Physical Mapping Integrated with Syntenic Analysis to Characterize the Gene Space of the Long Arm of Wheat Chromosome 1A

Detailed physical mapping of markers from rice chromosome 9, and from syntenous (at the genetic level) regions of other cereal genomes, has resulted in rice yeast artificial chromosome (YAC) contigs spanning parts of rice 9. This physical mapping, together with comparative genetic mapping, has demonstrated that synteny has been largely maintained between the genomes of several cereals at the level of contiged YACs. Markers located in one region of rice chromosome 9 encompassed by the YAC contigs have exhibited restriction fragment length polymorphism (RFLP) using deletion lines for the Ph1 locus. This has allowed demarcation of the region of rice chromosome 9 syntenous with the ph1b and ph1c deletions in wheat chromosome 5B. A group of probes located in wheat homoeologous group 5 and barley chromosome 5H, however, have synteny with rice chromosomes other than 9. This suggests that the usefulness of comparative trait analysis and of the rice genome as a tool to facilitate gene isolation will differ from one region to the next, and implies that the rice genome is more ancestral in structure than those of the Triticeae.

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Genetic and physical mapping of homoeologous recombination points involving wheat chromosome 2B and rye chromosome 2R

Genome ◽

10.1139/g03-089 ◽

2004 ◽

Vol 47 (1) ◽

pp. 36-45 ◽

Cited By ~ 59

Author(s):

A J Lukaszewski ◽

K Rybka ◽

V Korzun ◽

S V Malyshev ◽

B Lapinski ◽

...

Keyword(s):

Homologous Recombination ◽

Genetic Map ◽

Physical Mapping ◽

Dna Sequences ◽

Wheat Chromosome ◽

Genetic Maps ◽

Homoeologous Recombination ◽

Chromosome Engineering ◽

Genetic And Physical Mapping ◽

Structural Differences

Wide hybrids have been used in generating genetic maps of many plant species. In this study, genetic and physical mapping was performed on ph1b-induced recombinants of rye chromosome 2R in wheat (Triticum aestivum L.). All recombinants were single breakpoint translocations. Recombination 2RS–2BS was absent from the terminal and the pericentric regions and was distributed randomly along an intercalary segment covering approximately 65% of the arm's length. Such a distribution probably resulted from structural differences at the telomeres of 2RS and wheat 2BS arm that disrupted telomeric initiation of pairing. Recombination 2RL–2BL was confined to the terminal 25% of the arm's length. A genetic map of homoeologous recombination 2R–2B was generated using relative recombination frequencies and aligned with maps of chromosomes 2B and 2R based on homologous recombination. The alignment of the short arms showed a shift of homoeologous recombination toward the centromere. On the long arms, the distribution of homoeologous recombination was the same as that of homologous recombination in the distal halves of the maps, but the absence of multiple crossovers in homoeologous recombination eliminated the proximal half of the map. The results confirm that homoeologous recombination in wheat is based on single exchanges per arm, indicate that the distribution of these single homoeologous exchanges is similar to the distribution of the first (distal) crossovers in homologues, and suggest that successive crossovers in an arm generate specific portions of genetic maps. A difference in the distribution of recombination between the short and long arms indicates that the distal crossover localization in wheat is not dictated by a restricted distribution of DNA sequences capable of recombination but by the pattern of pairing initiation, and that can be affected by structural differences. Restriction of homoeologous recombination to single crossovers in the distal part of the genetic map complicates chromosome engineering efforts targeting genes in the proximal map regions.Key words: homoeologous recombination, genetic mapping, RFLP, RAPD, wheat, rye.

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Dissection and physical mapping of wheat chromosome 7B by inducing meiotic recombination with its homoeologues in Aegilops speltoides and Thinopyrum elongatum

Theoretical and Applied Genetics ◽

10.1007/s00122-020-03680-3 ◽

2020 ◽

Vol 133 (12) ◽

pp. 3455-3467

Author(s):

Mingyi Zhang ◽

Wei Zhang ◽

Xianwen Zhu ◽

Qing Sun ◽

Changhui Yan ◽

...

Keyword(s):

Physical Mapping ◽

Meiotic Recombination ◽

Wheat Chromosome ◽

Aegilops Speltoides ◽

Thinopyrum Elongatum

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Identification of wheat-barley translocations by sequential GISH and two-colour FISH in combination with the use of genetically mapped barley SSR markers

Genome ◽

10.1139/g02-068 ◽

2002 ◽

Vol 45 (6) ◽

pp. 1238-1247 ◽

Cited By ~ 35

Author(s):

E D Nagy ◽

M Molnár-Láng ◽

G Linc ◽

L Láng

Keyword(s):

Ssr Markers ◽

Physical Mapping ◽

Ssr Marker ◽

Molecular Genetic ◽

Wheat Chromosome ◽

Translocation Breakpoints ◽

Correct Location ◽

Translocation Lines ◽

Gish And Fish ◽

Chromosome Segments

Five wheatbarley translocations in a wheat background were characterized through the combination of cytogenetic and molecular genetic approaches. The wheat chromosome segments involved in the translocations were identified using sequential GISH and two-colour FISH with the probes pSc119.2 and pAs1. The barley chromatin in these lines was identified using SSR markers. A total of 45 markers distributed over the total barley genome were selected from a recently published linkage map of barley and tested on the translocation lines. The following translocations were identified: 2DS.2DL1HS, 3HS.3BL, 6BS.6BL4HL, 4D5HS, and 7DL.7DS5HS. Wheatbarley disomic and ditelosomic addition lines for the chromosomes 3HS, 4H, 4HL, 5H, 5HL, and 6HS were used to determine the correct location of 21 markers and the position of the centromere. An intragenomic translocation breakpoint was detected on the short arm of the barley chromosome 5H with the help of SSR marker analysis. Physical mapping of the SSR markers on chromosomes 1H and 5H was carried out using the intragenomic and the interspecific translocation breakpoints, as well as the centromere, as physical landmarks.Key words: wheat-barley translocations, sequential GISH and FISH, SSR markers, physical mapping.

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