The mechanism of origin of Robertsonian translocations was investigated in plants monosomic for chromosome 1A of wheat and 1Ht of Elymus trachycaulus by GISH. Chromosomes 1A and 1Ht stayed univalent in all metaphase I cells analyzed, suggesting that Robertsonian translocations do not originate from meiotic recombination in centromeric regions with shared DNA sequence homology. At ana-/telophase I, the 1Ht and 1A univalents underwent either chromosome or chromatid segregation and misdivided in 6–7% of the pollen mother cells. None of the ana-/telophases I analyzed had Robertsonian translocations, which were only observed in 2% of the “half tetrads” at ana-/telophase II. The frequency of Robertsonian translocations observed at ana-/telophase II corresponds well with the number of Robertsonian translocations (1–4%) detected in progenies derived from plants monosomic for group-1 chromosomes of wheat (1A, 1B, and 1D) and 1Ht of E. trachycaulus. Our data suggest that Robertsonian translocations arise from centric misdivision of univalents at ana-/telophase I, followed by segregation of the derived telocentric chromosomes to the same nucleus, and fusion of the broken ends during the ensuing interkinesis.   

1.
Argon-Alcaide L, Miller T, Schwarzacher T, Reader S, Moore G: A cereal centromeric sequence. Chromosoma 105:261–268 (1996).
2.
Badaeva ED, Jiang J, Gill BS: Detection of intergenomic translocations with centromeric and noncentromeric breakpoints in Triticum araraticum: mechanism of origin and adaptive significance. Genome 38:976–981 (1995).
3.
Bandyopadhyay R, Heller A, Knox-DuBois C, McCaskill C, Berend SA, Page SL, Shaffer LG: Parental origin and timing of de novo Robertsonian translocation formation. Am J Hum Genet 71:1456–1462 (2002).
4.
Chin L, Artandi SE, Shen Q, Tam A, Lee SL, Gottlieb GJ, Greider CW, DePinho RA: p53 deficiency rescues the adverse effects of telomerase loss and cooperates with telomere dysfunction to accelerate carcinogenesis. Cell 97:527–538 (1999).
5.
Couteau F, Belzile F, Harlow C, Grandjean O, Vezon D, Doutriaux M-P: Random chromosome segregation without meiotic arrest in both male and female meiocytes of a dmc1 mutant of Arabidopsis. Plant Cell 11:1623–1634 (1999).
6.
Darlington CD: Misdivision and the genetics of the centromere. J Genet 37:341–364 (1939).
7.
Davies PA, Pallotta MA, Driscoll CJ: Centric fusion between nonhomologous rye chromosomes in wheat. Can J Genet Cytol 27:627–632 (1985).
8.
Francki MG: Identification of Bilby, a diverged centromeric Ty1-copia retrotransposon family from cereal rye (Secale cereale L.). Genome 44:266–274 (2001).
9.
Friebe B, Kynast RG, Zhang P, Qi LL, Dhar M, Gill BS: Chromosome addition by telomeric repeats in wheat occurs during the first mitotic divisions of the sporophyte and is a gradual process. Chromosome Res 9:137–146 (2001).
10.
Gill BS, Friebe B, Endo TR: Karyotype and nomenclature system for description of chromosome bands and structural aberrations in wheat (Triticum aestivum). Genome 34:830–839 (1991).
11.
Heller K, Kilian A, Piatyzek MA, Kleinhofs A: Telomerase activity in plant extracts. Theor Appl Genet 252:342–345 (1996).
12.
Holmquist GP, Dancis B: Telomere replication, kinetochore organizers, and satellite DNA evolution. Proc Natl Acad Sci USA 76:4566–4570 (1979).
13.
Jiang J, Morris KLD, Gill BS: Introgression of Elymus trachycaulus chromatin into common wheat. Chromosome Res 2:3–13 (1994).
14.
Jiang J, Nasuda S, Dong F, Scherrer CW, Woo SS, Wing RA, Gill BS, Ward DC: A conserved repetitive DNA element located in the centromeres of cereal chromosomes. Proc Natl Acad Sci USA 93:14210–14213 (1996).
15.
Jones K: Aspects of chromosome evolution in higher plants, in Woolhouse HW (ed): Advances in Botanical Research, Vol. 6, pp 119–193 (Academic Press, New York 1978).
16.
Kaszás E, Birchler JA: Misdivision analysis of centromere structure in maize. EMBO J 15:5246–5255 (1996).
17.
Lukaszewski AJ: Reconstruction in wheat of complete chromosomes 1B and 1R from the 1RS·1BL translocation of “Kavkas” origin. Genome 36:821–824 (1993).
18.
Lukaszewski AJ: Manipulation of the genome by chromosome breakage, in Gill BS, Raupp WJ (eds): Proceedings of the US-Japan Symposium, Classical and Molecular Cytogenetic Analysis, pp 136–139, 21–23 March 1994, Manhattan, Kansas, USA (1994).
19.
Lukaszewski AJ: Further manipulation by centric misdivision of the 1RS·1BL translocation in wheat. Euphytica 94:257–261 (1997).
20.
Lukaszewski AJ, Gustafson JP: Translocations and modifications of chromosomes in triticale × wheat hybrids. Theor Appl Genet 64:239–248 (1983).
21.
Marais GF, Marais AS: The derivation of compensating translocations involving homoeologous group 3 chromosomes of wheat and rye. Euphytica 79:75–80 (1994).
22.
Miller JT, Dong F, Jackson SA, Song J, Jiang J: Retrotransposon-related DNA sequences in the centromere of grass chromosomes. Genetics 150:1615–1623 (1998).
23.
Morris KLD, Raupp WJ, Gill BS: Isolation of 1Ht genome additions from polyploidy Elymus trachycaulus (StStHtHt) into common wheat (Triticum aestivum). Genome 33:15–22 (1990).
24.
Morris R, Schmidt JW, Johnson VA: Aneuploid studies at the University of Nebraska. EWAC Newsl 2:55–56 (1969).
25.
Page SL, Shin J-C, Han J-Y, Choo KHA, Shaffer LG: Breakpoint diversity illustrates distinct mechanisms for Robertsonian translocation formation. Hum Mol Genet 5:1279–1288 (1996).
26.
Presting GG, Malysheva L, Fuchs J, Schubert I: A Ty3/gypsy retrotransposon-like sequence localizes to the centromeric regions of cereal chromosomes. Plant J 16:721–728 (1998).
27.
Preuss SB, Britt AB: A DNA-damage-induced cell cycle checkpoint in Arabidopsis. Genetics 164:323–334 (2003).
28.
Robertson WMRB: Chromosome studies. I. Taxonomic relationships shown in the chromosomes of Tettegidae and Acrididiae: V-shaped chromosomes and their significance in Acrididiae, Locustidae and Grillidae: chromosomes and variation. J Morphol 27:179–331 (1916).
29.
Sanchez-Monge E, Mac Key J: On the origin of subcompatoids in Triticum vulgare. Hereditas 34:321–337 (1948).
30.
Schubert I, Rieger R: A new mechanism for altering chromosome number during karyotype evolution. Theor Appl Genet 70:213–221 (1985).
31.
Schubert I, Rieger R, Fuchs J: Alteration of basic chromosome number by fusion-fission cycles. Genome 38:1289–1292 (1995).
32.
Sears ER: Misdivision of univalents in common wheat. Chromosoma 4:535–550 (1952).
33.
Sears LMS: Misdivision of five different 3B monosomics in Chinese Spring wheat. Proc 4th Int Wheat Genet Symp, Columbia, MO, pp 739–743 (1973).
34.
Slijepcevic P: Telomeres and mechanisms of Robertsonian fusion. Chromosoma 107:136–140 (1998).
35.
Steinitz-Sears LM: Somatic instability of telocentric chromosomes in wheat and the nature of the centromere. Genetics 54:241–248 (1966).
36.
Sullivan BA, Jenkins LS, Karson EM, Leana-Cox J, Schwartz S: Evidence for structural heterogeneity from molecular cytogenetic analysis of dicentric Robertsonian translocations. Am J Hum Genet 59:167–175 (1996).
37.
Vega JM, Feldman M: Effect of the pairing gene Ph1 on centromere division in common wheat. Genetics 148:1285–1294 (1998).
38.
White MJD: Animal Cytology and Evolution, 3rd ed. (Cambridge University Press, London 1973).
39.
Zhang P, Friebe B, Lukaszewski AJ, Gill BS: The centromere structure in Robertsonian wheat-rye translocation chromosomes indicates that centric breakage-fusion can occur at different positions within the primary constriction. Chromosoma 110:335–344 (2001).
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