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Triangle of U

January 01, 1970

The triangle of U (/uː/ OO) is a theory about the evolution and relationships among the six most commonly known members of the plant genus Brassica. The theory states that the genomes of three ancestral diploid species of Brassica combined to create three common tetraploid vegetables and oilseed crop species.[1] It has since been confirmed by studies of DNA and proteins.[2]

The "triangle of U" diagram, showing the genetic relationships among six species of the genus Brassica. Chromosomes from each of the genomes A, B and C are represented by different colours.

The theory is summarized by a triangular diagram that shows the three ancestral genomes, denoted by AA, BB, and CC, at the corners of the triangle, and the three derived ones, denoted by AABB, AACC, and BBCC, along its sides.

The theory was first published in 1935 by Woo Jang-choon,[3] a Korean-Japanese botanist (writing under the Japanized name "U Nagaharu").[4] Woo made synthetic hybrids between the diploid and tetraploid species and examined how the chromosomes paired in the resulting triploids.

Woo's theory edit

The six species are

Genomes Chr. count Species Description
Diploid
AA 2n=2x=20 Brassica rapa (syn. B. campestris) turnip, napa cabbage, bok choi
BB 2n=2x=16 Brassica nigra black mustard
CC 2n=2x=18 Brassica oleracea cabbage, kale, broccoli, Brussels sprouts, cauliflower, kohlrabi
Tetraploid
AABB 2n=4x=36 Brassica juncea Brown mustard
AACC 2n=4x=38 Brassica napus rapeseed, rutabaga
BBCC 2n=4x=34 Brassica carinata Ethiopian mustard

The code in the "Chr.count" column specifies the total number of chromosomes in each somatic cell, and how it relates to the number n of chromosomes in each full genome set (which is also the number found in the pollen or ovule), and the number x of chromosomes in each component genome. For example, each somatic cell of the tetraploid species Brassica napus, with letter tags AACC and count "2n=4x=38", contains two copies of the A genome, each with 10 chromosomes, and two copies of the C genome, each with 9 chromosomes, which is 38 chromosomes in total. That is two full genome sets (one A and one C), hence "2n=38" which means "n=19" (the number of chromosomes in each gamete). It is also four component genomes (two A and two C), hence "4x=38".[2]

The three diploid species exist in nature, but can easily interbreed because they are closely related. This interspecific breeding allowed for the creation of three new species of tetraploid Brassica.[3] (Critics, however, consider the geological separation too large.) These are said to be allotetraploid (containing four genomes from two or more different species); more specifically, amphidiploid (with two genomes each from two diploid species).[2]

Further relationships edit

The framework proposed by Woo, although backed by modern studies, leaves open questions about the time and place of hybridization and which species is the maternal or paternal parent. B. napus (AACC) is dated to have originated about 8,000[5] or 38,000–51,000[6] years ago. The homologous part of its constituent chromosomes has crossed over in many cultivars.[5] B. juncea (AABB) is estimated to have originated 39,000–55,000 years ago.[6] As of 2020, research on organellar genomes shows that B. nigra (BB) is likely the "mother" of B. carinata (BBCC) and that B. rapa (AA) likely mothered B. juncea. The situation with B. napus (AACC) is more complex: some specimens have a rapa-like organellar genome, while the rest indicate an ancient, unidentified maternal plant.[2]

Data from molecular studies indicate the three diploid species are themselves paleohexaploids.[7][8]

Allohexaploid species edit

In 2011 and 2018, novel allohexaploids (AABBCC) located at the "center" of the triangle of U were created by different means,[9][10][11] for example by crossing B. rapa (AA) with B. carinata (BBCC), or B. nigra (BB) with B. napus (AACC), or B. oleracea (CC) with B. juncea (AABB), followed by chromosome duplication of the triploid (ABC) offspring to generate doubled haploid (AABBCC) offspring.[11]

In addition, two stable allohexaploid (AABBSS) intergeneric hybrids between Indian mustard (B. juncea, AABB) and white mustard (Sinapis alba, SS) were created in 2020 by protoplast fusion.[12]

See also edit

References edit

  1. ^ Jules, Janick (2009). Plant Breeding Reviews. Vol. 31. Wiley. p. 56. ISBN 978-0-470-38762-7.
  2. ^ a b c d Xue, JY; Wang, Y; Chen, M; Dong, S; Shao, ZQ; Liu, Y (2020). "Maternal Inheritance of U's Triangle and Evolutionary Process of Brassica Mitochondrial Genomes". Frontiers in Plant Science. 11: 805. doi:10.3389/fpls.2020.00805. PMC 7303332. PMID 32595682. Comparative genomic analyses can assign the subgenomes of the allotetraploids, B. juncea and B. napus, with their diploid parental taxa, and the results were in agreement with U's triangle (Chalhoub et al., 2014; Yang et al., 2016a). [...]
  3. ^ a b Nagaharu U (1935). "Genome analysis in Brassica with special reference to the experimental formation of B. napus and peculiar mode of fertilization". Japan. J. Bot. 7: 389–452.
  4. ^ (in Korean). Archived from the original on 2007-09-27.
  5. ^ a b Chalhoub, B; Denoeud, F; Liu, S; Parkin, IA; Tang, H; Wang, X; Chiquet, J; Belcram, H; Tong, C; Samans, B; Corréa, M; Da Silva, C; Just, J; Falentin, C; Koh, CS; Le Clainche, I; Bernard, M; Bento, P; Noel, B; Labadie, K; Alberti, A; Charles, M; Arnaud, D; Guo, H; Daviaud, C; Alamery, S; Jabbari, K; Zhao, M; Edger, PP; Chelaifa, H; Tack, D; Lassalle, G; Mestiri, I; Schnel, N; Le Paslier, MC; Fan, G; Renault, V; Bayer, PE; Golicz, AA; Manoli, S; Lee, TH; Thi, VH; Chalabi, S; Hu, Q; Fan, C; Tollenaere, R; Lu, Y; Battail, C; Shen, J; Sidebottom, CH; Wang, X; Canaguier, A; Chauveau, A; Bérard, A; Deniot, G; Guan, M; Liu, Z; Sun, F; Lim, YP; Lyons, E; Town, CD; Bancroft, I; Wang, X; Meng, J; Ma, J; Pires, JC; King, GJ; Brunel, D; Delourme, R; Renard, M; Aury, JM; Adams, KL; Batley, J; Snowdon, RJ; Tost, J; Edwards, D; Zhou, Y; Hua, W; Sharpe, AG; Paterson, AH; Guan, C; Wincker, P (22 August 2014). "Plant genetics. Early allopolyploid evolution in the post-Neolithic Brassica napus oilseed genome". Science. 345 (6199): 950–3. doi:10.1126/science.1253435. PMID 25146293. S2CID 206556986.
  6. ^ a b Yang, J; Liu, D; Wang, X; Ji, C; Cheng, F; Liu, B; Hu, Z; Chen, S; Pental, D; Ju, Y; Yao, P; Li, X; Xie, K; Zhang, J; Wang, J; Liu, F; Ma, W; Shopan, J; Zheng, H; Mackenzie, SA; Zhang, M (October 2016). "The genome sequence of allopolyploid Brassica juncea and analysis of differential homoeolog gene expression influencing selection". Nature Genetics. 48 (10): 1225–32. doi:10.1038/ng.3657. PMID 27595476.
  7. ^ Martin A. Lysak; Kwok Cheung; Michaela Kitschke & Petr Bu (October 2007). "Ancestral Chromosomal Blocks Are Triplicated in Brassiceae Species with Varying Chromosome Number and Genome Size" (PDF). Plant Physiology. 145 (2): 402–10. doi:10.1104/pp.107.104380. PMC 2048728. PMID 17720758. Retrieved 2010-08-22.
  8. ^ Murat, Florent; Louis, Alexandra; Maumus, Florian; Armero, Alix; Cooke, Richard; Quesneville, Hadi; Crollius, Hugues Roest; Salse, Jerome (December 2015). "Understanding Brassicaceae evolution through ancestral genome reconstruction". Genome Biology. 16 (1): 262. doi:10.1186/s13059-015-0814-y. PMC 4675067. PMID 26653025.
  9. ^ Chen, Sheng; Nelson, Matthew N.; Chèvre, Anne-Marie; Jenczewski, Eric; Li, Zaiyun; Mason, Annaliese S.; Meng, Jinling; Plummer, Julie A.; Pradhan, Aneeta; Siddique, Kadambot H. M.; Snowdon, Rod J.; Yan, Guijun; Zhou, Weijun; Cowling, Wallace A. (2011-11-01). "Trigenomic Bridges for Brassica Improvement". Critical Reviews in Plant Sciences. 30 (6): 524–547. doi:10.1080/07352689.2011.615700. ISSN 0735-2689. S2CID 84504896.
  10. ^ Yang, Su; Chen, Sheng; Zhang, Kangni; Li, Lan; Yin, Yuling; Gill, Rafaqat A.; Yan, Guijun; Meng, Jinling; Cowling, Wallace A.; Zhou, Weijun (2018-08-28). "A High-Density Genetic Map of an Allohexaploid Brassica Doubled Haploid Population Reveals Quantitative Trait Loci for Pollen Viability and Fertility". Frontiers in Plant Science. 9: 1161. doi:10.3389/fpls.2018.01161. ISSN 1664-462X. PMC 6123574. PMID 30210508.
  11. ^ a b Gaebelein, Roman; Mason, Annaliese S. (2018-09-03). "Allohexaploids in the Genus Brassica". Critical Reviews in Plant Sciences. 37 (5): 422–437. doi:10.1080/07352689.2018.1517143. ISSN 0735-2689. S2CID 91439428.
  12. ^ Kumari P, Singh KP, Kumar S, Yadava DK (2020). "Development of a Yellow-Seeded Stable Allohexaploid Brassica Through Inter-Generic Somatic Hybridization With a High Degree of Fertility and Resistance to Sclerotinia sclerotiorum". Front Plant Sci. 11: 575591. doi:10.3389/fpls.2020.575591. PMC 7732669. PMID 33329636.{{cite journal}}: CS1 maint: multiple names: authors list (link)

January 01, 1970
triangle, triangle, theory, about, evolution, relationships, among, most, commonly, known, members, plant, genus, brassica, theory, states, that, genomes, three, ancestral, diploid, species, brassica, combined, create, three, common, tetraploid, vegetables, oi. The triangle of U uː OO is a theory about the evolution and relationships among the six most commonly known members of the plant genus Brassica The theory states that the genomes of three ancestral diploid species of Brassica combined to create three common tetraploid vegetables and oilseed crop species 1 It has since been confirmed by studies of DNA and proteins 2 The triangle of U diagram showing the genetic relationships among six species of the genus Brassica Chromosomes from each of the genomes A B and C are represented by different colours The theory is summarized by a triangular diagram that shows the three ancestral genomes denoted by AA BB and CC at the corners of the triangle and the three derived ones denoted by AABB AACC and BBCC along its sides The theory was first published in 1935 by Woo Jang choon 3 a Korean Japanese botanist writing under the Japanized name U Nagaharu 4 Woo made synthetic hybrids between the diploid and tetraploid species and examined how the chromosomes paired in the resulting triploids Contents 1 Woo s theory 2 Further relationships 2 1 Allohexaploid species 3 See also 4 ReferencesWoo s theory editThe six species are Genomes Chr count Species Description Diploid AA 2n 2x 20 Brassica rapa syn B campestris turnip napa cabbage bok choi BB 2n 2x 16 Brassica nigra black mustard CC 2n 2x 18 Brassica oleracea cabbage kale broccoli Brussels sprouts cauliflower kohlrabi Tetraploid AABB 2n 4x 36 Brassica juncea Brown mustard AACC 2n 4x 38 Brassica napus rapeseed rutabaga BBCC 2n 4x 34 Brassica carinata Ethiopian mustard The code in the Chr count column specifies the total number of chromosomes in each somatic cell and how it relates to the number n of chromosomes in each full genome set which is also the number found in the pollen or ovule and the number x of chromosomes in each component genome For example each somatic cell of the tetraploid species Brassica napus with letter tags AACC and count 2n 4x 38 contains two copies of the A genome each with 10 chromosomes and two copies of the C genome each with 9 chromosomes which is 38 chromosomes in total That is two full genome sets one A and one C hence 2n 38 which means n 19 the number of chromosomes in each gamete It is also four component genomes two A and two C hence 4x 38 2 The three diploid species exist in nature but can easily interbreed because they are closely related This interspecific breeding allowed for the creation of three new species of tetraploid Brassica 3 Critics however consider the geological separation too large These are said to be allotetraploid containing four genomes from two or more different species more specifically amphidiploid with two genomes each from two diploid species 2 Further relationships editThe framework proposed by Woo although backed by modern studies leaves open questions about the time and place of hybridization and which species is the maternal or paternal parent B napus AACC is dated to have originated about 8 000 5 or 38 000 51 000 6 years ago The homologous part of its constituent chromosomes has crossed over in many cultivars 5 B juncea AABB is estimated to have originated 39 000 55 000 years ago 6 As of 2020 research on organellar genomes shows that B nigra BB is likely the mother of B carinata BBCC and that B rapa AA likely mothered B juncea The situation with B napus AACC is more complex some specimens have a rapa like organellar genome while the rest indicate an ancient unidentified maternal plant 2 Data from molecular studies indicate the three diploid species are themselves paleohexaploids 7 8 Allohexaploid species edit In 2011 and 2018 novel allohexaploids AABBCC located at the center of the triangle of U were created by different means 9 10 11 for example by crossing B rapa AA with B carinata BBCC or B nigra BB with B napus AACC or B oleracea CC with B juncea AABB followed by chromosome duplication of the triploid ABC offspring to generate doubled haploid AABBCC offspring 11 In addition two stable allohexaploid AABBSS intergeneric hybrids between Indian mustard B juncea AABB and white mustard Sinapis alba SS were created in 2020 by protoplast fusion 12 See also editCultivar HybridisationReferences edit Jules Janick 2009 Plant Breeding Reviews Vol 31 Wiley p 56 ISBN 978 0 470 38762 7 a b c d Xue JY Wang Y Chen M Dong S Shao ZQ Liu Y 2020 Maternal Inheritance of U s Triangle and Evolutionary Process of Brassica Mitochondrial Genomes Frontiers in Plant Science 11 805 doi 10 3389 fpls 2020 00805 PMC 7303332 PMID 32595682 Comparative genomic analyses can assign the subgenomes of the allotetraploids B juncea and B napus with their diploid parental taxa and the results were in agreement with U s triangle Chalhoub et al 2014 Yang et al 2016a a b Nagaharu U 1935 Genome analysis in Brassica with special reference to the experimental formation of B napus and peculiar mode of fertilization Japan J Bot 7 389 452 인터넷 과학신문 사이언스 타임즈 in Korean Archived from the original on 2007 09 27 a b Chalhoub B Denoeud F Liu S Parkin IA Tang H Wang X Chiquet J Belcram H Tong C Samans B Correa M Da Silva C Just J Falentin C Koh CS Le Clainche I Bernard M Bento P Noel B Labadie K Alberti A Charles M Arnaud D Guo H Daviaud C Alamery S Jabbari K Zhao M Edger PP Chelaifa H Tack D Lassalle G Mestiri I Schnel N Le Paslier MC Fan G Renault V Bayer PE Golicz AA Manoli S Lee TH Thi VH Chalabi S Hu Q Fan C Tollenaere R Lu Y Battail C Shen J Sidebottom CH Wang X Canaguier A Chauveau A Berard A Deniot G Guan M Liu Z Sun F Lim YP Lyons E Town CD Bancroft I Wang X Meng J Ma J Pires JC King GJ Brunel D Delourme R Renard M Aury JM Adams KL Batley J Snowdon RJ Tost J Edwards D Zhou Y Hua W Sharpe AG Paterson AH Guan C Wincker P 22 August 2014 Plant genetics Early allopolyploid evolution in the post Neolithic Brassica napus oilseed genome Science 345 6199 950 3 doi 10 1126 science 1253435 PMID 25146293 S2CID 206556986 a b Yang J Liu D Wang X Ji C Cheng F Liu B Hu Z Chen S Pental D Ju Y Yao P Li X Xie K Zhang J Wang J Liu F Ma W Shopan J Zheng H Mackenzie SA Zhang M October 2016 The genome sequence of allopolyploid Brassica juncea and analysis of differential homoeolog gene expression influencing selection Nature Genetics 48 10 1225 32 doi 10 1038 ng 3657 PMID 27595476 Martin A Lysak Kwok Cheung Michaela Kitschke amp Petr Bu October 2007 Ancestral Chromosomal Blocks Are Triplicated in Brassiceae Species with Varying Chromosome Number and Genome Size PDF Plant Physiology 145 2 402 10 doi 10 1104 pp 107 104380 PMC 2048728 PMID 17720758 Retrieved 2010 08 22 Murat Florent Louis Alexandra Maumus Florian Armero Alix Cooke Richard Quesneville Hadi Crollius Hugues Roest Salse Jerome December 2015 Understanding Brassicaceae evolution through ancestral genome reconstruction Genome Biology 16 1 262 doi 10 1186 s13059 015 0814 y PMC 4675067 PMID 26653025 Chen Sheng Nelson Matthew N Chevre Anne Marie Jenczewski Eric Li Zaiyun Mason Annaliese S Meng Jinling Plummer Julie A Pradhan Aneeta Siddique Kadambot H M Snowdon Rod J Yan Guijun Zhou Weijun Cowling Wallace A 2011 11 01 Trigenomic Bridges for Brassica Improvement Critical Reviews in Plant Sciences 30 6 524 547 doi 10 1080 07352689 2011 615700 ISSN 0735 2689 S2CID 84504896 Yang Su Chen Sheng Zhang Kangni Li Lan Yin Yuling Gill Rafaqat A Yan Guijun Meng Jinling Cowling Wallace A Zhou Weijun 2018 08 28 A High Density Genetic Map of an Allohexaploid Brassica Doubled Haploid Population Reveals Quantitative Trait Loci for Pollen Viability and Fertility Frontiers in Plant Science 9 1161 doi 10 3389 fpls 2018 01161 ISSN 1664 462X PMC 6123574 PMID 30210508 a b Gaebelein Roman Mason Annaliese S 2018 09 03 Allohexaploids in the Genus Brassica Critical Reviews in Plant Sciences 37 5 422 437 doi 10 1080 07352689 2018 1517143 ISSN 0735 2689 S2CID 91439428 Kumari P Singh KP Kumar S Yadava DK 2020 Development of a Yellow Seeded Stable Allohexaploid Brassica Through Inter Generic Somatic Hybridization With a High Degree of Fertility and Resistance to Sclerotinia sclerotiorum Front Plant Sci 11 575591 doi 10 3389 fpls 2020 575591 PMC 7732669 PMID 33329636 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Retrieved from https en wikipedia org w index php title Triangle of U amp oldid 1200818172, wikipedia, wiki, book, books, library,

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