A molecular cytogenetic analysis of chromosome behavior in Lilium ...

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Chapter 3with Vectashield. Finally, photographs were taken with a Canon digital camera attached to aZeiss Axiophot fluorescence microscope.Fig. 3.1. Chromosome pairing at metaphase I during meiosis of interspecific hybrids of lily. (a) Apollen mother cell with 12 bivalents involving homoeologous pairing (006001-6); (b) Formation of aquadrivalent containing two Asiatic and two Longiflorum chromosomes (white arrow) in one of thepollen mother cells of genotype 006001-6; (c) Formation of a trivalent including two chromosomesfrom Asiatic and one chromosome from Longiflorum (white arrow) in pollen mother cells of genotype006001-6; (d) Formation of a bivalent resulted from non-homologous chromosomes from Asiaticgenome (white arrow) in genotype 006001-13. Green fluorescence stands for chromosomes fromAsiatic genome and blue fluorescence stands for chromosomes from Longiflorum genome.ResultsChromosome pairing at metaphase I in LA hybridsSince the two parents, L. longiflorum and Asiatic lilies, belong to two different botanicalsections, homoeologous chromosomes were clearly distinguished in the hybrids by GISH (Fig.3.1a, b, c and d). In order to estimate the extent of chromosome pairing, metaphase I stageswere analysed in 13 different genotypes (Table 3.1). In each case approximately 120 to 250pollen mother cells were analysed. There was a great variation regarding the chromosomeassociations in different genotypes. The average number of bivalents per cell ranged from 3.936
Intergenomic recombination and chromosome translocation in Lilium hybrids(006001-80) to 11.2 (006001-6) in these different hybrids. Also, the number of bivalentsamong different pollen mother cells within a genotype varied considerably: in genotype006001-6 with high average, for example, the number of bivalents varied between 9 to 12 percell (for 12 bivalents, see Fig. 3.1a), whereas in another genotype with a low average ofbivalents (e.g., 006001-36) they varied between 2 to 9 per cell. With rare exceptions, bivalentsinvariably resulted from the association of homoeologous chromosomes of the parents thatcould be clearly identified based on differential fluorescence labelling.Besides bivalents and univalents, there were also multivalents as well as bivalents resultingfrom non-homologous association in some of the cells of two genotypes (006001-6 and006001-13, arrows in Fig. 3.1b, c and d). The common feature of the quadrivalents (Fig. 3.1b),the trivalents (Fig. 3.1c) and the non-homologous bivalents (Fig. 3.1d) was the association oftwo chromosomes from the Asiatic genome (blue fluorescence). Such non-homologousassociation between two chromosomes within a haploid set from a parent was normally notexpected to occur. In the multivalents of genotype 006001-6, two chromosomes from Asiaticgenome as well as at least one chromosome of Longiflorum genome was involved (greenfluorescence in Fig. 3.1b and c). The formation of multivalents and nonhomologous bivalentsin the F1 hybrid progenies might be due to the presence of a duplication that is common totwo non-homologous chromosomes within the Asiatic parent ‘Connecticut King’.Alternatively, a reciprocal translocation might be present in the Asiatic parent and aduplication-deficiency gamete (a gametes with duplications as well as deletions) transmittedto the progeny that formed multivalent (see Fig. 3.3). A notable feature of multivalents wasthe absence of ring multivalents. This was explained from the fact that most of thechromosomes in the karyotypes of Lilium species consist of sub-metacentric or sub-telocentricchromosomes they do not form typical ring quadrivalents. Of particular interest was theassociation of two Longiflorum chromosomes at both ends in the chain quadrivalent (Fig.3.1b, arrow). The probable explanation for this type of quadrivalent formation is shown in Fig.3.3 in which both homo- (solid line in Fig. 3.3) and homoeologous (dashed lines in Fig. 3.3)chromosome associations are highlighted. Based on different possibilities of chiasmaformation between the four chromosomes that are involved in multivalent formation, differentmeiotic configurations shown in Fig. 3.1 can be explained as follows: a) If chiasmata areformed in the homoeologous regions but not in the homologous region they result in forming12 bivalents (Fig. 3.1a). b) If chiasmata are formed in both the homoeologous regions as wellas the homologous region it leads to the formation of a quadrivalent in which two Asiaticchromosomes are adjacent each other (Fig 3.1b). c) If a chiasma is formed in the homologousregion followed by a chiasma in one of the homoeologous regions, then it results in a trivalentwith two Asiatic chromosomes (adjacent to each other) and a Longiflorum chromosome (Fig.3.1c). d) When there is a chiasma formation only in the homologous region but not in thehomoeologous regions, this results in the association of two non-homologous Asiaticchromosomes (Fig. 3.1d). Except for the two genotypes that formed a multivalent and37
Page 3 and 4: A molecular cytogenetic analysis of
Page 5: Table of ContentsChapter 1General I
Page 8 and 9: Chapter 1LilyLilies belong to genus
Page 10 and 11: Chapter 1counterparts (Finnegan 200
Page 12 and 13: Chapter 1renewed interest in detect
Page 14 and 15: Chapter 1recombination, mechanisms
Page 16 and 17: Chapter 1is only an equational segr
Page 18 and 19: Chapter 1quite divergent with vario
Page 21 and 22: Chapter 2An assessment of chromosom
Page 23 and 24: Chromosome rearrangements in Lilium
Page 37 and 38: Chapter 3Elucidation of intergenomi
Page 39 and 40: Intergenomic recombination and chro
Page 41: Intergenomic recombination and chro
Page 49: Intergenomic recombination and chro
Page 52 and 53: Chapter 4AbstractMeiotic abnormalit
Page 54 and 55: Chapter 4There are some criteria to
Page 56 and 57: Chapter 4FISH experiments were perf
Page 58 and 59: Chapter 4was apparently shorter, wi
Page 60 and 61: Chapter 4bridges is explained as U-
Page 62 and 63: Chapter 4of the sexual polyploidize
Page 64 and 65: Chapter 4fragment have the same len
Page 66 and 67: Chapter 5AbstractSupernumerary (B)
Page 68 and 69: Chapter 5their origin, the structur
Page 70 and 71: Chapter 5Fig. 5.1. Discovery of B c
Page 72 and 73: Chapter 5In order to investigate th
Page 74 and 75: Chapter 5Centric breakage and fusio
Page 76 and 77: Chapter 5It has not, however, been
Page 78 and 79: Chapter 6The results presented in t
Page 80 and 81: Chapter 6model for molecular cytoge
Page 82 and 83: Chapter 6Fig. 6.2. The meiosis proc
Page 84 and 85: Chapter 6over events during FDR mei
Page 86 and 87: Chapter 6been detected with GISH an
Page 88 and 89: Chapter 6Another feature caused by
Page 91 and 92: ReferencesAbe, H.A., Nakano, M.N.,
Page 93 and 94:
ReferencesChen, Q., and Armstrong,
Page 95 and 96:
ReferencesHartlerode, A.J., and Scu
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ReferencesLarson, S.R., Kishii, M.,
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ReferencesMcClintock, B. 1931. Cyto
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ReferencesRai, R., Zheng, H., He, H
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ReferencesStewart, R.N. 1947. The m
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ReferencesZhang, L., Pickering, R.,
Page 108 and 109:
Summarychromosome rearrangements. T
Page 111 and 112:
SamenvattingLelie (Lilium) is in de
Page 113 and 114:
Samenvattingaantal 35 met daarnaast
Page 115 and 116:
摘要百合系百合科百
Page 117 and 118:
Acknowledgements淡看世事去
Page 119:
Curriculum VitaeSonglin Xie was bor
Page 123:
Education Statement of the Graduate
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