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

More documents

Recommendations

Info

Chapter 3Fig. 3.2. Homoeologous chromosome segregation and crossing over ar anaphase I during meiosis ofinterspecific hybrids of lily. (a) Anaphase I segregation of homoeologous chromosomes confirmed theoccurrence of single crossover, three strand double and four strand double crossovers. (b) Anaphase Isegregation of homoeologous chromosomes illustrated the happening of two strand double and fourstrand double crossovers. (c) Anaphase I segregation of pollen mother cells indicated the happening ofsingle crossover and a two strand double crossover; (d) Anaphase I segregation of pollen mother cellsin meiosis revealed the occurrence of single, three strand double, four strand double and multiplecrossovers40
Intergenomic recombination and chromosome translocation in Lilium hybridsthe detection of not only reductional and equational segregation of chromosomes in somecases but also identify different types of cross-overs between the non-sister chromatids ofhomoeologous chromosome pairs. Assuming normal chromosome pairing and crossing-overin LA hybrids, one can expect different types cross-overs to occur, viz., two strand single, twostrand double, three strand double, four strand double and multiple cross-overs (Fig. 3.3). Allthe expected types have been found in the present study (Fig. 3.2a, b, c and d). Then thequestion arises whether these exchanges of segments between the non-sister chromatids ofeach pair of homoeologous chromosomes should be considered as recombinations ortranslocations? Undoubtedly the latter possibility must be ruled out because cross-over eventsare locus specific events between homoeologous pairs of chromosomes. Moreover thefrequencies of exchanges per cell are so high that it is inconceivable that such high rates ofchromosome mutations (translocations) can occur spontaneously in any organism.Based on difficulty of crossing, F1 hybrid sterility, reduced chromosome pairing andclearly differential fluorescence of chromosomes, the genomes of L. longiflorum and Asiaticspecies are well differentiated. Despite this, however, there is almost completely normalcrossing-over between some of the pairs of homoeologous chromosomes. Considering thecrossover types observed in this study as well as those reported earlier (Zhou et al. 2008a), thegenomes of different groups of Lilium species appear to be homo-sequential. So much so, thatit has enabled the construction of cytological maps of three different genomes, viz.,Longiflorum, Asiatic and Oriental groups (Khan et al. 2009a). In view of the high degree ofhomoeology between the genomes, the exchanges of chromosome segments through crossingoverevents cannot be considered as translocations.The occurrence of either duplication or translocation in the cultivar ‘Connecticut King’ isof considerable importance because attempts have been made to construct molecular maps inrecent years (Abe et al. 2002; Khan 2009; Shahin et al. 2011; Van Heusden et al. 2002). Amain problem to establish molecular maps is that the number of linkage groups exceed thebasic chromosome number. One cause of this problem is the presence of very large genomesin Lilium species with a large basic chromosome number (x=12), which means larger numberof markers and mapping individuals are needed. On the other hand, chromosomerearrangements provide another candidate reason for the mapping problem of lily. Althoughthe relationship between chromosome structure variation and genetic mapping has not beenwell studied, limited reports have showed that reciprocal translocation can also cause thevariation of linkage groups (Farré et al. 2010; Kamphuis et al. 2007; Larson et al. 2011). Untilnow, none of the chromosomes of Lilium species have been associated with any of the genesor molecular markers so far. In this context, it might be essential to carefully analyse thegenome of ‘Connecticut King’ and identify the aberration that has been encountered.41
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 45: 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
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
show all

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

Create successful ePaper yourself

Delete template?

Save as template?