Physical size of the S locus region defined by genetic recombination and genome sequencing in Ipomoea trifida, Convolvulaceae
Physical size of the S locus region defined by genetic recombination and genome sequencing in Ipomoea trifida, Convolvulaceae
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DOI：
10.1007/s00497-007-0044-x
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发表时间：
2007-06-01
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通讯作者：
Kowyama, Yasuo
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文献类型：
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作者：
Rahman, Md. Habibur;Tsuchiya, Tohru;Kowyama, Yasuo
空心菜属（旋花科）孢子体自交不亲和性（SSI）受单一多态性S位点控制。我们先前已经分析了跨越S-1单倍型的S位点的约300 kb区域的基因组序列，并表征了该位点周围的基因组结构。在这里，我们进一步定义的物理大小的S基因座区域通过映射重组断点，基于从重组体的基因组DNA扩增的PCR片段的序列分析。从重组分析，S-1单倍型的S基因座被界定为0.23 cM的连锁图谱的区域，这对应于212 kb的最大物理大小。为了分析S单倍型之间基因组组织的差异，对跨越约67 kb的S（10）单倍型的fosmid重叠群进行测序。与S-1基因组序列的比较显示，S-1和S-10单倍型的S单倍型特异性趋异区（SDRs）分别跨越50.7和34.5 kb，它们的侧翼区显示出高度的序列相似性。在S-10单倍型的测序区域中，发现12个预测的开放阅读框（ORF）中的5个位于发散区域，并显示两个S单倍型之间的基因共线性组织。基于SDR的大小，估计S基因座的物理大小在牵牛属中落在34-50 kb的范围内。
Sporophytic self-incompatibility (SSI) in the genus Ipomoea (Convolvulaceae) is controlled by a single polymorphic S locus. We have previously analyzed genomic sequences of an approximately 300 kb region spanning the S locus of the S-1 haplotype and characterized the genomic structure around this locus. Here, we further define the physical size of the S locus region by mapping recombination breakpoints, based on sequence analysis of PCR fragments amplified from the genomic DNA of recombinants. From the recombination analysis, the S locus of the S-1 haplotype was delimited to a 0.23 cM region of the linkage map, which corresponds to a maximum physical size of 212 kb. To analyze differences in genomic organization between S haplotypes, fosmid contigs spanning approximately 67 kb of the S (10) haplotype were sequenced. Comparison with the S-1 genomic sequence revealed that the S haplotype-specific divergent regions (SDRs) spanned 50.7 and 34.5 kb in the S-1 and S-10 haplotypes, respectively and that their flanking regions showed a high sequence similarity. In the sequenced region of the S-10 haplotype, five of the 12 predicted open reading frames (ORFs) were found to be located in the divergent region and showed co-linear organization of genes between the two S haplotypes. Based on the size of the SDRs, the physical size of the S locus was estimated to fall within the range 34-50 kb in Ipomoea.