Dioecy is relatively rare in plants and sex determination systems vary among such species. A good example of a plant with heteromorphic sex chromosomes is hop (Humulus lupulus). The genotypes carrying XX or XY chromosomes correspond to female and male plants, respectively. Until now no clear cytogenetic markers for the sex chromosomes of hop have been established. Here, for the first time the sex chromosomes of hop are clearly identified and characterized. The high copy sequence of hop (HSR1) has been cloned and localized on chromosomes by fluorescence in situ hybridization. The HSR1 repeat has shown subtelomeric location on autosomes with the same intensity of the signal. The signal has been present in the subtelomeric region of the long arm and in the near-centromeric region but absent in the telomeric region of the short arm of the X chromosome. At the same time the signal has been found in the telomeric region only of the long arm of the Y chromosome. This finding indicates that the sex chromosomes of hop have evolved from a pair of autosomes via ancient translocation or inversion. The observation of the meiotic configuration of the sex bivalents shows the location of a pseudoautosomal region on the long arms of X and Y chromosomes.

Armstrong SJ, Filatov DA: A cytogenetic view of sex chromosome evolution in plants. Cytogenet Genome Res 120:241–246 (2008).
Badge RM, Yardley J, Jeffreys AJ, Armour JA: Crossover breakpoint mapping identifies a subtelomeric hotspot for male meiotic recombination. Hum Mol Genet 9:1239–1244 (2000).
Bridges CB: Triploid intersexes in Drosophila melanogaster. Science 54:252–254 (1921).
Bůzek J, Koutníková H, Houben A, Ríha K, Janousek B, et al: Isolation and characterization of X chromosome-derived DNA sequences from a dioecious plant Melandrium album. Chromosome Res 5:57–65 (1997).
Charlesworth D, Charlesworth B, Marais G: Steps in the evolution of heteromorphic sex chromosomes. Heredity 95:118–128 (2005).
Cuadrado A, Golczyk H, Jouve N: A novel, simple and rapid nondenaturing FISH (ND-FISH) technique for the detection of plant telomeres. Potential used and possible target structures detected. Chromosome Research 17:755–762 (2009).
Dellaporta SL, Calderon-Urrea A: Sex determination in flowering plants. Plant Cell 5:1241–1251 (1993).
Dobigny G, Ducroz JF, Robinson TJ, Volobuev V: Cytogenetics and Cladistics. Syst Biol 53:470–484 (2004).
Fesenko IA, Khrustaleva LI, Karlov GI: Organization of the 378-bp satellite repeat in terminal heterochromatin of Allium fistulosum. Russ J Genet 38:745–753 (2002).
Galasso I, Schmidt T, Pignone D: Identification of Lens culinaris ssp. culinaris chromosomes by physical mapping of repetitive DNA sequences. Chromosome Res 9:199–209 (2001).
Garrido-Ramos MA, de la Herrán R, Ruiz Rejón M, Ruiz Rejón C: A subtelomeric satellite DNA family isolated from the genome of the dioecious plant Silene latifolia. Genome 42:442–446 (1999).
Gerlach WL, Bedbrook JR: Cloning and characterization of ribosomal RNA genes from wheat and barley. Nucl Acids Res 7:1869–1885 (1979).
Grabowska-Joachimiak A, Mosiolek M, Lech A., Goralski G: C-Banding/DAPI and in situ hybridization reflect karyotype structure and sex chromosome differentiation in Humulus japonicus Siebold & Zucc. Cytogenet Genome Res 132:203–211 (2011).
Heslop-Harrison JS, Murata M, Ogura Y, Schwarzacher T, Motoyoshi F: Polymorphisms and genomic organization of repetitive DNA from centromeric regions of Arabidopsis chromosomes. Plant Cell 11:31–42 (1999).
Jamilena M, Mariotti B, Manzano S: Plant sex chromosomes: molecular structure and function. Cytogenet Genome Res 120:255–264 (2008).
Karlov GI, Danilova TV, Horlemann C, Weber G: Molecular cytogenetics in hop (Humulus lupulus L.) and identification of sex chromosomes by DAPI-banding. Euphytica 132:185–190 (2003).
Kazama Y, Sugiyama R, Matsunaga S, Shibata F, Uchida Y, et al: Organization of the Kpn I family of chromosomal distal-end satellite DNA in Silene latifolia. J Plant Res 116:317–326 (2003).
Kazama Y, Sugiyama R, Suto Y, Uchida W, Kawano S: The clustering of four subfamilies of satellite DNA at individual chromosome ends in Silene latifolia. Genome 49:520–530 (2006).
Kejnovsky E, Hobza R, Cermak T, Kubat Z, Vyskot B: The role of repetitive DNA in structure and evolution of sex chromosomes in plants. Heredity 102:533–541 (2009).
Koo DH, Hur YK, Bang JW: Variability of rDNA loci in dioecious Rumex acetosa L. detected by fluorescence in situ hybridization. Korean J Genet 26:9–13 (2004).
Koo DH, Nam YW, Choi D, Bang JW, de Jong H, Hur Y: Molecular cytogenetic mapping of Cucumis sativus and C. melo using highly repetitive DNA sequences. Chromosome Res 18:325–336 (2010).
Kuo H, Olsen KM, Richards EJ: Natural variation in a subtelomeric region of Arabidopsis: implications for the genomic dynamics of a chromosome end. Genetics 173:401–417 (2006).
Lee WK, Choi HW, Koo DH, Kim SY, Bang JW: Molecular cytogenetics of five Pulsatilla species to the 5S, 45S rDNA genes by fluorescence in situ hybridization. Korean J Genet 27:179–185 (2005).
Lengerova M, Moore RC, Grant SR, Vyskot B: The sex chromosomes of Silene latifolia revisited and revised. Genetics 165:935–938 (2003).
Levan A, Fredga K, Sandberg A: Nomenclature for centromeric position on chromosomes. Hereditas 52:201–220 (1964).
Lundblad V, Blackburn EH: An alternative pathway for yeast telomere maintenance rescues est1-senescence. Cell 73:347–360 (1993).
Matsunaga S, Kawano S, Michimoto T: Semi-automatic laser beam microdissection of the Y chromosome and analysis of Y chromosome DNA in a dioecious plant Silene latifolia. Plant Cell Physiol 40:60–68 (1999).
Mefford HC, Trask BJ: The complex structure and dynamic evolution of human subtelomeres. Nat Rev Genet 3:91–102 (2002).
Ming R, Wang J, Moore PH, Paterson AH: Sex chromosomes in flowering plants. Am J Bot 94:141–150 (2007).
Navajas-Pérez R, Schwarzacher T, Ruiz-Rejón M, Garrido-Ramos MA: Characterization of RUSI, a telomere-associated satellite DNA, in the genus Rumex (Polygonaceae). Cytogenet Genome Res 124:81–89 (2009).
Negrutiu I, Vyskot B, Barbacar N, Georgiev S, Moneger F: Dioecious plants. A key to the early events of sex chromosome evolution. Plant Physiol 127: 1418–1424 (2001).
Neve RA: Sex determination in the cultivated hop Humulus lupulus. PhD thesis, University of London (1961).
Neve RA: Hops (Chapman and Hall, London 1991).
Ono T: Chromosomes of common hop and its relatives. Bull Brew Sci 2:3–65 (1955).
Parker JS, Clark MS: Dosage sex-chromosome systems in plants. Plant Sci 80:79–92 (1991).
Raina S, Sharma S, Sasakuma T, Kishii M, Vaishnavi S: Novel repeated DNA sequences in safflower (Carthamus tinctorius L.) (Asteraceae): cloning, sequencing, and physical mapping by fluorescence in situ hybridization. J Hered 96:424–429 (2005).
Rogers SO, Bendich AJ: Extraction of DNA from milligram amounts of fresh, herbarium and mummified plant tissues. Plant Mol Biol Rep 5:69–76 (1985).
Sakamoto K, Shimomura K, Komeda Y, Kamada H, Satoh S: A male-associated DNA sequence in a dioecious plant, Cannabis sativa L. Plant Cell Physiol 36:1549–1554 (1995).
Shephard HL, Parker JS, Darby P, Ainsworth CC: Sexual development and sex chromosomes in hop. New Phytol 148:397–411 (2000).
Shibata F, Hizume M, Kuroki Y: Molecular cytogenetic analysis of supernumerary heterochromatic segments on Rumex acetosa. Genome 43:391–397 (2000).
Sinoto Y: Chromosome studies in some dioecious plants, with special reference to allosomes. Cytologia 1:109–191 (1929).
Wang SS, Zakian VA: Telomere-telomere recombination provides an express pathway for telomere acquisition. Nature 345:456–458 (1990).
Westergaard M: Studies on cytology and sex determination in polyploid forms of Melandrium album. Dan Bot Ark 10:1–131 (1940).
Winge Ö: On the nature of sex chromosome in Humulus. Hereditas 12:53–63 (1929).
Zanoli P, Zavatti M: Pharmacognostic and pharmacological profile of Humulus lupulus L. J Ethnopharmacol 116:383–396 (2008).
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.