Ross K, Ma X-F, Mahmoud A A, Layton J, Milla M A Rodriguez, Chikmawati T, Ramalingam J, Feril O, Pathan M S, Momirovic G Surlan, Kim S, Chema K, Fang P, Haule L, Struxness H, Birkes J, Yaghoubian C, Skinner R, McAllister J, Nguyen V, Qi L L, Echalier B, Gill B S, Linkiewicz A M, Dubcovsky J, Akhunov E D, Dvorák J, Dilbirligi M, Gill K S, Peng J H, Lapitan N L V, Bermudez-Kandianis C E, Sorrells M E, Hossain K G, Kalavacharla V, Kianian S F, Lazo G R, Chao S, Anderson O D, Gonzalez-Hernandez J, Conley E J, Anderson J A, Choi D-W, Fenton R D, Close T J, McGuire P E, Qualset C O, Nguyen H T, Gustafson J P
Department of Agronomy, University of Missouri, Columbia, Missouri 65211, USA.
Genetics. 2004 Oct;168(2):651-63. doi: 10.1534/genetics.104.034827.
A total of 1918 loci, detected by the hybridization of 938 expressed sequence tag unigenes (ESTs) from 26 Triticeae cDNA libraries, were mapped to wheat (Triticum aestivum L.) homoeologous group 4 chromosomes using a set of deletion, ditelosomic, and nulli-tetrasomic lines. The 1918 EST loci were not distributed uniformly among the three group 4 chromosomes; 41, 28, and 31% mapped to chromosomes 4A, 4B, and 4D, respectively. This pattern is in contrast to the cumulative results of EST mapping in all homoeologous groups, as reported elsewhere, that found the highest proportion of loci mapped to the B genome. Sixty-five percent of these 1918 loci mapped to the long arms of homoeologous group 4 chromosomes, while 35% mapped to the short arms. The distal regions of chromosome arms showed higher numbers of loci than the proximal regions, with the exception of 4DL. This study confirmed the complex structure of chromosome 4A that contains two reciprocal translocations and two inversions, previously identified. An additional inversion in the centromeric region of 4A was revealed. A consensus map for homoeologous group 4 was developed from 119 ESTs unique to group 4. Forty-nine percent of these ESTs were found to be homoeologous to sequences on rice chromosome 3, 12% had matches with sequences on other rice chromosomes, and 39% had no matches with rice sequences at all. Limited homology (only 26 of the 119 consensus ESTs) was found between wheat ESTs on homoeologous group 4 and the Arabidopsis genome. Forty-two percent of the homoeologous group 4 ESTs could be classified into functional categories on the basis of blastX searches against all protein databases.
利用一套缺失系、双端体和缺体-四体材料，将来自26个小麦族cDNA文库的938个表达序列标签单基因（EST）杂交检测到的总共1918个位点定位到小麦（Triticum aestivum L.）第4部分同源群染色体上。这1918个EST位点在第4部分同源群的3条染色体上分布不均匀；分别有41%、28%和31%的位点定位到4A、4B和4D染色体上。这种模式与其他地方报道的所有部分同源群EST定位的累积结果相反，后者发现定位到B基因组的位点比例最高。这1918个位点中的65%定位到第4部分同源群染色体的长臂上，而35%定位到短臂上。除了4DL外，染色体臂的远端区域比近端区域显示出更多的位点。本研究证实了先前鉴定的4A染色体含有两个相互易位和两个倒位的复杂结构。还揭示了4A染色体着丝粒区域的一个额外倒位。利用4组特有的119个EST构建了第4部分同源群的一致性图谱。发现这些EST中有49%与水稻第3染色体上的序列同源，12%与其他水稻染色体上的序列匹配，39%与水稻序列完全不匹配。在第4部分同源群的小麦EST与拟南芥基因组之间发现了有限的同源性（119个一致性EST中只有26个）。根据对所有蛋白质数据库的blastX搜索，第4部分同源群的EST中有42%可以分类到功能类别中。
