Ryukyu spiny rats (genus Tokudaia), which are endemic to the central part of the Nansei Shoto archipelago in Japan, have unique karyotypes with odd numbers of chromosomes and no cytologically recognizable Y chromosome. The chromosome numbers of Tokudaia osimensis from Amamioshima and of Tokudaia sp. from Tokunoshima are 2n = 25 and 2n = 45, respectively, with a putative single X chromosome. The mouse X probe hybridized to the unpaired X chromosome, except for the distal part of the short arm in a female specimen of T. osimensis and in one male and one female of Tokudaia sp. Fluorescence in situ hybridization with the Tspy (testis-specific protein, Y-encoded) gene from both male and female cells of Tokudaia sp. by PCR localized Tspy to the distal part of the long arm of the X chromosome. Another Y-related gene, Zfy, from Tokudaia sp. was also localized to the same region in both species. Although the Sry gene is absent in this species, the present results suggest that the Y-chromosome segment carrying functional Y-linked genes, such as Tspy and Zfy, is translocated onto the distal part of the long arm of the X chromosome.   

1.
Bardoni B, Zanaria E, Guioli S, Floridia G, Worley KC, Tonini G, Ferrante E, Chiumello G, McCabe ER, Fraccaro M, et al: A dosage sensitive locus at chromosome Xp21 is involved in male to female sex reversal. Nature Genet 7:497–501 (1994).
2.
Baumstark A, Akhverdyan M, Schulze A, Reisert I, Vogel W, Just W: Exclusion of SOX9 as the testis determining factor in Ellobius lutescens: evidence for another testis determining gene besides SRY and SOX9. Mol Genet Metab 72:61–66 (2001).
3.
Dechend F, Schubert S, Nanda I, Vogel T, Schmid M, Schmidtke J: Organization and expression of rat Tspy. Cytogenet Cell Genet 83:270–274 (1998).
4.
Graves JAM: The rise and fall of SRY. Trends Genet 18:259–264 (2002).
5.
Honda T, Suzuki H, Itoh M: An unusual sex chromosome constitution found in the Amami spinous country-rat, Tokudaia osimensis osimensis. Jpn J Genet 52:247–249 (1977).
6.
Honda T, Suzuki H, Itoh M, Hayashi K: Karyotypical differences of the Amami spinous country-rats, Tokudaia osimensis osimensis obtained from two neighbouring islands. Jpn J Genet 53:297–299 (1978).
7.
International Union for the Conservation of Nature: 2000 IUCN Red List of Threatened Species (International Union for the Conservation of Nature, Gland/Cambridge 2000).
8.
Just W, Rau W, Vogel W, Akhverdian M, Fredga K, Graves JAM, Lyapunova E: Absence of Sry in species of the vole Ellobius. Nature Genet 11:117–118 (1995).
9.
Kaneko Y: Morphological discrimination of the Ryukyu spiny rat (genus Tokudaia) between the islands of Okinawa and Amami Oshima, in the Ryukyu Islands, southern Japan. Mammal Study 26:17–33 (2001).
10.
Kawamura Y: Quaternary Rodent Faunas in the Japanese Islands, Pt 2. Memoirs of the Faculty of Science, Kyoto University, Series of Geology and Mineralogy, Vol 54, pp 1–235 (1989).
11.
Kominami R, Mishima Y, Urano Y, Sakai M, Muramatsu M: Cloning and determination of the transcription termination site of ribosomal RNA gene of the mouse. Nucl Acids Res 10:1963–1979 (1982).
12.
Koopman P, Gubbay J, Vivian N, Goodfellow P, Lovell-Badge R: Male development of chromosomally female mice transgenic for Sry. Nature 351:117–121 (1991).
13.
Kurihara Y, Suh D-S, Suzuki H, Moriwaki K: Chromosome locations of Ag-NORs and clusters of ribosomal DNA in laboratory strains of mouse. Mammal Genome 5:225–228 (1994).
14.
Kuroiwa A, Watanabe T, Hishigaki H, Takahashi E, Namikawa T, Matsuda Y: Comparative FISH mapping of mouse and rat homologues of twenty-five human X-linked genes. Cytogenet Cell Genet 81:208–212 (1998).
15.
Lahn BT, Page DC: Four evolutionary strata on the human X chromosome. Science 286:964–967 (1999).
16.
Matsuda Y, Chapman VM: Application of fluorescence in situ hybridization in genome analysis of the mouse. Electrophoresis 16:261–272 (1995).
17.
Matsuda Y, Harada YN, Natsuume-Sakai S, Lee K, Shiomi T, Chapman VM: Location of the mouse complement factor H gene (cfh) by FISH analysis and replication R-banding. Cytogenet Cell Genet 61:282–285 (1992).
18.
Michaux JR, Chevret P, Filippucci MG, Macholan M: Phylogeny of the genus Apodemus with a special emphasis on the subgenus Sylvaemus using the nuclear IRBP gene and two mitochondrial markers: cytochrome b and 12S rRNA. Mol Phylogenet Evol 23:123–136 (2002).
19.
Ohno S: Sex Chromosomes and Sex-Linked Genes (Springer-Verlag, Berlin 1967).
20.
Schnieders F, Dork T, Arnemann J, Vogel T, Werner M, Schmidtke J: Testis-specific protein, Y-encoded (TSPY) expression in testicular tissues. Hum molec Genet 5:1801–1807 (1996).
21.
Sinclair AH, Berta P, Palmer MS, Hawkins JR, Griffiths BL, Smith MJ, Foster JW, Frischauf AM, Lovell-Badge R, Goodfellow PN: A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif. Nature 346:240–244 (1990).
22.
Soullier S, Hanni C, Catzeflis F, Berta P, Laudet V: Male sex determination in the spiny rat Tokudaia osimensis (Rodentia: Muridae) is not Sry dependent. Mammal Genome 9:590–592 (1998).
23.
Sumner AT: A simple technique for demonstrating centromeric heterochromatin. Expl Cell Res 75:304–306 (1972).
24.
Sutou S, Mitsui Y, Tsuchiya K: Sex determination without the Y chromosome in two Japanese rodents, Tokudaia osimensis and Tokudaia osimensis spp. Mammal Genome 12:17–21 (2001).
25.
Suzuki H, Iwasa MA, Ishii N, Nagaoka H, Tsuchiya K: The genetic status of two insular populations of the endemic spiny rat Tokudaia osimensis (Rodentia, Muridae) of the Ryukyu Islands, Japan. Mammal Study 24:43–50 (1999).
26.
Suzuki H, Tsuchiya K, Takezaki N: A molecular phylogenetic framework for the Ryukyu endemic rodents Tokudaia osimensis and Diplothrix legata (Muridae: Murinae). Mol Phylogenet Evol 15:15–24 (2000).
27.
Swain A, Narvaez V, Burgoyne P, Camerino G, Lovell-Badge R: Dax1 antagonizes Sry action in mammalian sex determination. Nature 39:761–776 (1998).
28.
Tsuchiya K, Wakana S, Suzuki H, Hattori S, Hayashi Y: Taxonomic study of Tokudaia (Rodentia: Muridae). I. Genetic differentiation [in Japanese with English summary]. Memoirs of the National Science Museum, Tokyo, Vol 22, pp 227–234 (1989).
29.
Vogel W, Jainta S, Rau W, Geerkens C, Baumstark A, Correa-Cerro LS, Ebenhoch C, Just W: Sex determination in Ellobius lutescens: the story of an enigma. Cytogenet Cell Genet 80:214–221 (1998).
30.
Xiao C, Tsuchiya K, Sutou S: Cloning and mapping of bovine ZFX gene to the long arm of the X-chromosome (Xq34) and homologous mapping of ZFY gene to the distal region of the short arm of the bovine (Yp13), ovine (Yp12-p13), and caprine (Yp12-p13) Y chromosome. Mammal Genome 9:125–130 (1998).
31.
Yoshida MC, Ikeuchi T, Sasaki M: Differential staining of parental chromosomes in interspecific cell hybrids with a combined quinacrine and 33258 Hoechst technique. Proc Jpn Acad 51:184–187 (1975).
© 2003 S. Karger AG, Basel
2003
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.