scholarly journals In SituGene Mapping of Two Genes Supports Independent Evolution of Sex Chromosomes in Cold-Adapted Antarctic Fish

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Laura Ghigliotti ◽  
C.-H. Christina Cheng ◽  
Céline Bonillo ◽  
Jean-Pierre Coutanceau ◽  
Eva Pisano
Keyword(s):  
Sex Chromosome ◽  
Antarctic Fish ◽  
5S Rdna ◽  
Cold Adapted ◽  
Antifreeze Glycoprotein ◽  
Y Chromosomes ◽  
Pagothenia Borchgrevinki ◽  
History Of ◽  
Sex Chromosome System

Two genes, that is, 5S ribosomal sequences and antifreeze glycoprotein (AFGP) genes, were mapped onto chromosomes of eight Antarctic notothenioid fish possessing a X1X1X2X2/X1X2Y sex chromosome system, namely,Chionodraco hamatusandPagetopsis macropterus(family Channichthyidae),Trematomus hansoni,T. newnesi,T. nicolai,T. lepidorhinus, andPagothenia borchgrevinki(family Nototheniidae), andArtedidraco skottsbergi(family Artedidraconidae). Through fluorescencein situhybridization (FISH), we uncovered distinct differences in the gene content of the Y chromosomes in the eight species, withC. hamatusandP. macropterusstanding out among others in bearing 5S rDNA and AFGP sequences on their Y chromosomes, respectively. Both genes were absent from the Y chromosomes of any analyzed species. The distinct patterns of Y and non-Y chromosome association of the 5S rDNA and AFGP genes in species representing different Antarctic fish families support an independent origin of the sex heterochromosomes in notothenioids with interesting implications for the evolutionary/adaptational history of these fishes living in a cold-stable environment.

Analysis of SINE and LINE repeat content of Y chromosomes in the platypus, Ornithorhynchus anatinus

2009 ◽  
Vol 21 (8) ◽  
pp. 964 ◽  
Author(s):  
R. Daniel Kortschak ◽  
Enkhjargal Tsend-Ayush ◽  
Frank Grützner
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Activity Patterns ◽  
Specific Sequence ◽  
X Chromosomes ◽  
Repeat Content ◽  
Y Chromosomes ◽  
Ornithorhynchus Anatinus ◽  
History Of ◽  
Sex Chromosome System

Monotremes feature an extraordinary sex-chromosome system that consists of five X and five Y chromosomes in males. These sex chromosomes share homology with bird sex chromosomes but no homology with the therian X. The genome of a female platypus was recently completed, providing unique insights into sequence and gene content of autosomes and X chromosomes, but no Y-specific sequence has so far been analysed. Here we report the isolation, sequencing and analysis of ~700 kb of sequence of the non-recombining regions of Y2, Y3 and Y5, which revealed differences in base composition and repeat content between autosomes and sex chromosomes, and within the sex chromosomes themselves. This provides the first insights into repeat content of Y chromosomes in platypus, which overall show similar patterns of repeat composition to Y chromosomes in other species. Interestingly, we also observed differences between the various Y chromosomes, and in combination with timing and activity patterns we provide an approach that can be used to examine the evolutionary history of the platypus sex-chromosome chain.

scholarly journals A new Roncus species (Pseudoscorpiones: Neobisiidae) from Montseny Natural Park (Catalonia, Spain), with remarks on karyology

Zootaxa ◽  
2008 ◽  
Vol 1693 (1) ◽  
pp. 27 ◽  
Author(s):  
JUAN A. ZARAGOZA ◽  
FRANTI“EK ŠÿÁHLAVSKÝ
Keyword(s):  
New Species ◽  
Diploid Number ◽  
Sex Chromosome ◽  
Natural Park ◽  
Y Chromosomes ◽  
Sex Chromosome System ◽  
Acrocentric Chromosomes

Roncus montsenyensis sp. nov. is described from Montseny Natural Park (Catalonia, Spain). The new species is geographically and morphologically close to Roncus cadinensis Zaragoza, 2007, but can be separated from it by palpal morphometrics, the chelal microsetae pattern and karyology. The diploid number was found to be 2n=16 in R. montsenyensis, with only biarmed chromosomes. The diploid number was found to be 2n=38 in R. cadinensis, with a predominance of acrocentric chromosomes. Both species possess the XY sex chromosome system and the X and Y chromosomes are only weakly differentiated.

scholarly journals Seed sexing revealed female bias in two Rumex species

2011 ◽  
Vol 80 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Dagmara Kwolek ◽  
Andrzej J. Joachimiak
Keyword(s):  
Sex Ratio ◽  
Sex Chromosomes ◽  
Dna Markers ◽  
Sex Chromosome ◽  
Sex Ratios ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Y Chromosomes ◽  
Sex Chromosome System ◽  
Female Bias

Sex-ratio bias in seeds of dioecious <em>Rumex</em> species with sex chromosomes is an interesting and still unsettled issue. To resolve gender among seeds of <em>R. acetosa</em> and <em>R. thyrsiflorus</em> (two species with an XX/XY1Y2 sex chromosome system), this work applied a PCR-based method involving DNA markers located on Y chromosomes. Both species showed female-biased primary sex ratios, with female bias greater in <em>R. acetosa</em> than in <em>R. thyrsiflorus</em>. The observed predominance of female seeds is consistent with the view that the female biased sex ratios in <em>Rumex </em>are conditioned not only postzygotically but also prezygotically.

Nervous control of the spleen in the red-blooded Antarctic fish, Pagothenia borchgrevinki

1996 ◽  
Vol 270 (3) ◽  
pp. R599-R604 ◽  
Author(s):  
S. Nilsson ◽  
M. E. Forster ◽  
W. Davison ◽  
M. Axelsson
Keyword(s):  
Antarctic Fish ◽  
Cholinergic Innervation ◽  
Maximal Contraction ◽  
Nervous Control ◽  
Major Function ◽  
Pagothenia Borchgrevinki ◽  
The Antarctic ◽  
Stimulation Of

The mechanisms of splenic control in the Antarctic fish, Pagothenia borchgrevinki, were investigated using isolated spleen and mesenteric artery strips in vitro and perfused spleen preparations in situ. Splenosomatic index (SSI) [100 x (spleen wt/body wt)] and hematocrit were determined in animals treated with atropine and phentolamine. Atropine injection increased the SSI from 0.60 +/- 0.06 to 0.89 +/- 0.04, whereas phentolamine decreased SSI to 0.45 +/- 0.03. In atropine-injected fish, hematocrit was 18.6 +/- 1.4 before and 6.6 +/- 0.8% 3 h after injection. Electrical stimulation of the splenic nerves produced biphasic flow responses. In 11 of 12 tested preparations, atropine (3 x 10(-7) to 10(-6) M) abolished the response, suggesting a major cholinergic component in the splenic innervation. Isolated spleen strip preparations contracted in response to carbachol, a response that was antagonized by atropine. The response to acetylcholine was markedly enhanced by the specific cholinesterase inhibitor BW-284c51. Catecholamine effects were somewhat irregular, and maximal contraction force with epinephrine and norepinephrine was 41 and 56%, respectively, of the carbachol response. The results suggest a mainly, if not solely, cholinergic autonomic control of the borch spleen, and a major function of the cholinergic innervation in the control of hematocrit in this species.

A cytological study of species in Cnephia s. str. (Diptera: Simuliidae)

1982 ◽  
Vol 60 (11) ◽  
pp. 2866-2878 ◽  
Author(s):  
William S. Procunier
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Cytological Study ◽  
Chromosome Complement ◽  
Nucleolar Organizer ◽  
Sympatric Speciation ◽  
Basic Chromosome ◽  
Y Chromosomes ◽  
Norwegian Population ◽  
Sex Chromosome System

Cytological descriptions and phylogenetic relationships are presented for the genus Cnephia s. str. All members are male achiasmate. Cnephia lapponica is unique in that its basic chromosome complement is reduced from n = 3 to n = 2 metacentrics as a result of a fusion of chromosomes II and III. Sex chromosome differentiation varies from nonobservable in C. ornithophilia and C. eremites through C. pecuarum in which the standard and IS-5 sequences are distributed differentially over X and Y chromosomes, to the polytypic system of C. lapponica in which the X chromosome is fixed for expression of the nucleolar organizer (NO) and the Y chromosome for nonexpression. Further, in a Norwegian population of C. lapponica, males are additionally interchange heterozygotes. Thus, a multiple sex chromosome system exists in which all the chromosomes are sex chromosomes. Closest members occur sympatrically and differ by sex chromosomes and at least one fixed inversion; more distant taxa differ by a number of fixed inversions as well as sex chromosomes. The identical bands 17B and 24C, which appear in a thin or enhanced form, are polymorphic, sex-linked, fixed, or lost in different members of the group. This study supports a model for sympatric speciation.

scholarly journals Chromosomal Mapping of Repetitive DNAs in Characidium (Teleostei, Characiformes): Genomic Organization and Diversification of ZW Sex Chromosomes

2015 ◽  
Vol 146 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Priscilla C. Scacchetti ◽  
Ricardo Utsunomia ◽  
José C. Pansonato-Alves ◽  
Marcelo R. Vicari ◽  
Roberto F. Artoni ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Dna Sequences ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
5S Rdna ◽  
Chromosome Mapping ◽  
Chromosomal Mapping ◽  
Specific Probe ◽  
W Chromosome ◽  
Sex Chromosome System

The speciose neotropical genus Characidium has proven to be a good model for cytogenetic exploration. Representatives of this genus often have a conserved diploid chromosome number; some species exhibit a highly differentiated ZZ/ZW sex chromosome system, while others do not show any sex-related chromosome heteromorphism. In this study, chromosome painting using a W-specific probe and comparative chromosome mapping of repetitive sequences, including ribosomal clusters and 4 microsatellite motifs - (CA)15, (GA)15, (CG)15, and (TTA)10 -, were performed in 6 Characidium species, 5 of which possessed a heteromorphic ZW sex chromosome system. The W-specific probe showed hybridization signals on the W chromosome of all analyzed species, indicating homology among the W chromosomes. Remarkably, a single major rDNA-bearing chromosome pair was found in all species. The 18S rDNA localized to the sex chromosomes in C. lanei, C. timbuiense and C. pterostictum, while the major rDNA localized to one autosome pair in C. vidali and C. gomesi. In contrast, the number of 5S rDNA-bearing chromosomes varied. Notably, minor ribosomal clusters were identified in the W chromosome of C. vidali. Microsatellites were widely distributed across almost all chromosomes of the karyotypes, with a greater accumulation in the subtelomeric regions. However, clear differences in the abundance of each motif were detected in each species. In addition, the Z and W chromosomes showed the differential accumulation of distinct motifs. Our results revealed variability in the distribution of repetitive DNA sequences and their possible association with sex chromosome diversification in Characidium species.

Characterisation of ATRX, DMRT1, DMRT7 and WT1 in the platypus (Ornithorhynchus anatinus)

2009 ◽  
Vol 21 (8) ◽  
pp. 985 ◽  
Author(s):  
Enkhjargal Tsend-Ayush ◽  
Shu Ly Lim ◽  
Andrew J. Pask ◽  
Diana Demiyah Mohd Hamdan ◽  
Marilyn B. Renfree ◽  
...  
Keyword(s):  
Sex Determination ◽  
Expression Pattern ◽  
Sexual Development ◽  
Sex Chromosome ◽  
Z Chromosome ◽  
Testis Development ◽  
Y Chromosomes ◽  
Evolutionarily Conserved ◽  
Sex Chromosome System ◽  
Conserved Gene

One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location.

Diversity of Sex Chromosome Systems in Ancistrini (Loricariidae, Hypostominae): ZZ/ZW in Ancistrus taunayi Miranda Ribeiro, 1918

2015 ◽  
Vol 146 (4) ◽  
pp. 306-310 ◽  
Author(s):  
Jocicléia Thums Konerat ◽  
Vanessa Bueno ◽  
Vladimir P. Margarido ◽  
Ana L.B. Portela-Castro ◽  
Isabel C. Martins-Santos
Keyword(s):  
18S Rdna ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Acrocentric Chromosome ◽  
5S Rdna ◽  
Paracentric Inversion ◽  
Origin And Evolution ◽  
Agnor Staining ◽  
Rdna Fish ◽  
Sex Chromosome System

The karyotype of the Ancistrini catfish Ancistrus taunayi was analyzed by conventional (Giemsa staining, AgNOR staining and C-banding) and molecular cytogenetic (5S and 18S rDNA-FISH) methods. The diploid chromosome number was 2n = 50 (22 metacentrics + 10 submetacentrics + 10 subtelocentrics + 8 acrocentrics) for both sexes. A single NOR-bearing acrocentric chromosome pair (No. 24) was detected after Ag-staining and 18S rDNA-FISH, while 5S rDNA was found only in the subtelocentric pair No. 21. Conspicuous GC-rich heterochromatin blocks corresponded to the NOR sites and were also observed in the distal regions of the acrocentric chromosome pairs Nos. 22 and 25. Chromosome pair No. 22 differed between males and females; in males, only a small interstitial block of GC-rich heterochromatin was present in both chromosomes, whereas in females, 2 blocks of GC-rich heterochromatin flanked a euchromatic region in one of the homologues, suggesting the occurrence of a ZZ/ZW sex chromosome system. Two mechanisms for the origin and evolution of this simple ZZ/ZW sex chromosome system in A. taunayi are proposed: (1) a paracentric inversion followed by amplification of the proximal heterochromatin and (2) amplification of the interstitial heterochromatin followed by a paracentric inversion. Although ZZ/ZW systems have already been described for other Ancistrus species, our results do not show the same pattern, suggesting an independent origin.

Parental origin and genome evolution of several Eurasian hexaploid species of Chenopodium (Chenopodiaceae)

Phytotaxa ◽  
2019 ◽  
Vol 392 (3) ◽  
pp. 163 ◽  
Author(s):  
BOZENA KOLANO ◽  
JAMIE McCANN ◽  
MAJA OSKĘDRA ◽  
MARCELINA CHRAPEK ◽  
MAGDALENA ROJEK ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Analyses ◽  
5S Rdna ◽  
The Other ◽  
Parental Origin ◽  
B Genome ◽  
Rdna Loci ◽  
History Of ◽  
35S Rdna

Hybridization and polyploidization appear to be ubiquitous in the evolution of Chenopodium s.s., but the origin and the evolutionary history of the polyploid chenopods is still poorly understood. Phylogenetic analyses of DNA sequences of nrITS, four plastid regions, and 5S rDNA spacer region (NTS) of five Eurasian hexaploid chenopods (2n = 6x = 54), C. album, C. giganteum, C. pedunculare C. formosanum and C. opulifolium, and their diploid and tetraploid relatives as well as genomic in situ hybridization (GISH) indicate their allohexaploid origin. The origin of all the analyzed hexaploids have been inferred to have involved B-genome diploid. The identity of the other parent/parents is more elusive. In the case of C. album, C. giganteum and C. pedunculare the second maternal parent seems to be similar to extant C. strictum or C. striatiforme or Asian diploids (e.g. C. acuminatum). In genomes of allohexaploid C. album, C. giganteum and C. pedunculare half of the rDNA were located in the chromosomes of B-subgenome. The remaining rDNA loci were placed in chromosomes originating from the other parent/parents. Although 35S rDNA loci inherited from two parental species seems to be present in these hexaploids, only one ribotype of nrITS was detected.

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