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1.
The multiple sex chromosome system, X1X2Y /X1X1X2X2, in the small Indian mongoose, Herpestes auropunctatus, results from a translocation of a part of Y chromosome to an autosome. It is not possible to distinguish the autosome which harbours the Y chromosome element in the somatic complement. By employing the surface-spreading technique to prophase I meiocytes we have identified the region to which the Y chromosome has been translocated as the short arm of chromosome 9 which is a subtelocentric chromosome. This Y chromosome component lacks heterochromatin and no sex vesicle is organised during meiotic prophase. This suggests to us that Y heterochromatin in mammals may be required for the production of a sex vesicle.We take great pleasure in dedicating this paper to our revered teacher Prof. S.P. Ray-Chaudhuri, who initiated us to the field of Cytogenetics, on the occasion of his 75th birth day 相似文献
2.
Sex chromosome evolution in fish: the formation of the neo-Y chromosome in Eigenmannia (Gymnotiformes) 总被引:4,自引:0,他引:4
Chromosomes of a species of Eigenmannia presenting a X1X1X2X2:X1X2Y sex chromosome system, resulting from a Y-autosome Robertsonian translocation, were analyzed using the C-banding technique,
chromomycin A3 (CMA3) and mithramycin (MM) staining and in situ digestion by the restriction endonuclease AluI. A comparison of the metacentric Y chromosome of males with the corresponding acrocentrics in females indicated that a C-band-positive,
CMA3/MM-fluorescent and AluI digestion-resistant region had been lost during the process of translocation, resulting in a diminution
of heterochromatin in the males. It is hypothesized that the presence of a smaller amount of G+C-rich heterochromatin in the
sex chromosomes of the heteromorphic sex when compared with the homomorphic sex may be associated with the sex determination
mechanism in this species and may be a more widely occurring phenomenon in fish with differentiated sex chromosomes than was
initially thought.
Received: 1 April 1999; in revised form: 16 October 1999 / Accepted: 4 December 1999 相似文献
3.
Cellular suspensions of germinal tissues of Cylindera trisignata provided the definition of its karyotype: 2n=23 and 2n=26 for the males and females respectively. This Palearctic species has a sex chromosome system of the X1X2X3X4Y / X1X1X2X2X3X3X4X4 type, only found until now in Cicindela maroccana pseudomaroccana. The heterosomes are not well-differentiated from the general morphological standpoint. To explain the origin of the 4X condition, a mechanism of dissociation of the X chromosomes rather than an incorporation of autosomal segments is proposed. However, based on the occurrence of distinct ploidy levels, both in male and female cells, with a relatively high incidence for the tetraploid condition with regular autosomal bivalents, the hypothesis of a possible evolutionary role of polyploidy is suggested. 相似文献
4.
Cytotaxonomy of the triatominae (Reduviidae: Hemiptera) 总被引:1,自引:0,他引:1
Norihiro Ueshima 《Chromosoma》1966,18(1):97-122
The chromosome number and meiotic cycle of 20 species of Triatominae have been investigated. In the male, there are five types of chromosome complement: 20+XY, 20+X1X2Y, 20+X1X2X3Y, 18+XY and 22+XY.The cytological data suggest that the type number for the subfamily is 22 (20+XY). In the hybrids: Triatoma barberi () and T. protracta (), anomalous behavior of certain chromosomes has been observed. Phylogenetic relationships based on chromosome evidence in the subfamily have been discussed. It is suggested that fragmentation is the major factor for chromosome evolution in the group. 相似文献
5.
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7.
James H. Oliver Jr. 《Chromosoma》1965,17(4):323-327
Summary Prior to this paper there have been no reports of a multiple sex chromosome mechanism operative in any tick. The present paper deals with two species of Ixodidae, Amblyomma moreliae and Amblyomma limbatum that exhibit an X1X1X2X2:X1X2Y type of sex chromosome mechanism. Cells from males of both species show nine bivalents plus one sex trivalent. Eleven bivalents were observed in one female A. moreliae. The sex trivalent probably evolved through reciprocal translocation from a system that included ten autosomal bivalents and one sex univalent (the system found in most ixodid species). As a result of the translocation, there are now two X chromosomes (X1 and X2) segregating from an unaltered autosome, the neo-Y. A large X chromosome is characteristic of many ticks; in this instance the reciprocal translocation did not change appreciably its relative size.The opinions and assertions contained herein are the private ones of the author and are not to be construed as official or reflecting the views of the Navy Department or the Naval service at large.This study was begun during the tenure of a North Alantic Treaty Organization (National Science Foundation) Postdoctoral Fellowship. 相似文献
8.
Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera,Belostoma)
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Mónica G. Chirino Martina Dalíková František R. Marec María J. Bressa 《Ecology and evolution》2017,7(14):5227-5235
Tandem arrays of TTAGG repeats show a highly conserved location at the telomeres across the phylogenetic tree of arthropods. In giant water bugs Belostoma, the chromosome number changed during speciation by fragmentation of the single ancestral X chromosome, resulting in a multiple sex chromosome system. Several autosome–autosome fusions and a fusion between the sex chromosome pair and an autosome pair resulted in the reduced number in several species. We mapped the distribution of telomeric sequences and interstitial telomeric sequences (ITSs) in Belostoma candidulum (2n = 12 + XY/XX; male/female), B. dentatum (2n = 26 + X1X2Y/X1X1X2X2), B. elegans (2n = 26 + X1X2Y/X1X1X2X2), B. elongatum (2n = 26 + X1X2Y/X1X1X2X2), B. micantulum (2n = 14 + XY/XX), and B. oxyurum (2n = 6 + XY/XX) by FISH with the (TTAGG)n probes. Hybridization signals confirmed the presence of TTAGG repeats in the telomeres of all species examined. The three species with reduced chromosome numbers showed additional hybridization signals in interstitial positions, indicating the occurrence of ITS. From the comparison of all species here analyzed, we observed inverse relationships between chromosome number and chromosome size, and between presence/absence of ITS and chromosome number. The ITS distribution between these closely related species supports the hypothesis that several telomere–telomere fusions of the chromosomes from an ancestral diploid chromosome number 2n = 26 + XY/XX played a major role in the karyotype evolution of Belostoma. Consequently, our study provide valuable features that can be used to understand the karyotype evolution, may contribute to a better understanding of taxonomic relationships, and also elucidate the high plasticity of nuclear genomes at the chromosomal level during the speciation processes. 相似文献
9.
The karyotype and other chromosomal markers as revealed by C-banding and Ag-staining were studied in Lutjanus quinquelineatus and L. kasmira (Lutjanidae, Perciformes). While in latter species, the karyotype was invariably composed of 48 acrocentric chromosomes in
both sexes, in L. quinquelineatus the female karyotype had exclusively 48 acrocentric chromosomes (2n = 48) but that of the male consisted of one large metacentric and 46 acrocentric chromosomes (2n = 47). The chromosomes in the first meiotic division in males showed 22 bivalents and one trivalent, which was formed by
an end-to-end association and a chiasmatic association. Multiple sex chromosome system of X1X1X2X2/X1X2Y type resulting from single Robertsonian fusion between the original Y chromosome and an autosome was hypothesized to produce
neo-Y sex chromosome. The multiple sex chromosome system of L. quinquelineatus appears to be at the early stage of the differentiation. The positive C-banded heterochromatin was situated exclusively in
centromeric regions of all chromosomes in both species. Similarly, nucleolus organizer region sites were identified in the
pericentromeric region of one middle-sized pair of chromosomes in both species. The cellular DNA contents were the same (3.3 pg)
between the sexes and among this species and related species. 相似文献
10.
Leandro Marajó Patrik Ferreira Viana Alex Matheus Viana Ferreira Lúcia Helena Rapp Py-Daniel Marcelo de Bello Cioffi Alexandr Sember Eliana Feldberg 《Journal of fish biology》2023,102(2):443-454
Rineloricaria is the most diverse genus within the freshwater fish subfamily Loricariinae, and it is widely distributed in the Neotropical region. Despite limited cytogenetic data, records from southern and south-eastern Brazil suggest a high rate of chromosomal rearrangements in this genus, mirrored in remarkable inter- and intraspecific karyotype variability. In the present work, we investigated the karyotype features of Rineloricaria teffeana, an endemic representative from northern Brazil, using both conventional and molecular cytogenetic techniques. We revealed different diploid chromosome numbers (2n) between sexes (33♂/34♀), which suggests the presence of an ♀X1X1X2X2/♂X1X2Y multiple sex chromosome system. The male-limited Y chromosome was the largest and the only biarmed element in the karyotype, implying Y-autosome fusion as the most probable mechanism behind its origination. C-banding revealed low amounts of constitutive heterochromatin, mostly confined to the (peri)centromeric regions of most chromosomes (including the X2 and the Y) but also occupying the distal regions of a few chromosomal pairs. The chromosomal localization of the 18S ribosomal DNA (rDNA) clusters revealed a single site on chromosome pair 4, which was adjacent to the 5S rDNA cluster. Additional 5S rDNA loci were present on the autosome pair 8, X1 chromosome, and in the presumed fusion point on the Y chromosome. The probe for telomeric repeat motif (TTAGGG)n revealed signals of variable intensities at the ends of all chromosomes except for the Y chromosome, where no detectable signals were evidenced. Male-to-female comparative genomic hybridization revealed no sex-specific or sex-biased repetitive DNA accumulations, suggesting a presumably low level of neo-Y chromosome differentiation. We provide evidence that rDNA sites might have played a role in the formation of this putative multiple sex chromosome system and that chromosome fusions originate through different mechanisms among different Rineloricaria species. 相似文献
11.
L. Vosselman 《Chromosoma》1978,67(3):201-218
X and Y chromosomes of Hylemya antiqua occur in two forms each. XL and XS, and Y1 and Y2. The larger XL has an intercalary proximal segment which is absent in the more common smaller XS. The acrocentric Y chromosome (Y1), does not differ morphologically from XS. A smaller metacentric Y2 is apparently not homologous with Y1. Two types of males, XY1 and XXY2, coexist in at least one Dutch population. XY2 has been observed in one individual only. In larval ganglion cells an association has been observed between chromosome Y2 and a probably non-homologous, intercalary segment of autosome 4. A numerical somatic variation of Y2 can lead to gynandromorphs and sex ratios significantly different from 1∶1. XX cells can differentiate into functional spermatozoa
in XX/XXY2 mosaic testes. This indicates the presence of a diffusable male determining substance, which can reverse the “genotypic”
sex of a cell. The occurrence of some spermatozoa-containing “cysts” in ovaries of two gynanders suggests a more or less autonomous
(independent of the gonadal environment) differentiation of XXY2 germ cells. XXXY2 males and XXX females do not show a serious reduction in fertility. Even XXXXY2 males do not exhibit any sign of intersexuality and spermatogenesis seems unaffected. All 62 scored M II cells of X-tetrasomic
males contained 2 Xs. 相似文献
12.
R. Rosa M. Caetano‐Filho O. A. Shibatta L. Giuliano‐Caetano 《Journal of fish biology》2009,75(10):2682-2694
Cytogenetic and morphometric analyses were carried out in Hoplias aff. malabaricus specimens from six distinct populations from the lower Paranapanema River basin, located between the states of Paraná and São Paulo, Brazil. Measurements were also taken from a specimen collected in Surinam. In a population from a fish farm station at Universidade do Norte do Parana (EPUNOPAR), two sympatric cytotypes (2n = 40 and 2n = 42 chromosomes) are found. A population from a fish farm station at Universidade Estadual de Londrina (EPUEL) shows 2n = 42 meta–submetacentric chromosomes for males and females with a simple sex chromosome system of XX/XY type. Populations from the Vermelho and Rancho Alegre Rivers, Três Bocas Stream and Paranapanema River have 2n = 39 chromosomes in males and 2n = 40 chromosomes in females, showing a multiple sex chromosome system of X1X1X2X2/X1X2Y type. Twenty morphological variables were studied. These measurements were used for an analysis of the canonical variables and standard analysis of proportional measurements. The most variable measurements among the specimens are the maxilla length (MXL) and the pre‐dorsal distance (PDD). Analysis of canonical variables indicates three distinct groups in the first canonical axis formed by: (1) Três Bocas Stream, (2) Rancho Alegre + Vermelho River + EPUNOPAR and (3) EPUEL + Paranapanema River. This axis retained 79·4% of information from the original matrix. Analysis of morphometrics reveals differences among populations from the Paranapanema River basin and between these and the specimen from Surinam. The morphometric and cytogenetic differences among the studied populations suggest a species complex. 相似文献
13.
Geize Aparecida Deon Larissa Glugoski Terumi Hatanaka Francisco de Menezes Cavalcante Sassi Viviane Nogaroto Luiz Antonio Carlos Bertollo Thomas Liehr Ahmed Al-Rikabi Orlando Moreira Filho Marcelo de Bello Cioffi Marcelo Ricardo Vicari 《Genetics and molecular biology》2022,45(2)
The Neotropical armored catfish genus Harttia presents a wide variation of chromosomal rearrangements among its representatives. Studies indicate that translocation and Robertsonian rearrangements have triggered the karyotype evolution in the genus, including differentiation of sex chromosome systems. However, few studies used powerful tools, such as comparative whole chromosome painting, to clarify this highly diversified scenario. Here, we isolated probes from the X1 (a 5S rDNA carrier) and the X2 (a 45S rDNA carrier) chromosomes of Harttia punctata, which displays an X1X1X2X2/X1X2Y multiple sex chromosome system. Those probes were applied in other Harttia species to evidence homeologous chromosome blocks. The resulting data reinforce that translocation events played a role in the origin of the X1X2Y sex chromosome system in H. punctata. The repositioning of homologous chromosomal blocks carrying rDNA sites among ten Harttia species has also been demonstrated. Anchored to phylogenetic data it was possible to evidence some events of the karyotype diversification of the studied species and to prove an independent origin for the two types of multiple sex chromosomes, XX/XY1Y2 and X1X1X2X2/X1X2Y, that occur in Harttia species. The results point to evolutionary breakpoint regions in the genomes within or adjacent to rDNA sites that were widely reused in Harttia chromosome remodeling. 相似文献
14.
Wayne Paul Maddison 《Chromosoma》1982,85(1):23-37
Observations of male meiosis and female chromosome number indicate that eight species of Pellenes have the X1X2O male, X1X1X2X2 female sex chromosome system typical of salticids, four species have an X1X2X3Y male, X1X1X2X3X3X3 female system, and one species has both X1X2O and X1X2X3Y males. This is the first report of a Y chromosome in spiders. It is hypothesized that the X1X2X2Y system was derived from an X1X2O system by a tandem X-autosome fusion which yielded the X2 and a centric autosome-autosome fusion which yielded the Y. Data on heteropycnosis, chiasmata, segregation, chromosome number and arm length support this hypothesis. The distribution of the X1X2X3Y system within the genus is phylogenetically confusing and suggests that the two sex chromosome systems have been maintained together as a polymorphism in some lineages for long periods of time or that there have been repeated derivations of the X1X2X3Y or X1X2O systems. 相似文献
15.
Anoles are a clade of iguanian lizards that underwent an extensive radiation between 125 and 65 million years ago. Their karyotypes show wide variation in diploid number spanning from 26 (Anolis evermanni) to 44 (A. insolitus). This chromosomal variation involves their sex chromosomes, ranging from simple systems (XX/XY), with heterochromosomes represented by either micro- or macrochromosomes, to multiple systems (X1X1X2X2/X1X2Y). Here, for the first time, the homology relationships of sex chromosomes have been investigated in nine anole lizards at the whole chromosome level. Cross-species chromosome painting using sex chromosome paints from A. carolinensis, Ctenonotus pogus and Norops sagrei and gene mapping of X-linked genes demonstrated that the anole ancestral sex chromosome system constituted by microchromosomes is retained in all the species with the ancestral karyotype (2n?=?36, 12 macro- and 24 microchromosomes). On the contrary, species with a derived karyotype, namely those belonging to genera Ctenonotus and Norops, show a series of rearrangements (fusions/fissions) involving autosomes/microchromosomes that led to the formation of their current sex chromosome systems. These results demonstrate that different autosomes were involved in translocations with sex chromosomes in closely related lineages of anole lizards and that several sequential microautosome/sex chromosome fusions lead to a remarkable increase in size of Norops sagrei sex chromosomes. 相似文献
16.
Wayne P. Maddison Geneviève Leduc‐Robert 《Evolution; international journal of organic evolution》2013,67(8):2258-2272
Entelegyne spiders rarely show fusions yielding neo‐Y chromosomes, which M. J. D. White attributed to a constraint in spiders, namely their proximal chiasma localization acting to upset meiotic segregation in males with fusions. Of the 75 taxa of Habronattus and outgroups studied, 47 have X1X20 sex chromosomes in males, 10 have X1X2Y, 15 have X1X2X3Y, 2 have X0, and one has both X1X20 and X1X2X3Y. Chromosome numbers and behavior suggest neo‐Ys formed by an autosome‐X fusion to make X1X2Y, with a second fusion to an autosome to make X1X2X3Y. Phylogeny shows at least 8–15 gains (or possibly some losses) of neo‐Y (i.e., X‐autosome fusions), a remarkable number for such a small clade. In contrast to the many X‐autosome fusions, at most one autosome–autosome fusion is indicated. Origins of neo‐Y are correlated significantly with distal localization of chiasmata, supporting White's hypothesis that evolution of neo‐Y systems is facilitated by looser pairing (distal chiasmata) at meiosis. However, an alternative (or contributing) explanation for the correlation is that X‐autosome fusions were selected to permit isolation of male‐favored alleles to the neo‐Y chromosome, aided by distal chiasmata limiting recombination. This intralocus sexual conflict hypothesis could explain both the many X‐autosome fusions, and the stunning complexity of male Habronattus courtship displays. 相似文献
17.
Norihiro Ueshima 《Chromosoma》1967,20(3):311-331
The chromosome complement in the human bed bug, Cimex lectularius
Linn., is 26+X1X2Y in the male and 26+X1X1X2X2 in the female. However, a population from Cairo, Egypt has 4 supernumerary X chromosomes. In the hybrid between the Berkeley population (with no supernumeraries) and the Cairo population (with 4 supernumeraries), the behavior of supernumeraries was observed during embryogenesis and oogenesis as well as spermatogenesis.In embryogenesis the transmission of supernumeraries was quite regular. However, one chromosome may sometimes be eliminated early in the germ line. This abnormality could induce the variations in chromosome number encountered in later stages. In the first meiotic division, some of the supernumeraries were nondisjunctional. Moreover, in the second division, some supernumeraries were eliminated. These results show that there is a tendency towards a decrease in the number of supernumeraries in the hybrids.Although the supernumeraries behave like X chromosomes, they seem not to be important for sex determination and appear to be largely or entirely inert genetically. Supernumeraries in the bed bug originate from small fragments caused by structural rearrangement. They are increased by an accumulation mechanism. Supernumeraries in the bed bug appear to be of relatively recent origin. The phylogenetic sequence in their development was probably from none to a stabilized number of four in the Old World. Then the supernumeraries were lost in two specialized lines, Cimex columbarius
Jenyns on domestic birds in Europe and Cimex lectularius
Linn. on man in the Western Hemisphere.This study was carried out under U.S. Public Health Service Grant (GM-13197). 相似文献
18.
Daniel Rodrigues Blanco Marcelo Ricardo Vicari Roberto Laridondo Lui Roberto Ferreira Artoni Mara Cristina de Almeida Josiane Baccarin Traldi Vladimir Pavan Margarido Orlando Moreira-Filho 《Genetica》2014,142(2):119-126
Harttia is a genus in the subfamily Loricariinae that accommodates fishes popularly known as armored catfishes. They show extensive karyotypic diversity regarding interspecific numerical/structural variation of the karyotypes, with the presence of the XX/XY1Y2 multiple sex chromosome system, as found in H. carvalhoi. In this context, this study aimed to characterize Harttia punctata chromosomally, for the first time, and to infer the rearrangements that originated the X1X1X2X2/X1X2Y multiple sex chromosome system present in this species. The data obtained in this study, with classical (Giemsa, C-banding and AgNORs) and molecular methodologies (fluorescence in situ hybridization) and chromosome microdissection, indicated that a translocation between distinct acrocentric chromosomes bearing rRNA genes, accompanied by deletions in both chromosomes, might have originated the neo-Y chromosome in this species. The data also suggest that the multiple sex chromosome systems present in H. carvalhoi and H. punctata had an independent origin, evidencing the recurrence of chromosome alterations in species from this genus. 相似文献
19.
Adauto Lima Cardoso Julio Cesar Pieczarka Cleusa Yoshiko Nagamachi 《Genetics and molecular biology》2015,38(2):213-219
Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes. 相似文献
20.
de Bello Cioffi M Sánchez A Marchal JA Kosyakova N Liehr T Trifonov V Bertollo LA 《Genetica》2011,139(8):1065-1072
The wolf fish Hoplias malabaricus includes well differentiated sex systems (XY and X1X2Y in karyomorphs B and D, respectively), a nascent XY pair (karyomorph C) and not recognized sex chromosomes (karyomorph A).
We performed the evolutionary analysis of these sex chromosomes, using two X chromosome-specific probes derived by microdissection
from the XY and X1X2Y sex systems. A putative-sex pair in karyomorph A was identified, from which the differentiated XY system was evolved, as
well as the clearly evolutionary relationship between the nascent XY system and the origin of the multiple X1X2Y chromosomes. The lack of recognizable signals on the sex chromosomes after the reciprocal cross-FISH experiments highlighted
that they evolved independently from non-homologous autosomal pairs. It is noteworthy that these distinct pathways occur inside
the same nominal species, thus exposing the high plasticity of sex chromosome evolution in lower vertebrates. Possible mechanisms
underlying this sex determination liability are also discussed. 相似文献