细胞遗传学课件

• Song KM, Lu P, Tang K, Osborn TC. Rapid genome change in synthetic polyploids of Brassica and its implications for polyploids evolution. Proc Natl Acad Sci USA, 1995, 92:7719-7723
Typical polyploid crops, wheat, oat, coffee, potato, canola, soybean, sugarcane, tobacco, cotton
Abundance of allopolyploid plants
• Because most ancient polyploids have undergone an evolutionary process of chromosomal and perhaps genic “diploidization”, their polyploid history may be obscured at the cytological and classic genetics levels. Polyploid nature of many plant genomes was not evident until the advent of comparative genomics and wholegenome sequencing-maize, Arabidopsis — traditionally diploids.
Abundance of allopolyploid plants
• Given these and other recent examples from plants, it is probably safe to state that there are no bona fide diploid species in the plant kingdom.
2 Introduction－ Abundance of allopolyploid plants
• Polyploidy, resulting from either duplication of a single but complete genome (autopolyploidy) or from combination of two or more differentiated genomes (allopolyploidy), is a prominent mode of speciation in plants. It is difficult to overstate the importance of polyploidy in the evolutionary history of plants.
• Yang SS, Cheung F, Lee JJ, Ha M, Wei NE, et al. Accumulation of genome-specific transcripts, transcription factors and phytohormonal regulators during early stages of fiber cell development in allotetraploid cotton. Plant J, 2006, 47:761–75
• Liu B, Wendel JF. Non-Mendelian phenomena in allopolyploid genome evolution. Curr Genomics, 2002, 3: 489-506
• Liu B, Wendel JF. Epigenetic phenomena and the evolution of plant allopolyploids. Mol Phylogenet Evol, 2003, 29: 365-379
• Stupar RM, Bhaskar PB, Yandell BS, et al. Phenotypic and transcriptomic changes associated with potato autopolyploidization. Genetics, 2007, 176: 2055-2067
植物多倍体的遗传及表观遗传
Genetic and epigenetic changes in plant polyploids
1 主要参考文献
Adams KL, Cronn R, Percifield R, Wendel JF. Genes duplicated by polyploidy show unequal contribution to the transcriptome and organspecific reciprocal silencing. Proc Natl Acad Sci USA, 2003, 100: 4649~4654
(b) Epigenetic silencing in resynthesized allopolyploids. A. suecica (As, white flower), natural allotetraploid. A. thaliana (not shown) and A. arenosa (Aa), have white and pink flowers. The flower colors in 3rd generation (S3–1, 2, and 3) segregate from all white (S3– 1) to all pink (S3–3). Variegated flower colors (S3–2).
• Comai L. The advantages and disadvantages of being polyploidy. Nat Rev Genet, 2005, 6: 836-846
• Leitch AR, Leitch IJ. Genomic plasticity and the diversity of polyploidy plants. Sci, 2008, 320: 481-483
• Otto SP, Whitton J. Polyploidy incidence and evolution. Ann Rev Genet, 2000, 34: 401-437
• Soltis PS, Soltis DE. The role of genetics and genomic attributes in the success of polyploids. Proc Natl Acad Sci USA, 2000, 97:7051-707
• 人类在合成多倍体方面收效甚微！
Abundance of allopolyploid plants
• While estimates vary regarding the proportion of angiosperms that have experienced one or more episodes of chromosome doubling at some point in their evolutionary history, it is at least 50% and may be higher than 70%; perhaps 95% of pteridophytes have experienced at least one episode of polyploidizLeabharlann tion in their past.
• Wang JL, Tian L, Lee HS, Wei NE, Jiang HM, et al. Genomewide nonadditive gene regulation in Arabidopsis allotetraploids. Genetics, 2006, 172:507-517
• Novel intergenomic interactions as a consequence of the merger of two formerly isolated genomes;
Non-Mendelian Phenomena in Allopolyploid Genome Evolution
3 Non-Mendelian Phenomena in
Allopolyploid Genome Evolution
• non-Mendelian attributes: those not characterized by conventional transmission genetics.
• Mysterious process of rapid and in some cases directed structural changes that occur in polyploid genomes upon their formation;
• Epigenetic mechanisms in nascent allopolyploidy, such as nucleolar dominance, gene silencing and mobile element activation.
Chen ZJ. Genetic and epigenetic mechanisms for gene expression and phenotypic variation in plant polyploids. Ann Rev Plant Biol, 2007, 58: 377-406
• Comai L. Genetic and epigenetic interactions in allopolyploid plants. Plant Mol Biol, 2000, 43:387~399
Adams KL. Evolution of duplicate gene expression in polyploidy and hybrid plants. J Hered, 2007, 98: 136-141