos showed identical karyotypes, homozygous for CMA+ bands and their four rDNA sites. From each pummelo chromosome pair one chromosome seems to be present in grapefruit karyotypes.
The different grapefruit karyotypes might result from independent crosses between pummelos of different karyotypic constitution
and sweet-oranges. The chromosome markers found in the tangelo ‘Orlando’ and the position of their two 45S rDNA confirm the
grapefruit ‘Duncan’ and the tangerine ‘Dancy’ as their parents. 相似文献
6.
Cross-species chromosome painting among camel, cattle, pig and human: further insights into the putative Cetartiodactyla ancestral karyotype 总被引:1,自引:0,他引:1
Gabriel Balmus Vladimir A. Trifonov Larisa S. Biltueva Patricia C.M. O’Brien Elena S. Alkalaeva Beiyuan Fu Julian A. Skidmore Twink Allen Alexander S. Graphodatsky Fengtang Yang Malcolm A. Ferguson-Smith 《Chromosome research》2007,15(4):499-514
The great karyotypic differences between camel, cattle and pig, three important domestic animals, have been a challenge for
comparative cytogenetic studies based on conventional cytogenetic approaches. To construct a genome-wide comparative chromosome
map among these artiodactyls, we made a set of chromosome painting probes from the dromedary camel (Camelus dromedarius) by flow sorting and degenerate oligonucleotide primed-PCR. The painting probes were first used to characterize the karyotypes
of the dromedary camel (C. dromedarius), the Bactrian camel (C. bactrianus), the guanaco (Lama guanicoe), the alpaca (L. pacos) and dromedary × guanaco hybrid karyotypes (all with 2n = 74). These FISH experiments enabled the establishment of a
high-resolution GTG-banded karyotype, together with chromosome nomenclature and idiogram for C. dromedarius, and revealed that these camelid species have almost identical karyotypes, with only slight variations in the amount and distribution
patterns of heterochromatin. Further cross-species chromosome painting between camel, cattle, pig and human with painting
probes from the camel and human led to the establishment of genome-wide comparative maps. Between human and camel, pig and
camel, and cattle and camel 47, 53 and 53 autosomal conserved segments were detected, respectively. Integrated analysis with
previously published comparative maps of human/pig/cattle enabled us to propose a Cetartiodactyla ancestral karyotype and
to discuss the early karyotype evolution of Cetartiodactyla. Furthermore, these maps will facilitate the positional cloning
of genes by aiding the cross-species transfer of mapping information.
†Both authors contributed equally to this paper. 相似文献
7.
Chromosomes of the invasive tapeworm Khawia sinensis (Caryophyllidea), the specific parasite of common carp, were analyzed by means of conventional Giemsa staining and using
fluorescent DAPI and YOYO-1 dyes, silver staining, and fluorescent in situ hybridization (FISH) with 18S rDNA probe. The karyotype
is composed of eight pairs of metacentric and telocentric chromosomes (2n = 16, n = 3m + 5t, TCL = 42.54 μm). Constitutive heterochromatin was located at pericentromeric regions of all pairs, except for the largest
metacentric pair (no. 1), which possessed no DAPI-positive band. FISH with rDNA probe revealed that both homologues of chromosome
pair no. 6 carry a cluster of ribosomal arrays, which were located interstitially close to the centromere. Present results
are compared with previous cytogenetic data on Khawia spp., and comments are made on the karyotypes with respect to their phylogenetic links. 相似文献
8.
C. Gilbert P. C. O’Brien G. Bronner F. Yang A. Hassanin M. A. Ferguson-Smith T. J. Robinson 《Chromosome research》2006,14(8):793-803
Golden moles (Chrysochloridae) are poorly known subterranean mammals endemic to Southern Africa that are part of the superordinal
clade Afrotheria. Using G-banding and chromosome painting we provide a comprehensive comparison of the karyotypes of five
species representing five of the nine recognized genera: Amblysomus hottentotus, Chrysochloris asiatica, Chrysospalax trevelyani, Cryptochloris zyli and Eremitalpa granti. The species are karyotypically highly conserved. In total, only four changes were detected among them. Eremitalpa granti has the most derived karyotype with 2n = 26 and differs from the remaining species (all of whom have 2n = 30) by one centric
and one telomere:telomere fusion. In addition, two intrachromosomal rearrangements were detected in A. hottentotus. The painting probes also suggest the presence of a unique satellite DNA family located on chromosomes 11 and 12 of both
C. asiatica and C. zyli. This represents a synapomorphy linking these two sympatric species as sister taxa. A molecular clock was calibrated adopting
a relaxed Bayesian approach for multigene data sets comprising publicly available sequences derived from five gene fragments
representative of three golden moles and 39 other eutherian species. The data suggest that golden moles diverged from a common
ancestor approximately 28.5 mya (95% credibility interval = 21.5–36.5 mya). Based on an inferred chrysochlorid ancestral karyotype
of 2n = 30, the estimated rate of 0.7 rearrangements per 10 my (95% Credibility Interval = 0.54–0.93) differs from the ‘default
rate’ of mammalian chromosomal evolution which has been estimated at one change per 10 million years, thus placing the Chrysochloridae
among the slower-evolving chromosomal lineages thus far recorded.
Electronic supplementary material Supplementary material to this paper is available in electronic form at and is accessible for authorized users. 相似文献
9.
Xiuguang Mao Wenhui Nie Jinhuan Wang Weiting Su Lei Ao Qing Feng Yingxiang Wang Marianne Volleth Fengtang Yang 《Chromosome research》2007,15(7):835-848
Rhinolophus (Rhinolophidae) is the second most speciose genus in Chiroptera and has extensively diversified diploid chromosome numbers
(from 2n = 28 to 62). In spite of many attempts to explore the karyotypic evolution of this genus, most studies have been
based on conventional Giemsa staining rather than G-banding. Here we have made a whole set of chromosome-specific painting
probes from flow-sorted chromosomes of Aselliscus stoliczkanus (Hipposideridae). These probes have been utilized to establish the first genome-wide homology maps among six Rhinolophus species with four different diploid chromosome numbers (2n = 36, 44, 58, and 62) and three species from other families: Rousettus leschenaulti (2n = 36, Pteropodidae), Hipposideros larvatus (2n = 32, Hipposideridae), and Myotis altarium (2n = 44, Vespertilionidae) by fluorescence in situ hybridization. To facilitate integration with published maps, human paints were also hybridized to A. stoliczkanus chromosomes. Our painting results substantiate the wide occurrence of whole-chromosome arm conservation in Rhinolophus bats and suggest that Robertsonian translocations of different combinations account for their karyotype differences. Parsimony
analysis using chromosomal characters has provided some new insights into the Rhinolophus ancestral karyotype and phylogenetic relationships among these Rhinolophus species so far studied. In addition to Robertsonian translocations, our results suggest that whole-arm (reciprocal) translocations
involving multiple non-homologous chromosomes as well could have been involved in the karyotypic evolution within Rhinolophus, in particular those bats with low and medium diploid numbers. 相似文献
10.
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
11.
Nobuko Ohmido Akiko Ishimaru Seiji Kato Shusei Sato Satoshi Tabata Kiichi Fukui 《Chromosome research》2010,18(2):287-299
To construct a high-resolution pachytene chromosome map, we used the chromosome image analyzing system version 3 and fluorescence
in situ hybridization. Two ribosomal RNA genes (45S rDNA and 5S rDNA), two major tandem repeat DNAs (LjTR1 and LjTR2), two major
retroelements (LjRE1 and LjRE2), and 27 transformation-competent artificial chromosome clones were physically localized on
Lotus japonicus (Miyakojima MG-20, 2n = 12) chromosomes. The distributions of heterochromatin and euchromatin along six chromosomes were
compared based on the linkage map. Distortion between the recombination frequencies and physical chromosomal distance was
recognized where the centromeric heterochromatic regions and constitutive heterochromatin are composed of the highest copy
tandem repeat LjTR1 on the interstitial specific regions. Our study shows that the heterochromatin are composed of the specific
repeated sequences, and the discrepancy between the recombination frequency and cytological information detected in L. japonicus chromosomes is due to the heterochromatin. 相似文献
12.
There are only a few reports on the chromosomal location of DNA sequences in bivalve species, none of them using meiotic chromosomes. Mitotic chromosomes of the clam Dosinia exoleta were analysed by means of Giemsa, silver and fluorochrome staining and fluorescent in situ hybridization (FISH) with 18S + 28S rDNA and telomeric probes. A technique for surface spreading of synaptonemal complexes (SCs) of Dosinia exoleta was developed for the first time in a bivalve species. Silver and DAPI/PI staining and SC-FISH were also applied to the study of the meiotic chromosomes of this clam. The diploid chromosome number in this species is 38 and the karyotype is composed of 11 pairs of metacentric and eight pairs of submetacentric chromosomes. 18S + 28S rDNA clusters map to the subtelomeric region of the short arm of one metacentric chromosome pair whereas telomeric signals appear at both ends of every chromosome. 相似文献
13.
Josefa Cabrero Ma. Dolores López-León María Teruel Juan Pedro M. Camacho 《Chromosome research》2009,17(3):397-404
We analyse chromosome location of H3 and H4 histone gene clusters by fluorescence in-situ hybridization (FISH) in 35 species
of Acrididae grasshoppers belonging to seven subfamilies. As in other organisms, H3 and H4 co-localized in the same chromosome
region in the 11 species where double FISH was performed with the H3 and H4 DNA probes. Chromosome location of H3-H4 histone
gene clusters showed high regularity in the species analysed, with all of them carrying a single H3-H4 cluster in an autosome
which, in most cases, was located interstitially in the proximal chromosome third. In 17 out of the 21 species with 2n♂ = 23
acrocentric chromosomes, the H3-H4-carrying autosome was about eighth in order of decreasing size. Two of the four exceptions
changed H3-H4 localization to proximal (Pezotettix giornae) or distal (Tropidopola graeca) in the eighth-sized autosome, but the remainder (the two Eyprepocnemis species) showed the H3-H4 cluster distally located in the second-sized autosome. All 14 species with 2n♂ = 17 chromosomes
(including three long metacentric autosome pairs, five acrocentric autosome pairs and an acrocentric X chromosome) carried
an interstitial H3-H4 cluster in the short arm of the smallest of the three long metacentric pairs. These results suggest
that chromosome location of H3-H4 histone gene clusters seem to be highly conservative in Acrididae grasshoppers. The change
in H3-H4 location from the acrocentric medium-sized autosome in the 2n♂ = 23 karyotype to the long metacentric autosome in
the 2n♂ = 17 karyotype is most parsimoniously explained by common ancestry, i.e. by the involvement of the H3-H4-carrying
acrocentric in the centric fusion that gave rise to the smallest of the three long metacentric autosomes of 2n♂ = 17 species. 相似文献
14.
15.
Reblánová M Spakulová M Orosová M Králová-Hromadová I Bazsalovicsová E Rajský D 《Parasitology research》2011,109(4):1021-1028
Chromosomal characteristics, i.e., number, size, morphology, and location of ribosomal DNA (rDNA) clusters were examined in
two medically important liver flukes, Fasciola hepatica and Fascioloides magna (Fasciolidae), using conventional Giemsa staining and fluorescent in situ hybridization (FISH) with ribosomal 18S rDNA probe.
A comparison of F. magna and F. hepatica karyotypes confirmed significant differences in all chromosomal features. Whilst the karyotype of F. hepatica comprised ten pairs of chromosomes (one metacentric and nine medium-sized subtelocentrics and submetacentrics; 2n = 20, n = 1 m + 5 sm + 4 st; TCL = 49.9 μm), the complement of F. magna was composed of 11 pairs of medium-sized subtelocentrics and submeta-metacentrics (2n = 22, n = 9 st + 1 sm + 1 sm-m; TCL = 35.2 μm). Noticeable differences were found mainly in length and morphology of first chromosome
pair. It was metacentric and 9.0 μm long in F. hepatica while subtelocentric and 4.7 μm long in F. magna. Although FISH with rDNA probe revealed a single cluster of ribosomal genes in both species, conspicuous interspecific differences
were displayed by chromosomal location of ribosomal loci (i.e., NORs). The signals were found on short arms of fifth homologous
pair in F. hepatica; however, they were detected in pericentromeric regions of the long arms of tenth pair in F. magna. The observed cytogenetic differences were interpreted in terms of karyotype evolution of fasciolid flukes; F. hepatica may be regarded phylogenetically younger than F. magna. The present paper provides a pilot study on molecular cytogenetics within a group of hermaphroditic digenetic flukes. 相似文献
16.
We investigated chromosome evolution in Nemesia using fluorescent in-situ hybridization (FISH) to identify the locations of 5S and 45S (18–26S) ribosomal genes. Although there was conservation between
Nemesia species in chromosome number, size and centromere position, there was large variation in both number and position of ribosomal
genes in different Nemesia species (21 different arrangements of 45S and 5S rRNA genes were observed in the 29 Nemesia taxa studied). Nemesia species contained between one and three pairs of 5S arrays and between two and four pairs of 45S arrays. These were either
sub-terminally or interstitially located and 45S and 5S arrays were often located on the same chromosome pair. Comparison
of the positions of rDNA arrays with meiotic chromosome behaviour in interspecific hybrids of Nemesia suggests that some of the changes in the positions of rDNA have not affected the surrounding chromosome regions, indicating
that rDNA has changed position by transposition. Chromosome evolution is frequently thought to occur via structural rearrangements
such as inversions and translocations. We suggest that, in Nemesia, transposition of rDNA genes may be equally if not more important in chromosome evolution. 相似文献
17.
Marta Gromicho Jean-Pierre Coutanceau Catherine Ozouf-Costaz Maria João Collares-Pereira 《Chromosome research》2006,14(3):297-306
The diploid–polyploid Squalius alburnoides complex resulted from interspecific hybridization. The chromosomal mapping of 28S and 5S ribosomal genes and of (TTAGGG)n telomeric repeats was performed on specimens from the complex and from the sympatric bisexual species S. pyrenaicus (the complex maternal ancestor) as part of an investigation of the evolutionary relationships between genomic constitutions
and the consequences of the ongoing polyploidization process in terms of chromosome reshaping. Contrasting results were obtained.
While results with 5S rDNA and telomeric probes gave an impression of genomic stability, the variability detected with 28S
rDNA probe suggested quite the opposite. The 5S rDNA probe mapped constantly to three chromosomes per haploid genome with
apparently conserved locations in morphologically similar chromosomes; conversely, prominent intra- and inter-individual variations
of 28S rDNA and of syntenic sites with 5S rDNA were detected with regard to number, size and location. Hypotheses for the
causes of such polymorphisms are discussed. The terminal position of most 28S rDNA sites and the absence of detectable interstitial
telomeric sequences suggest a mechanism that does not involve major chromosomal rearrangements. These fishes share similar
patterns for the studied cytogenetic markers which may be taken as evidence of an apparent stability that may be hiding extensive
and subtle genome variations that are possibly related to an ongoing evolutionary process of genome tetraploidization and
speciation. 相似文献
18.
19.
Natalia S. Zhdanova Julia M. Minina Tatjana V. Karamisheva Irena Draskovic Nikolai B. Rubtsov Jose-Arturo Londoño-Vallejo 《Chromosome research》2007,15(7):881-890
Two closely related shrew species, Sorex granarius and Sorex araneus, in which Robertsonian rearrangements have played a primary role in karyotype evolution, present very distinct telomere length
patterns. S. granarius displays hyperlong telomeres specifically associated with the short arms of acrocentrics, whereas telomere lengths in S. araneus are rather short and homogenous. Using a combined approach of chromosome and fibre FISH, modified Q-FISH, 3D-FISH, Ag-NOR
staining and TRF analysis, we carried out a comparative analysis of telomeric repeats and rDNA distribution on chromosome
ends of Sorex granarius. Our results show that rDNA sequences forming active nuclear organizing regions are interspersed with the long telomere tracts
of all short arms of acrocentrics. These observations suggest that the major rearrangements that gave rise to today’s karyotype
in S. granarius were accompanied by a profound reorganization of chromosome ends, which comprised extensive amplification of telomeric and
rDNA repeats on the short arms of acrocentrics and finally contributed to the stabilization of telomeres. This is the first
time that such telomeric structures have been observed in any mammalian species. 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