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

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Chapter 5In order to investigate the structure of these Bs in more detail, FISH was applied using 5SrDNA and 45S rDNA as probes (Fig. 5.2a). In addition, the telomeric repeat sequence wasused as a probe to detect the status of the chromosome ends. A notable feature was that FISHclearly detected several hybridization sites of both 5S rDNA (green) and 45S rDNA (red) sitesin the standard chromosomes (Fig. 5.2a). The B chromosomes clearly contained two equalarms and possessed blocks of 5S rDNA on both arms (inset in Fig. 5.2a) flanked by telomericsequences (result not shown). In view of the identical morphology of both arms of these Bchromosomes it was concluded that they are isochromosomes.Small aberrant chromosomes in progeny of LA × AA crossOut of 25 triploid progenies derived from LA × AA cross, 22 genotypes were euploids withthe expected 36 chromosomes. None of these normal triploids possessed any extrachromosomes or fragments, similar to both of the parents from which the progeny wasderived (results not shown). In the other three genotypes of this progeny, viz., 074051-9,084798-2 and 084798-6, however, all the somatic cells possess 35 chromosomes togetherwith a small chromosome in all the somatic cells. Because the small chromosome occurred inall three genotypes together with 35, instead of 36 normal chromosomes, the small structureswhich are probably related to the missing A chromosomes in each genotype are called‘aberrant’. The size of the aberrant chromosomes varied from 4.9 to 8.4 μm in differentgenotypes (Table 5.2). The structural organization of these three small chromosomes wasinvestigated through GISH and FISH using 5S rDNA, 45S rDNA and telomeric sequences asprobes. The results of GISH and FISH analyses of the aberrant chromosome in genotype074051-9, are shown in Fig. 5.2b, c and d. GISH results indicated that the small aberrantchromosome in genotype 074051-9 (Fig. 5.2b) and 084798-2 originated from Longiflorumwhereas the aberrant chromosome in 084798-6 was derived from Asiatic genome. By usingtwo probes, 45S rDNA and 5S rDNA, different hybridization sites were detected throughFISH in the complement (Fig. 5.2c). The striking feature, however, was that the smallaberrant chromosome in genotype 074051-9 possessed a hybridization site of 45S rDNArepeat (red fluorescence) on each of its two arms in proximal positions (arrow and inset in Fig.5.2c). When probed with telomeric sequences, FISH clearly demonstrated the presence oftelomeres in the small aberrant chromosome (Fig. 5.2d, arrow and inset). Thus, each arm ofthis aberrant chromosome has a block of 45S rDNA proximally followed by a non-hybridizedregion and a telomere. In two other genotypes, 084798-2 and 08798-6, the small aberrantchromosomes were clearly median chromosomes without any rDNA repeats but possessednormal telomeres as revealed by FISH (results not shown). In view of the similar morphologyof the arms of small chromosomes in all three genotypes, they were concluded to beisochromosomes as well.66
Small aberrant chromosomes and B chromosomes in Lilium hybridsTable 5.2. Comparison of arm length between the aberrant small chromosome and the missingchromosome in three LAA genotypesArm length ofShort arm lengthMissingGenotype aberrant chr.of missing chr. Other similaritychromosomes(µm)(µm)**074051-9 4.21±0.17 L4 4.33 45s rDNA084798-2 2.45±0.08 L9 2.36084798-6 3.38±0.06 A6 3.73Note: L4 and L9 stands for chromosome 4 and 9 from Longiflorum genome respectively. Similarly,A6 represents chromosome 6 from Asiatic genome. ** data from Khan et al. (2009a)Fig. 5.3. A comparison of the small aberrant chromosome and the missing chromosome (L4) ingenotype 074051-9.67
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A molecular cytogenetic analysis of
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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
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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 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 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
Page 97 and 98: ReferencesLarson, S.R., Kishii, M.,
Page 99 and 100: ReferencesMcClintock, B. 1931. Cyto
Page 101 and 102: ReferencesRai, R., Zheng, H., He, H
Page 103 and 104: ReferencesStewart, R.N. 1947. The m
Page 105: 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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