Identification of a Molecular Marker and Chromosome Mapping of the 5S rRNA Gene inAllium sacculiferum
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The 5S rRNA gene in higher eukaryotes is organized into repeated units of tandem array that comprise a conserved 120-bp coding region and a non-transcribed spacer (NTS) of variable length with nucleotides. The allotetraploid genome ofAllium sacculiferum consists of two unknown diploids (2n=32). Analyses have not been successful toward clarifying the origin of each genome due to their similar chromosome morphology and unmatched C-banding patterns. We PCR-amplified the coding and NTS regions of its 5S rRNA genes, cloned them into vectors, and determined their DNA sequences. Interestingly, the aligned sequences of the NTS clones could be divided into two distinctive groups based on the existence of a 3-bp CCT insertion/deletion at the beginning of the NTS region. This feature makes it an important genetic marker for distinguishing the origin of theA. sacculiferum chromosomes. Furthermore, by applying fluorescencein situ hybridization, we located the 5S rRNA gene loci on Chromosomes 5, 7, 8, 9, and 14; their distribution is unique toA. sacculiferum. These data support the idea that one set of this genome has originated from a CCT-containing close relative --A. deltoid-fistulosum -- and that the NTS region may be used as a molecular marker for identifying parental lines for the allotetraploidityof A. sacculiferum.
KeywordsAllium sacculiferum allotetraploid 5S rRNA molecular marker sequence variation
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- Do CS, Seo BB (2000) Phylogenetic relationships amongAllium subg.Rhizihdeum species based on the molecular variation of 5S rRNA genes. Kor J Biol Sci4: 77–85Google Scholar
- Do GS, Seo BB, Ko JM, Lee SH, Park JH, Kim IS, Song SD (1999) Analysis of somaclonal variation through tissue culture and chromosomal localization of rDNA sites by fluorescent in situ hybridization in wildAllium tuberosum and a regenerated variant. Plant Cell Tiss Org Cult57: 113–119CrossRefGoogle Scholar
- Fritsch RM, Friesen N (2002) Evolution, domestication and taxonomy.In HD Ravinovitch, L Currah, eds,Allium Crop Science: Recent Advances. CAB international, Wallingford, England, pp 5–27Google Scholar
- Klaas M (1998) Applications and impact of molecular markers on evolutionary and diversity studies in the genusAllium. Plant Bleed117: 297–308Google Scholar
- Lapitan NLV, Canal MW, Tanksley SD (1989) Somatic chromosome karyotypes of tomato based on in situ hybridization of the TAGI satellite repeat. Genome32: 992–998Google Scholar
- Lewin B (2004) Genes III. Prentice Hall, Pearson Education, Inc., Upper Saddle River, NJ, USAGoogle Scholar
- Mukai Y, Endo TR, Grill BS (1990) Physical mapping of the 18S-26S rRNA multigene family in common wheat. J Hered81: 290–295Google Scholar
- Rogers SO, Bendich AJ (1988) Extraction of DNA from plant tissue,In SB Gelvin, RA Schilperoort, eds, Plant Molecular Manual A6. Kluwer Academic Publishers, Dordrecht, pp 1–10Google Scholar
- Seo BB, Kim HH (1989) Giemsa C-banded karyotypes in two diploid and two tetraploidAllium species. Kor J Bot32: 181–188Google Scholar
- Thompson JD, Higgins DC, Gibson TJ (1994) CLUSTAL W: Improving the sensitivity of progressive multiple alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucl Acids Res16: 486–499Google Scholar