Molecular Biotechnology

, Volume 25, Issue 2, pp 149–184 | Cite as

Genomic imprinting and endosperm development in flowering plants

  • Rinke Vinkenoog
  • Catherine Bushell
  • Melissa Spielman
  • Sally Adams
  • Hugh G. Dickinson
  • Rod J. Scott


Genomic imprinting, the parent-of-origin-specific expression of genes, plays an important role in the seed development of flowering plants. As different sets of genes are imprinted and hence silenced in maternal and paternal gametophyte genomes, the contributions of the parental genomes to the offspring are not equal. Imbalance between paternally and maternally imprinted genes, for instance as a result of interploidy crosses, or in seeds in which imprinting has been manipulated, results in aberrant seed development. It is predominantly the endosperm, and not or to a far lesser extent the embryo, that is affected by such imbalance. Deviation from the normal 2m:1p ratio in the endosperm genome has a severe effect on endosperm development, and often leads to seed abortion. Molecular expression data for imprinted genes suggest that genomic imprinting takes place only in the endosperm of the developing seed. Although far from complete, a picture of how imprinting operates in flowering plants has begun to emerge. Imprinted genes on either the maternal or paternal side are marked and silenced in a process involving DNA methylation and chromatin condensation. In addition, on the maternal side, imprinted genes are most probably under control of the polycomb FIS genes.

Index Entries

Genomic imprinting epigenetics endosperm seed development apomixis FIS polycomb interploidy crosses interspecific hybridization 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Surani, M. A., Kothary, R., Allen, N. D., et al. (1990) Genome imprinting and development in the mouse. Development Suppl., 89–98.Google Scholar
  2. 2.
    Mertineit, C., Yoder, J.A., Taketo, T., et al. (1998) Sexspecific exons control DNA methyltransferase in mammalian germ cells. Development 125, 889–897.PubMedGoogle Scholar
  3. 3.
    Brannan, C.I. and Bartolomei, M.S. (1999) Mechanisms of genomic imprinting. Currt. Opin. Genet. Dev. 9, 164–170.CrossRefGoogle Scholar
  4. 4.
    Haig, D. and Westoby, M. (1989) Parent-specific gene expression and the triploid endosperm. Am. Naturalist 134, 147–155.CrossRefGoogle Scholar
  5. 5.
    Haig, D. and Westoby, M. (1991) Genomic imprinting in endosperm: its effect on seed development in crosses between species, and between different ploidies of the same species, and its implications for the evolution of apomixis. Phil. Trans. R. Soc. Lond. [B] 333, 1–13.CrossRefGoogle Scholar
  6. 6.
    Tilghman, S.M. (1999) The sins of the fathers and mothers: genomic imprinting inmammalian development. Cell 96, 185–193.PubMedCrossRefGoogle Scholar
  7. 7.
    Georgiades, P., Watkins, M., Burton, G.J., and Ferguson-Smith, A.C. (2001) Roles for genomic imprinting and the zygotic genome in placental development. Proc. Natl. Acad. Sci. USA 98, 4522–4527.PubMedCrossRefGoogle Scholar
  8. 8.
    The Genomic Imprinting Website:http://www.geneimprint.comGoogle Scholar
  9. 9.
    Li, E., Bestor, T.H. and Jaenisch, R. (1992) Targeted mutation of the DNA methyltranferase gene results in embryonic lethality. Cell 69, 915–926.PubMedCrossRefGoogle Scholar
  10. 10.
    Li, E., Beard, C. and Jaenisch, R. (1993) Role for DNA methylation in genomic imprinting. Nature 366, 362–365.PubMedCrossRefGoogle Scholar
  11. 11.
    Adams, S., Vinkenoog, R., Spielman, M., et al. (2000) Parental imprinting in Arabidopsis requires DNA methylation. Development 127, 2493–2502.PubMedGoogle Scholar
  12. 12.
    Bender, J. (2002) Plant epigenetics. Curr. Biol. 12, R412-R414.PubMedCrossRefGoogle Scholar
  13. 13.
    Köhler, C. and Grossniklaus, U. (2002) Epigenetics: The flowers that come in from the cold. Curr. Biol. 12, R129-R131.PubMedCrossRefGoogle Scholar
  14. 14.
    Grossniklaus, U., Spillane, C., Page, D.R., and Köhler, C. (2001) Genomic imprinting and seed development: Endosperm formation with and without sex. Curr. Opin. Plant Biol. 4, 21–27.PubMedCrossRefGoogle Scholar
  15. 15.
    Baroux, C.S., Spillane, C., and Grossniklaus, U. (2002) Genomic imprinting during seed development. Adv. Genet. 46, 165–214.PubMedGoogle Scholar
  16. 16.
    Chaudhury, A.M., Koltunow, A., Payne, T., et al. (2001) Control of early seed development. Ann. Rev. Cell Dev. Biol. 17, 677–699.CrossRefGoogle Scholar
  17. 17.
    Lohe, A.R. and Chaudhury, A. (2002) Genetic and epigenetic processes in seed development. Curr. Opin. Plant Biol. 5, 19–25.PubMedCrossRefGoogle Scholar
  18. 18.
    Chaudhury, A.M. and Berger, F. (2001) Maternal control of seed development. Semin. Cell Dev. Biol. 12, 381–386.PubMedCrossRefGoogle Scholar
  19. 19.
    Kaufman, M.H., Barton, S.C. and Surani, M.A. (1977) Normal postimplantation development of mouse parthenogenetic embryos to the forelimb bud stage. Nature 265, 53–55.PubMedCrossRefGoogle Scholar
  20. 20.
    Barton, S.C., Surani, M.A., and Norris, M.L. (1984) Role of paternal and maternal genomes in mouse development. Nature 311, 374–376.PubMedCrossRefGoogle Scholar
  21. 21.
    Surani, M.A.H., Barton, S.C. and Norris, M.L. (1984) Development of reconstituted mouse eggs suggests imprinting of the genome during gametogenesis. Nature 308, 548–550.PubMedCrossRefGoogle Scholar
  22. 22.
    McGrath, J. and Solter, D. (1984) Completion of mouse embryogenesis requires both the maternal and paternal genomes. Cell 37, 179–183.PubMedCrossRefGoogle Scholar
  23. 23.
    Surani, M.A.H., Barton, S.C., and Norris, M.L. (1986) Nuclear transplantation in the mouse: heritable differences between maternal and paternal genomes after activation of the embryonic genome. Cell 45, 127–136.PubMedCrossRefGoogle Scholar
  24. 24.
    Thomson, J.A. and Solter, D. (1988) The developmental fate of androgenetic, parthenogenetic and gynogenetic cells in chimeric gastrulating mouse embryos. Genes Dev. 2, 1344–1351.PubMedCrossRefGoogle Scholar
  25. 25.
    Surani, M.A.H., Barton, S.C., and Norris, M.L. (1987) Influence of parental chromosomes on spatial specificity in androgenetic vs. parthenogenetic chimaeras in the mouse. Nature 326, 395–397.PubMedCrossRefGoogle Scholar
  26. 26.
    Nagy, A., Paldi, A., Dezso, L., et al. (1987) Prenatal fate of parthenogenetic cells in mouse aggregation chimeras. Development 101, 67–71.PubMedGoogle Scholar
  27. 27.
    Schwere, S. (1896) Zur Entwicklungsgeschichte der Frucht von Taraxacum officinale Web.; ein Beitrag zur Embryologie der Compositen. Flora Bildung, Marburg, Germany 82, 32–66, Taf. II–V.Google Scholar
  28. 28.
    Raunkiær, C. (1903) Kimdannelse uden Befrugtning hos Mælkebøtte (Taraxacum). Bot. Tidsskr. 25, 110–140.Google Scholar
  29. 29.
    Murbeck, S. (1904) Parthenogenese bei den Gattungen Taraxacum und Hieracium. Bot. Not. 6, 285–296.Google Scholar
  30. 30.
    Rutishauser, A. (1954) Entwicklungserregung der Eizelle bei pseudogamen Arten der Gattung Ranunculus. [German, with English, Italian and French summary]. Bull. Schweiz.Akad. Med. Wissensch. 10, 491–512.Google Scholar
  31. 31.
    Rutishauser, A. (1967) Fortpflanzungsmodus und Meiose apomiktischer Blütenpflanzen. Protoplasmatologia 6/3, 3–243.Google Scholar
  32. 32.
    Richards, A.J. (1970) Eutriploid facultative agamospermy in Taraxacum. New Phytol. 69, 761–774.CrossRefGoogle Scholar
  33. 33.
    Richards, A.J. (1973) The origin of Taraxacum agamospecies. Bot. J. Linn. Soc. 66, 189–211.Google Scholar
  34. 34.
    Pogan, E. and Wcislo, H. (1995) Embryological analysis of Hieracium pilosella L. from Poland. Acta Biol. Cracov. Series Botanica 37, 53–61.Google Scholar
  35. 35.
    Bruun, L. (1991) Histological and semiquantitative approaches to in vitro cellular-responses of ovule, embryo and endosperm in sugar beet, Beta vulgaris L. Sex. Plant Reprod. 4, 64–7.2CrossRefGoogle Scholar
  36. 36.
    Ferrant, V. and Bouharmont, J. (1994) Origin of gynogenetic embryos of Beta vulgaris L. Sex. Plant Reprod. 7, 12–16.CrossRefGoogle Scholar
  37. 37.
    Hansen, A.L., Gertz, A. and Joersbo, M. (1995) Short-duration colchicine treatment for in vitro chromosome doubling during ovule culture of Beta vulgaris L. Plant Breed. 114, 515–519.CrossRefGoogle Scholar
  38. 38.
    Miyoshi, K. and Asakura, N. (1996) Callus induction, regeneration of haploid plants and chromosome doubling in ovule cultures of pot gerbera (Gerbera jamesonii). Plant Cell Rep. 16, 1–5.CrossRefGoogle Scholar
  39. 39.
    Mdarhri-Alaoui, M., Saidi, N., et al. (1998) Green haploid plant formation in durum wheat through in vitro gynogenesis. CR Acad. Sci. III (Sciences de la V.) (Paris) 321, 25–30.Google Scholar
  40. 40.
    Michalik, B., Adamus, A. and Nowak, E. (2000) Gynogenesis in Polish onion cultivars. J. Plant Physiol. 156, 211–216.Google Scholar
  41. 41.
    Clapham, D. (1971) In vitro development of callus from the pollen of Lolium and Hordeum. Z. Pflanzenzüchtg 65, 285–292.Google Scholar
  42. 42.
    Ouyang, K.H., Hu, H., Chuang, C.C. and Tseng, C.-C. (1973) Induction of pollen plants from anthers of Triticum aestivum L. cultured in vitro. Scient. Sinica. 16, 79–95.Google Scholar
  43. 43.
    Pretova, A., de Ruijter, N.C.A., van Lammeren, A.A.M. and Schel, J.H.N. (1993) Structural observations during androgenic microspore culture of the 4C1 genotype of Zea mays L. Euphytica 65, 61–69.CrossRefGoogle Scholar
  44. 44.
    Bulk, R.W. van den, de Vries van Hulten, H.P.J., Custers, J.B.M. and Dons, J.J.M. (1994) Induction of embryogenesis in isolated microspores of tulip. Plant Sci. 104, 101–111.CrossRefGoogle Scholar
  45. 45.
    Binarova, P., Hause, G., Genklova, V., et al. (1997) A short severe heat shock is required to induce embryogenesis in late bicellular pollen of Brassica napus L. Sex. Plant Reprod. 10, 200–208.CrossRefGoogle Scholar
  46. 46.
    Atanassov, A., Zagorska, N, Boyadjiev, P. and Djilianov, D. (1995) In-vitro production of haploid plants. World J. Microbiol. Biotechnol. 11, 400–408.CrossRefGoogle Scholar
  47. 47.
    Raghavan, V. (1976) Role of the generative cell in androgenesis in henbane. Science 191, 388–389.CrossRefPubMedGoogle Scholar
  48. 48.
    Tyukavin, G.B., Shmykova, N.A. and Monakhova, M.A. (1999) Cytological study of embryogenesis in cultured carrot anthers. Russ. J. Plant Physiol. 46, 767–773.Google Scholar
  49. 49.
    Richards, A.J. (1986) Plant Breeding Systems. George Allen and Unwin, London.Google Scholar
  50. 50.
    Sterk, A.A., Hommels, C.H., Jenniskens, M.J.P.J., et al. (1987) Paardebloemen-Planten Zonder Vader. Koninklijke Nederlandse Natuurhistorische Vereniging, Utrecht, The Netherlands.Google Scholar
  51. 51.
    Friedman, W.E. (1995) Organismal duplication, inclusive fitness theory, and altruism—understanding the evolution of endosperm and the angiosperm reproductive syndrome. Proc. Natl. Acad. Sci. USA 92, 3913–3917.PubMedCrossRefGoogle Scholar
  52. 52.
    Friedman, W.E. (1998) The evolution of double fertilization and endosperm: an “historical” perspective. Sex. Plant Reprod. 11, 6–16.CrossRefGoogle Scholar
  53. 53.
    Friedman, W.E. (2001) Developmental and evolutionary hypotheses for the origin of double fertilization and endosperm. CR Acad. Sci. Sciences De La V.) (Paris) 324, 559–567.Google Scholar
  54. 54.
    Chaw, S.M., Parkinson, C.L., Cheng, Y., et al. (2000) Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers. Proc. Natl. Acad. Sci. USA 97, 4086–4091.PubMedCrossRefGoogle Scholar
  55. 55.
    Bowe, L.M., Coat, G., and dePamphilis, C.W. (2000) Phylogeny of seed plants based on all three genomic compartments: Extant gymnosperms are monophyletic and Gnetales’ closest relatives are conifers. Proc. Natl. Acad. Sci. USA 7, 4092–4097.CrossRefGoogle Scholar
  56. 56.
    Baroux, C., Spillane, C., and Grossniklaus, U. (2002) Evolutionary origins of the endosperm in flowering plants. Genome Biol. 3, 1026.1–1026.5CrossRefGoogle Scholar
  57. 57.
    Schulz, P. and Jensen, W.A. (1974) Capsella embryogenesis: The development of the free nuclear endosperm. Protoplasma 80, 183–205.CrossRefGoogle Scholar
  58. 58.
    Bhatnagar, S.P. and Sawhney, V. (1981) Endosperm—its morphology, ultrastructure, and histochemistry. Int. Rev. Cytol. 73, 55–102.Google Scholar
  59. 59.
    Lopes, M. A. and Larkins, B. A. (1993) Endosperm origin, development, and function. Plant Cell 5, 1383–1399.PubMedCrossRefGoogle Scholar
  60. 60.
    Berger, F. (1999) Endosperm development. Curr. Opin. Plant Biol. 2, 28–32.PubMedCrossRefGoogle Scholar
  61. 61.
    Schulz, P. and Jensen, W.A. (1971). Capsella embryogenesis: the chalazal proliferating tissue. J. Cell Sci. 8, 201–227.PubMedGoogle Scholar
  62. 62.
    Mansfield, S.G. and Briarty, L.G. (1990) Development of the free-nuclear endosperm in Arabidopsis thaliana (L.). Arabidopsis Inf. Serv. 27. Google Scholar
  63. 63.
    Mansfield, S.G. (1994) Endosperm development. In: Arabidopsis, An Atlas of Morphology and Development. (Bowman, J., ed.), Springer Verlag, Berlin-Heidelberg, New York. pp. 385–397.Google Scholar
  64. 64.
    Håkansson, A. (1956) Seed development of Brassica oleracea and B. rapa after certain reciprocal pollinations. Hereditas 42, 373–396.CrossRefGoogle Scholar
  65. 65.
    Mansfield, S.G., Briarty, L.G. and Erni, S. (1991) Early embryogenesis in Arabidopsis thaliana. I. The mature embryo sac. Can. J. Bot. 69, 447–460.Google Scholar
  66. 66.
    Chamberlin, M.A., Horner, H.T., and Palmer, R.G. (1993) Nutrition of the ovule, embryo sac, and young embryo in soybean: An anatomical and autoradiographic study. Can. J. Bot. 71, 1152–1168.Google Scholar
  67. 67.
    Brink, R.A. and Cooper, D.C. (1947) The endosperm in seed development. Bot. Rev. 13, 423–541.Google Scholar
  68. 68.
    Maheswari, P. (1950) An Introduction to the Embryology of the Angiosperms. NY: McGraw-Hill, New York, pp. 221–267.Google Scholar
  69. 69.
    Vijayaraghavan, M.R. and Prabhakar, K. (1984) The endosperm. In: Embryology of Angiosperms. (Johri, B.M., ed.), Springer Verlag, Berlin, pp. 319–376.Google Scholar
  70. 70.
    Boisnard-Lorig, C., Colon-Carmona, A., Bauch, M., et al. (2001) Dynamic analyses of the expression of the HISTONE:: YFP fusion protein in Arabidopsis show that syncytial endosperm is divided in mitotic domains. Plant Cell 13, 495–509.PubMedCrossRefGoogle Scholar
  71. 71.
    Mansfield, S.G. and Briarty, L.G. (1990) Endosperm cellularization in Arabidopsis thaliana L. Arabidopsis Inf. Serv. 27. Available at Scholar
  72. 72.
    Brown, R. C., Lemmon, B. E., Nguyen, H., and Olsen, O.-A. (1999) Development of endosperm in Arabidopsis thaliana. Sex. Plant Reprod. 12, 32–42.CrossRefGoogle Scholar
  73. 73.
    Marinos, N.G. (1970) Embryogenesis of the pea (Pisum sativum). I. The cytological environment of the developing embryo. Protoplasma 70, 261–279.CrossRefGoogle Scholar
  74. 74.
    Müntzing, A. (1930) Über Chromosomenvermehrung in Galeopsis-Kreuzungen und ihre phylogenetische Bedeutung. Hereditas (Lund) 14, 153–172.CrossRefGoogle Scholar
  75. 75.
    Müntzing, A. (1933) Hybrid incompatibility and the origin of polyploidy. Hereditas (Lund) 18, 33–55.CrossRefGoogle Scholar
  76. 76.
    Watkins, A.E. (1932) Hybrid sterility and incompatibility. J. Genet. 25, 125–162.Google Scholar
  77. 77.
    Howard, H.W. (1939) The size of seeds in diploid and autotetraploid Brassica oleracea L. J. Genet. 38, 325–340.Google Scholar
  78. 78.
    Cooper, D.C. and Brink, R.A. (1945) Seed collpase following matings between diploid and tetraploid races of Lycopersicon pimpinellifolium. Genetics 30, 376–401.PubMedGoogle Scholar
  79. 79.
    Cooper, D.C. (1951) Caryopsis development following matings between diploid and tetraploid strains in Zea mays. Am. J. Bot. 38, 702–708.CrossRefGoogle Scholar
  80. 80.
    Håkansson, A. (1952) Seed development after 2x, 4x crosses in Galeopsis pubescens. Hereditas 38, 425–448.CrossRefGoogle Scholar
  81. 81.
    Håkansson, A. (1953) Endosperm formation after 2x, 4x crosses in certaincereals, especially in Hordeum vulgare. Hereditas 39, 57–64.CrossRefGoogle Scholar
  82. 82.
    Håkansson, A. and Ellerström, S. (1950) Seed development after reciprocal crosses between diploid and tetraploid rye. Hereditas 36, 256–296.CrossRefGoogle Scholar
  83. 83.
    Fagerlind, F. (1937) Embryologische, zytologische und bestäubungsexperimentelle Studien in der Familie Rubiaceae nebst Bemerkungen über einige Polyploiditätsprobleme. Acta Horti Bergiana 11, 195–470.Google Scholar
  84. 84.
    Boyes, J.W. and Thompson, W.P. (1937) The development of the endosperm and embryo in reciprocal interspecific crosses in cereals. J. Genet. 34, 203–207.Google Scholar
  85. 85.
    Kihara, H. and Nishiyama, I. (1932) Different compatibility in reciprocal crosses of Avena with special reference to tetraploid hybrids between hexaploid and diploid species. Jpn. J. Bot. 6, 245–305.Google Scholar
  86. 86.
    von Wangenheim, K.-H. (1962) Zur Ursache der Abortion von Samenanlagen in Diploid-Polyploid-Kreuzungen. II. Unterschiedliche Differenzierung von Endospermen mit gleichem Genom. Zeitschr. Vererbungsehre 93, 319–334.CrossRefGoogle Scholar
  87. 87.
    Nishiyama, I. and Inomata, N. (1966) Embryological studies on cross-incompatibility between 2x and 4x in Brassica. Jpn. Genet. 41, 27–42.Google Scholar
  88. 88.
    Sarkar, K.R. and Coe, E.H., Jr. (1971) Anomalous fertilisation in diploid-tetraploid crosses in maize. Crop Sci. 11, 539–542.CrossRefGoogle Scholar
  89. 89.
    Kermicle J.L. (1971) Pleiotropic effects on seed development of the indeterminate gametophyte gene in maize. Science 166, 1422–1424.CrossRefGoogle Scholar
  90. 90.
    Lin, B.-Y. (1984) Ploidy barrier to endosperm development in maize. Genetics 107, 103–115.PubMedGoogle Scholar
  91. 91.
    Ehlenfeldt, M.K. and Ortiz, R. (1995) Evidence on the nature and origins of endosperm dosage requirements in Solanum and other angiosperm genera. Sex. Plant Reprod. 8, 189–196.CrossRefGoogle Scholar
  92. 92.
    Thompson, W.P. (1930) Causes of difference in success of reciprocal interspecific crosses. Am. Naturalist 64, 407–421.CrossRefGoogle Scholar
  93. 93.
    Woodell, S.R.J. and Valentine, D.H. (1961) Studies in British primulas. IX. Seed incompatibility in diploid-autotetraploid crosses. New Phytol. 60, 282–294.CrossRefGoogle Scholar
  94. 94.
    Rédei, G. (1964) Crossing experiments with polyploids. Arabidopsis Electronic Information Service 1. Available at httt:// Scholar
  95. 95.
    Scott, R.J., Spielman, M, Bailey, J., and Dickinson, H.G. (1998) Parent-of-origin effects on seed development in Arabidopsis thaliana. Development 125, 3329–3341.PubMedGoogle Scholar
  96. 96.
    Kermicle, J. L. (1970) Dependence of the R-mottled aleurone phenotype in maize on mode of sexual transmission. Genetics 66, 69–85.PubMedGoogle Scholar
  97. 97.
    Lin, B.-Y. (1982) Association of endosperm reduction with parental imprinting in maize. Genetics 100, 475–486.PubMedGoogle Scholar
  98. 98.
    Kermicle, J. L. and Alleman, M. (1990) Gametic imprinting in maize in relation to the angiosperm life cycle. Development Suppl. S. 9–14.Google Scholar
  99. 99.
    Lund, G., Ciceri, P., and Viotti, A. (1995) Maternal-specific demethylation and expression of specific alleles of zein genes in the endosperm of Zea mays L. Plant J. 8, 571–581.PubMedCrossRefGoogle Scholar
  100. 100.
    Lund, G., Messing, J., and Viotti, A. (1995) Endosperm-specific demethylation and activation of specific alleles of alphatubulin genes of Zea mays L. Mol. Gen. Genet. 246, 716–722.PubMedCrossRefGoogle Scholar
  101. 101.
    Abbot, R.J. and Gomes, M.F. (1989) Population genetic structure andoutcrossing rate in Arabidopsis thaliana (L.) Heynh. Heredity 62, 411–418.Google Scholar
  102. 102.
    Stebbins, G.L. (1974) Flowering Plants: Evolution Above the Species Level. Edward Arnold, London.Google Scholar
  103. 103.
    Finnegan, E.J., Peacock, W.J. and Dennis, E.S. (1998) Reduced DNA methylation in plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 49, 223–247.PubMedCrossRefGoogle Scholar
  104. 104.
    Finnegan, E.J., Peacock, W.J., and Dennis, E.S. (1996) Reduced DNA methylation in Arabidopsis thaliana results in abnormal plant development. Proc. Natl. Acad. Sci. USA 93, 8449–8454.PubMedCrossRefGoogle Scholar
  105. 105.
    Blokland, R. van, ten Lohuis, M., and Meyer, P. (1997) Condensation of chromatin in transcriptional regions of an inactivated plant transgene: Evidence for an active role of transcription in gene silencing. Mol. Gen. Genet. 257, 1–13.PubMedCrossRefGoogle Scholar
  106. 106.
    Assaad, F.F. and Signer, E.R. (1992) Somatic and germinal recombination of a direct repeat in Arabidopsis. Genetics 132, 553–566.PubMedGoogle Scholar
  107. 107.
    Ye, F. and Signer, E.R. (1996) RIGS (repeat-induced gene silencing) in Arabidopsis is transcriptional and alters chromatin configuration. Proc. Natl. Acad. Sci. USA 93, 10,881–10,886.CrossRefGoogle Scholar
  108. 108.
    Razin, A. (1998) CpG methylation, chromatin structure and gene silencing — a three way connection. EMBO J. 17, 4905–4908.PubMedCrossRefGoogle Scholar
  109. 109.
    Richards, E.J. and Elgin, S.C.R. (2002) Epigenetic codes for heterochromatin formation and silencing: Rounding up the usual suspects. Cell 108, 489–500.PubMedCrossRefGoogle Scholar
  110. 110.
    Nan, X.S., Ng, H. H., Johnson, C. A., et al. (1998) Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex. Nature 393, 386–389.PubMedCrossRefGoogle Scholar
  111. 111.
    Jones, P.L., Veenstra, G. J. C., Wade, P. A., et al. (1998) Methylated DNA and MeCP2 recruit histone deacetylase to repress transcription. Nat. Genet. 19, 187–191.PubMedCrossRefGoogle Scholar
  112. 112.
    Ng, H.H., Zhang, Y., Hendrich, B., et al. (1999) MBD2 is a transcriptional repressor belonging to the MeCP1 histone deacetylase complex. Nat. Genet. 23, 58–61.PubMedGoogle Scholar
  113. 113.
    Robertson, K.D., Ait-Si-Ali, S., Yokochi, T., et al. (2000) DNMT1 forms a complex with Rb, E2F1 and HDAC1 and represses transcription from E2F-responsive promoters. Nat. Genet. 25, 338–342.PubMedCrossRefGoogle Scholar
  114. 114.
    Taunton, J., Hassig, C.A. and Schreiber, S.L. (1996) A mammalian histone deacetylase related to the yeast transcriptional regulator Rpd3p. Science 272, 408–411.PubMedCrossRefGoogle Scholar
  115. 115.
    Verreault, A., Kaufman, P.D., Kobayashi, R., and Stillman, B. (1996) Nucleosome assembly by a complex of CAF-1 and acetylated histones H3/H4. Cell 87, 95–104.PubMedCrossRefGoogle Scholar
  116. 116.
    Ura, K., Kurumizaka, H., Dimitrov, S., et al. (1997) Histone acetylation: Influence on transcription, nucleosome mobility and positioning, and linker histone-dependent transcriptional repression. EMBO J. 16, 2096–2107.PubMedCrossRefGoogle Scholar
  117. 117.
    Pazin, M.J. and Kadonaga, J.T. (1997) What’s up and down with histone deacetylation and transcription? Cell 89, 325–328.PubMedCrossRefGoogle Scholar
  118. 118.
    Buschhausen, G., Wittig, B., Graesmann, M., and Graesmann, A. (1987) Chromatin structure is required to block transcription of the methylated herpes-simplex virus thymidine kinase gene. Proc. Natl. Acad. Sci. USA 84, 1177–1181.PubMedCrossRefGoogle Scholar
  119. 119.
    Kass, S.U., Landsberger, N., and Wolffe, A.P. (1997) DNA methylation directs a time dependent repression of transcription initiation. Curr. Biol. 7, 157–165.PubMedCrossRefGoogle Scholar
  120. 120.
    Sheridan, P.L., Sheridan, P. L., Mayall, T. P., et al. (1997) Histone acetyltransferases regulate HIV-1 enhancer activity in vitro. Genes Dev. 11, 3327–3340.PubMedGoogle Scholar
  121. 121.
    Zitnik, G., Stamatoyannopoulos, G., and Papayannopoulou, T. (1995) Effects of butyrate and glucocorticoids on gamma-globin to beta-globin gene switching in somatic-cell hybrids. Mol. Cell. Biol. 15, 790–795.PubMedGoogle Scholar
  122. 122.
    Chen, Z.J. and Pikaard, C.S. (1997) Epigenetic silencing of RNA polymerase I transcription: A role for DNA methylation and histone modification in nucleolar dominance. Genes Dev. 11, 2124–2136.PubMedGoogle Scholar
  123. 123.
    Pikaart, M.I., Recillas-Targa, F., and Felsenfeld, G. (1998) Loss of transcriptional activity of a transgene is accompanied by DNA methylation and histone deacetylation and is prevented by insulators. Genes Dev. 12, 2852–2862.PubMedGoogle Scholar
  124. 124.
    Rountree, M.R., Bachman, K.E., and Baylin, S.B. (2000) DNMT1 binds HDAC2 and a new co-repressor, DMAP1, to form a complex at replication foci. Nat. Genet. 25, 269–277.PubMedCrossRefGoogle Scholar
  125. 125.
    Habu, Y., Kakutani, T. and Paszkowski, J. (2001) Epigenetic developmental mechanisms in plants: Molecules and targets of plant epigenetic regulation. Curr. Opin. Genet. Dev. 11, 215–220.PubMedCrossRefGoogle Scholar
  126. 126.
    Jeddeloh, J.A., Stokes, T.L., and Richards, E.J. (1999) Maintenance of genomic methylation requires a SWI2/SNF2-like protein. Nat. Genet. 22, 94–97.PubMedCrossRefGoogle Scholar
  127. 127.
    Amedeo, P., Habu, Y., Afsar, K., et al. (2000) Disruption of the plant gene MOM releases transcriptional silencing of methylated genes. Nature 405, 203–206.PubMedCrossRefGoogle Scholar
  128. 128.
    Murfett, J., Wang, X.G., Hagen, G., and Guilfoyle, T.J. (2001) Identification of Arabidopsis histone deacetylase HDA6 mutants that affect transgene expression. Plant Cell 13, 1047–1061.PubMedCrossRefGoogle Scholar
  129. 129.
    Tian, L. and Chen, Z.J. (2001) Blocking histone deacetylation in Arabidopsis induces pleiotropic effects on plant gene regulation and development. Proc. Natl. Acad. Sci. USA 98, 200–205.PubMedCrossRefGoogle Scholar
  130. 130.
    Görz, A., Schafer, W., Hirasawa, E., and Kahl, G. (1988) Constitutive and light-induced Dnase I hypersensitive sites in the rbcS-genes of pea (Pisum sativum). Plant Mol. Biol. 11, 561–573.CrossRefGoogle Scholar
  131. 131.
    Jaenisch, R. (1997) DNA methylation and imprinting: Why bother? Trends Genet. 13, 323–329.PubMedCrossRefGoogle Scholar
  132. 132.
    Genger, R.K., Kovac, K.A., Dennis, E.S., et al. (1999) Multiple DNA methyltransferase genes in Arabidopsis thaliana. Plant Mol. Biol. 41, 269–278.PubMedCrossRefGoogle Scholar
  133. 133.
    Finnegan, E.J., Peacock, W.J. and Dennis, E.S. (2000) DNA methylation, a key regulator of plant development and other processes. Curr. Opin. Genet. Dev. 10, 217–223.PubMedCrossRefGoogle Scholar
  134. 134.
    Jacobsen, S.E. and Meyerowitz, E.M. (1997) Hypermethylated SUPERMAN epigenetic alleles in Arabidopsis. Science 277, 1100–1103.PubMedCrossRefGoogle Scholar
  135. 135.
    Chaudhuri, S. and Messing, J. (1994) Allele-specific parental imprinting of dzr1, a posttranscriptional regulator of zein accumulation. Proc. Natl. Acad. Sci. USA 91, 4867–4871.PubMedCrossRefGoogle Scholar
  136. 136.
    Matzke, M. and Matzke, A.J.M. (1993) Genomic imprinting in plants: parental effects and trans-inactivation phenomena. Annu. Rev. Plant Physiol. Plant Mol. Biol. 44, 53–76.CrossRefGoogle Scholar
  137. 137.
    Martienssen, R. (1998) Chromosomal imprinting in plants. Curr. Opin. Genet. Dev. 8, 240–244.PubMedCrossRefGoogle Scholar
  138. 138.
    Castle, L. A., Errampalli, D., Atherton, T. L., et al. (1993) Genetic and molecular characterization of embryonic mutants identified following seed transformation in Arabidopsis. Mol. Gen. Genet. 241, 504–514.PubMedCrossRefGoogle Scholar
  139. 139.
    Ohad, N., Margossian, L., Hsu, Y.-C., et al. (1996) A mutation that allows endosperm development without fertilization. Proc. Natl. Acad. Sci. USA 93, 5319–5324.PubMedCrossRefGoogle Scholar
  140. 140.
    Ohad, N., Yadegari, R., Margossian, L., et al. (1999) Mutations in FIE, a WD polycomb group gene, allow endosperm development without fertilization. Plant Cell 11, 407–415.PubMedCrossRefGoogle Scholar
  141. 141.
    Chaudhury, A. M., Ming, L., Miller, C., et al. (1997) Fertilization-independent seed development in Arabidopsis thaliana. Proc. Natl. Acad. Sci. USA 94, 4223–4228.PubMedCrossRefGoogle Scholar
  142. 142.
    Grossniklaus, U., Vielle-Calzada, J.-P., Hoeppner, M. A., and Gagliano, W. (1998) Maternal control of embryogenesis by MEDEA, a polycomb group gene in Arabidopsis. Science 280, 446–450.PubMedCrossRefGoogle Scholar
  143. 143.
    Kiyosue, T., Ohad, N., Yadegari, R., et al. (1999) Control of fertilization-independent endosperm development by the MEDEA polycomb gene in Arabidopsis. Proc. Natl. Acad. Sci. USA 96, 4186–4191.PubMedCrossRefGoogle Scholar
  144. 144.
    Luo, M., Bilodeau, P., Koltunow, A., et al. (1999) Genes controlling fertilization-independent seed development in Arabidopsis thaliana. Proc. Natl. Acad. Sci. USA 96, 296–301.PubMedCrossRefGoogle Scholar
  145. 145.
    Birve, A., Sengupata, A.K., Beuchle, D., et al. (2001) Su(z)12, a novel Drosophila polycomb group gene that is conserved in vertebrates and plants. Development, 128, 3371–3379.PubMedGoogle Scholar
  146. 146.
    Vinkenoog, R., Spielman, M., Adams, S., et al. (2000) Hypomethylation promotes autonomous endosperm development and rescues post-fertilisation lethality in fie-mutants. Plant Cell 12, 2271–2282.PubMedCrossRefGoogle Scholar
  147. 147.
    Sørensen, M.B., Chaudhury, A., Robert, H., et al. (2001) Polycomb group genes control pattern formation in plant seed. Curr. Biol. 11, 277–281.PubMedCrossRefGoogle Scholar
  148. 148.
    Vielle-Calzada, J.-P., Thomas, J., Spillane, C., et al. (1999) Maintenance of genomic imprinting at the Arabidopsis medea locus requires zygotic DDM1 activity. Genes Dev. 13, 2971–2982.PubMedCrossRefGoogle Scholar
  149. 149.
    Vongs, A., Kakutani, T., Martienssen, R. A., and Richards, E. J. (1993) Arabidopsis thaliana DNA methylation mutants. Science 260, 1926–1928.PubMedCrossRefGoogle Scholar
  150. 150.
    Kakutani, T., Jeddeloh, J.A., and Richards, E.J. (1995) Characterisation of an Arabidopsis thaliana DNA hypomethylation mutant. Nucl. Acids Res. 23, 130–137.PubMedCrossRefGoogle Scholar
  151. 151.
    Peterson, C.L. and Workman, J.L. (2000) Promoter targeting and chromatin remodeling by the SWI/SNF complex. Curr. Opin. Genet. Dev. 10, 187–192.PubMedCrossRefGoogle Scholar
  152. 152.
    Yadegari, R., Kinoshita, T., Lotan, O., et al. (2000) Mutations in the FIE and MEA genes that encode interacting polycomb proteins cause parent-of-origin effects on seed development by distinct mechanisms. Plant Cell 12, 2367–2381.PubMedCrossRefGoogle Scholar
  153. 153.
    Luo, M., Bilodeau, P., Dennis, E.S., et al. (2000) Expression and parent-of-origin effects for FIS2, MEA, and FIE in the endosperm and embryo of developing Arabidopsis seeds. Proc. Natl. Acad. Sci. USA 97, 10637–10642.PubMedCrossRefGoogle Scholar
  154. 154.
    Spielman, M., Vinkenoog, R., and Scott, R.J. (2001) The epigenetic basis of gender in flowering plants and mammals. Trends Genet. 17, 705–711.PubMedCrossRefGoogle Scholar
  155. 155.
    Kinoshita, T., Harada, J.J., Goldberg, R.B., and Fischer, R.L. (2001) Polycomb repression of flowering during early plant development. Proc. Natl. Acad. Sci. USA 98, 14156–14161.PubMedCrossRefGoogle Scholar
  156. 156.
    Campbell, R.B., Sinclair, D.A.R., Couling, M., and Brock, H.W. (1995) Genetic interactions and dosage effects of polycomb group genes of Drosophila. Mol. Gen. Genet. 246, 291–300.PubMedCrossRefGoogle Scholar
  157. 157.
    Shermoen, A.W. and O’Farrell, P.H. (1991) Progression of the cell cycle through mitosis leads to abortion of nascent transcripts. Cell 67, 303–310.PubMedCrossRefGoogle Scholar
  158. 158.
    Kinoshita, T., Yadegari, R., Harada, J. J., Goldberg, R. B., and Fischer, R. L. (1999) Imprinting of the MEDEA polycomb gene in the Arabidopsis endosperm. Plant Cell 11, 1945–1952.PubMedCrossRefGoogle Scholar
  159. 159.
    Russell, S.D. (1984) Ultrastructure of the sperm of Plumbago zeylanica.2. Quantitative cytology and 3-dimensional organization. Planta 162, 385–391.CrossRefGoogle Scholar
  160. 160.
    Russell, S.D. (1985) Preferential Fertilization in Plumbago— Ultrastructural evidence for gamete-level rrecognition in an angiosperm. Proc. Natl. Acad. Sci. USA 82, 6129–6132.PubMedCrossRefGoogle Scholar
  161. 161.
    Roman, H. (1948) Directed fertilization in maize. Proc. Natl. Acad. Sci. USA 34, 36–42.PubMedCrossRefGoogle Scholar
  162. 162.
    Vielle-Calzada, J-P., Baskar, R., and Grossniklaus, U. (2000) Delayed activation of the paternal genome during seed development. Nature 404, 91–94.PubMedCrossRefGoogle Scholar
  163. 163.
    Pirotta, V. (1997) PcG complexes and chromatin silencing. Curr. Opin. Genet. Dev. 7, 249–258.CrossRefGoogle Scholar
  164. 164.
    Lohuizen, M. van, Tijms, M., Voncken, J. W., Schumacher, A., Magnuson, T., and Wientjens, E. (1998) Interaction of mouse polycomb-group (Pc-G) proteins Enx1 and Enx2 with Eed: Indication for separate Pc-G complexes. Mol. Cell. Biol. 18, 3572–3579.PubMedGoogle Scholar
  165. 165.
    Sewalt, R. G. A. B., van der Vlag, J., Gunster, M. J., et al. (1998) Characterization of interactions between the mammalian polycomb-group proteins Enx1/EZH2 and EED suggests the existence of different mammalian polycombgroup protein complexes. Mol. Cell. Biol. 18, 3586–3595.PubMedGoogle Scholar
  166. 166.
    Sondek, J., Boh, A., Lambright, D.G., et al. (1996) Crystal structure of a GA protein βγ dimer at 2.1 Å resolution. Nature 379, 369–374.PubMedCrossRefGoogle Scholar
  167. 167.
    Ng, J., Li, R.H., Morgan, K., and Simon, J. (1997) Evolutionary conservation and predicted structure of the Drosophila extra sex combs repressor protein. Mol. Cell Biol. 17, 6663–6672.PubMedGoogle Scholar
  168. 168.
    Jenuwein, T., Laible, G., Dorn, R., and Reuter, G. (1998) SET domain proteins modulate chromatin domains in euand heterochromatin. Cell. Mol. Life Sci. 54, 80–93.PubMedCrossRefGoogle Scholar
  169. 169.
    Jones, C. A., Ng, J., Peterson, A. J., et al. (1998) The Drosophila esc and E(z) proteins are direct partners in Polycomb group-mediated repression. Mol. Cell. Biol. 18, 2825–2834.PubMedGoogle Scholar
  170. 170.
    Ma, H. (1997) Polycomb in plants. Trends Genet. 13, 167.PubMedCrossRefGoogle Scholar
  171. 171.
    Preuss, D. (1999) Chromatin silencing and Arabidopsis development: A role for Polycomb proteins. Plant Cell 11, 765–767.PubMedCrossRefGoogle Scholar
  172. 172.
    Spillane, C., MacDougall, C., Stock, C., et al. (2000) Interaction of the Arabidopsis polycomb group proteins FIE and MEA mediates their common phenotypes. Curr. Biol. 10, 1535–1538.PubMedCrossRefGoogle Scholar
  173. 173.
    Gutjahr, T., Frei, E., Spicer, C. et al. (1995) The Polycomb-group gene, extra sex combs, encodes a nuclear member of the WD-40 repeat family. EMBO J. 14, 4296–4306.PubMedGoogle Scholar
  174. 174.
    Choi, Y. H., Gehring, M., Johnson, L., et al. (2002) DEMETER, a DNA glycosylase domain protein, is required for endosperm gene imprinting and seed viability in Arabidopsis. Cell 110, 33–42.PubMedCrossRefGoogle Scholar
  175. 175.
    Dickinson, H. and Scott, R.J. (2002) DEMETER, goddess of the harvest, activates maternal MEDEA to produce the perfect seed. Mol. Cell 10, 5–7.PubMedCrossRefGoogle Scholar
  176. 176.
    Lohe, A. and Chaudhury, A. (2002) Demeter: on seeds and goddesses. Plant Cell, 14, 2981–2983.PubMedCrossRefGoogle Scholar
  177. 177.
    Cassar, G., Mohammed, M., John, T.M., et al. (1998) Differentiating between parthenogenetic and positive development embryos in turkeys by molecular sexing. Poultry Science 77, 1463–1468.PubMedGoogle Scholar
  178. 178.
    Moritz, C., McCallum, H., Donnellan, S., and Roberts, J.D. (1991) Parasite loads in parthenogenetic and sexual lizards (Heteronotia binoei): support for the Red Queen hypothesis. Proc. R. Soc. Lond. [B] 244, 145–149.CrossRefGoogle Scholar
  179. 179.
    MacGulloch, R.D., Murphy, R.W., Kupriyanova, L.A., and Darevski, I.S. (1997) The Caucasian rock lizard Lacerta rostombekovi: A monoclonalparthenogenetic vertebrate. Biochem. Syst. Ecol. 25, 33–37.CrossRefGoogle Scholar
  180. 180.
    Price, A.H. (1992) Comparative behavior in lizards of the genus Cnemidophorus (Teiidae) with comments on the evolution of parthenogenesis in reptiles. Copeia 2, 323–331.CrossRefGoogle Scholar
  181. 181.
    Krotoski, D.M., Reinschmidt, D.C., and Tompkins, R. (1985) Developmental mutants isolated from wild-caught Xenopus laevis by gynogenesis and inbreeding. J. Exp. Zool. 233, 443–449.PubMedCrossRefGoogle Scholar
  182. 182.
    Yu, H.J., Shi, C.P. and Liang, J.H. (1986) Production of tetraploid and androgenetic diploid adults of Xenopus laevis by suppression of first cleavage. Kexue Tongbao 31, 720–720.Google Scholar
  183. 183.
    Tompkins, R. and Reinschmidt, D. (1991) Experimentally induced homozygosity in Xenopus laevis. Methods Cell Biol. 36, 35–44.PubMedCrossRefGoogle Scholar
  184. 184.
    Hubbs, C.L. and Hubbs, L.C. (1932) Apparent pathenogenesis in nature, in a form of fish of hybrid origin. Science 76, 628–630.CrossRefPubMedGoogle Scholar
  185. 185.
    Vrijenhoek, R. (1994) Unisexual fish: model systems for studying ecology and evolution. Annu. Rev. Ecol. Syst. 25, 71–96.CrossRefGoogle Scholar
  186. 186.
    Streisinger, G., Walker, C., Dower, N., Knauber, D., and Singer, F. (1981) Production of clones of homozygous diploid zebra fish (Brachyodanio rerio) Nature 291, 293–296.PubMedCrossRefGoogle Scholar
  187. 187.
    May, B., Henley, K.J., Krueger, C.C. and Gloss, S.P. (1988) Androgenesis as a mechanism for chromosome set manipulation in brook trout (Salvelinus fontinalis). Aquaculture 75, 57–70.CrossRefGoogle Scholar
  188. 188.
    Ihssen, P.E., McKay, L.R., McMillan, I., and Phillips, R.B. (1990). Ploidy manipulation and gynogenesis in fishes: cytogenetic and fisheries applications. Trans. Am. Fish. Soc. 119, 698–717.CrossRefGoogle Scholar
  189. 189.
    Corley-Smith, G.E., Lin, C.J. and Brandhorst, B.P. (1996) Production of androgenetic zebrafish (Danio rerio). Genetics 142, 1265–1276.PubMedGoogle Scholar
  190. 190.
    Hörstgen-Schwark, G. (1993) Production of homozygous diploid zebra fish (Brachydanio rerio). Aquaculture 112, 25–37.CrossRefGoogle Scholar
  191. 191.
    Martin, C.C. and McGowan, R. (1995) Parent-of-origin specific effects on the methylation and expression of a transgene in the zebrafish, Danio rero. Genet. Res. Camb. 65, 21–28.Google Scholar
  192. 192.
    Drosopoulos, S. (1976) Triploid pseudogamous biotype of the leaf-hopper Muellerianella fairmairei. Nature 263, 499–500.PubMedCrossRefGoogle Scholar
  193. 193.
    Drosopoulos, S. (1978) Laboratory synthesis of a pseudogamous triploid species of the genus Muellerianella (Homoptera, Delphacidae). Evolution 32, 916–920.CrossRefGoogle Scholar
  194. 194.
    Normark, B.B. (2000) Molecular systematics and evolution of the aphid family Lachnidae. Mol. Phylogen. Evol. 14, 131–140.CrossRefGoogle Scholar
  195. 195.
    Gautam, D.C., Crema, R., and Pagliai, A.M.B. (1993) Cytogenetic mechanisms in Aphids. Boll. Zool. 60, 233–244.Google Scholar
  196. 196.
    Tinti, F. and Scali, V. (1993) Chromosomal evidence of hemiclonal and all-paternal offspring production in Bacillus rossius grandii benazzii (Insecta, Phasmatodea). Chromosoma 102, 403–414.CrossRefGoogle Scholar
  197. 197.
    Tinti, F. and Scali, V. (1995) Allozymic and cytological evidence for hemiclonal, all paternal, and mosaic off-spring of the hybridogenetic stick insect Bacillus rossius grandii grandii. J. Exp. Zool. 273, 149–159.CrossRefGoogle Scholar
  198. 198.
    Komma, D.J. and Endow, S.A. (1995) Haploidy and androgenesis in Drosophila. Proc. Natl. Acad. Sci. USA 92, 11,884–11,888.CrossRefGoogle Scholar
  199. 199.
    Presgraves, D.C. (2000) A genetic test of the mechanism of Wolbachia-induced cytoplasmic incompatibility in Drosophila. Genetics 154, 771–776.PubMedGoogle Scholar
  200. 200.
    Cook, J.M. (1993) Sex determination in the Hymenoptera: A review of models and evidence. Heredity 71, 421–435.Google Scholar
  201. 201.
    Beukeboom, L.W. (1995) Sex determination in Hymenoptera: A need for genetic and molecular studies. BioEssays 17, 813–817.PubMedCrossRefGoogle Scholar
  202. 202.
    Huigens, M.E., Luck, R.F., Klaassen, R.H.G., et al. (2000) Infectious parthenogenesis. Nature 405, 178–179.PubMedCrossRefGoogle Scholar
  203. 203.
    Crouse, H.V. (1960) The controlling element in sex chromosome behaviour in Sciara. Genetics 45, 1425–1443.Google Scholar
  204. 204.
    Crouse, H.V. (1966) An inducible change in state on the chromosome inheritance and the problem of “imprinting” in Sciara. (Sciaridae, Diptera). Chromosoma 18, 230–253.CrossRefGoogle Scholar
  205. 205.
    Birger, Y., Shemer, R., Perk, J., and Razin, A. (1999) The imprinting box of the mouse Igf2r gene. Nature 397, 84–88.PubMedCrossRefGoogle Scholar
  206. 206.
    Stephens, S.G. (1942) Colchicine-produced polyploids in Gossypium: An autotetraploid Asiatic cotton and certain of its hybrids with diploid species. J. Genet. 44, 272–295.CrossRefGoogle Scholar
  207. 207.
    von Wangenheim, K.-H. (1957) Untersuchungen über den Zusammenhang zwischen Chromosomenzahl und Kreuzbarkeit bei Solanum -Arten. Zeitschr. Indukt. Abstam. Vererbungslehre 88, 21–37.CrossRefGoogle Scholar
  208. 208.
    Howard, H.W. (1947) Seed size in crosses between diploid and autotetraploid Nasturtium officinale and allotetraploid N. uniseriatum. J. Genet. 48, 111–118.PubMedGoogle Scholar
  209. 209.
    Johnston, S.A., den Nijs, T.P.M., Peloquin, S.J., and Hanneman, R.E. (1980) The significance of genic balance to endosperm development in interspecific crosses. Theor. Appl. Genet. 57, 5–9.Google Scholar
  210. 210.
    Ortiz, R. and Ehlenfeldt, M.K. (1992) The importance of endosperm balance number in potato breeding and the evolution of tuber-bearing Solanum species. Euphytica 60, 105–113.Google Scholar
  211. 211.
    Johnston, S.A. and Hanneman, R.E. (1982) Manipulations of endosperm balance number overcome crossing barriers between diploid Solanum species. Science 217, 446–448.CrossRefPubMedGoogle Scholar
  212. 212.
    Quarin, C.L. (1999) Effect of pollen source and pollen ploidy on endosperm formation and seed set in pseudogamous apomictic Paspalum notatum. Sex. Plant Reprod. 11, 331–335.CrossRefGoogle Scholar
  213. 213.
    Carputo, D., Monti, L., Werner, J.E., and Frusciante, L. (1999) Uses and usefulness of endosperm balance number. Theor. Appl. Genet. 98, 478–484.CrossRefGoogle Scholar
  214. 214.
    Bushell, C., Spielman, M., and Scott, R.J. (in prep.) The basis of natural and artificial post-zygotic hybridisation barriers in Brassica species. Plant Cell, in press.Google Scholar
  215. 215.
    Chen, Z.J., Comai, L., and Pikaard, C.S. (1998) Gene dosage and stochastic effects determine the severity and direction of uniparental ribosomal RNA gene silencing (nucleolar dominance) in Arabidopsis allopolyploids. Proc. Natl. Acad. Sci. USA 95, 14,891–14,896.Google Scholar
  216. 216.
    Kamm, A., Galasso, I., Schmidt, T., and Heslop-Harrison, J. S. (1995) Analysis of a repetitive DNA family from Arabidopsis-arenosa and relationships between Arabidopsis species. Plant Mol. Biol. 27, 853–862.PubMedCrossRefGoogle Scholar
  217. 217.
    Okane, S.L., Schaal, B.A., and AlShenbaz, I.A. (1996) The origins of Arabidopsis suecica (Brassicaceae) as indicated by nuclear rDNA sequences. Sys. Bot. 21, 559–566.CrossRefGoogle Scholar
  218. 218.
    van Dijk, P. and van Damme, J. (2000) Apomixis technology and the paradox of sex. Trends Plant Sci. 5, 81–84.PubMedCrossRefGoogle Scholar
  219. 219.
    Grossniklaus, U., Nogler, G.A., and van Dijk, P.J. (2001) How to avoid sex: The genetic control of gametophytic apomixis. Plant Cell 13, 1491–1497.PubMedCrossRefGoogle Scholar
  220. 220.
    Vinkenoog, R. and Scott, R.J. (2001) Autonomous endosperm development in flowering plants: How to overcome the imprinting problem? Sex. Plant Rep. 14, 189–194.CrossRefGoogle Scholar
  221. 221.
    Spielman, M., Vinkenoog, R., and Scott, R.J.(2003) Genetic mechanisms of Apomixis. Trans. R. Soc. London, in press.Google Scholar
  222. 222.
    Cooper, D.C. and Brink, R.A. (1949) The endosperm-embryo relationship in an autonomous apomict, Taraxacum officinale. Bot. Gaz. 111, 139–153.CrossRefGoogle Scholar
  223. 223.
    Tas, I.C.Q. and van Dijk, P.J. (1999) Crosses between sexual and apomictic dandelions (Taraxacum). I. The inheritance of apomixis. Heredity 83, 707–714.PubMedCrossRefGoogle Scholar
  224. 224.
    van Dijk, P.J., Tas, I.C.Q., Falque, M., and Bakx-Schotman, T. (1999) Crosses between sexual and apomictic dandelions (Taraxacum). II. The breakdown of apomixis. Heredity 83, 715–721.PubMedCrossRefGoogle Scholar
  225. 225.
    Danilevskaya, O.N., Hermon, P., Hantke, S., et al. (2003) Duplicated fie genes in maize: Expression pattern and imprinting suggest distinct functions. Plant Cell, in press. Google Scholar
  226. 226.
    Bestor, T.H. (2000) The DNA methyltransferases of mammals. Hum. Mol. Genet. 9, 2395–2402.PubMedCrossRefGoogle Scholar

Copyright information

© Humana Press Inc. 2003

Authors and Affiliations

  • Rinke Vinkenoog
    • 1
  • Catherine Bushell
    • 1
  • Melissa Spielman
    • 1
  • Sally Adams
    • 1
    • 2
  • Hugh G. Dickinson
    • 3
  • Rod J. Scott
    • 1
  1. 1.Department of Biology and BiochemistryUniversity of BathBathUK
  2. 2.Friedrich Miescher InstitutBaselSwitzerland
  3. 3.Department of Plant SciencesUniversity of OxfordOxfordUK

Personalised recommendations