Genome Evolution in Allopolyploid Wheats: Evidence from Low Copy DNA Sequences

异源多倍体小麦的基因组进化：来自低拷贝 DNA 序列的证据

• 批准号: 9508686
• 负责人: Luther Talbert
• 金额: $ 13.5万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9508686&HistoricalAwards=false
• 关键词: Genome; Evolution; Allopolyploid; Wheats; Evidence

9508686 Talbert Many plant species, and some animal species as well, have originated following hybridization between two or more progenitor species. In many cases, both sets of chromosomes in each of the parental (diploid) species are retained in the hybrid, which thus becomes a tetra(allopoly)ploid organism. Many of our common crop plants like wheat, oats, cotton, and tobacco are allopolyploids. The evolution of these species may proceed along pathways that are not open to diploid species. For instance, it has been suggested that allopolyploids are buffered against deleterious mutations more effectively than diploids. One complication in tracing the ancestry of polyploid plant species, however, lies in the finding that some diploid species are themselves hybrid derivatives of past crossings. It is for this reason that polyploid hybrids can be hypothesized to combine multiple parental lines. Drs. Luther Talbert and Matthew Lavin of Montana State University are making imaginative use of new methods of DNA analysis to study the origins of polyploid wheats, and in particular the group designated as 'B' genome wheats. Their work builds upon three converging research enterprises: 1) the development of specific markers of genes on the two arms of each chromosome in wheats; 2) the use of breeding stocks of polyploid wheats that lack a specific chromosome (so-called nullisomic lines); and 3) the search for and maintenance of wild diploid wheats collected in the Middle East. Their studies will test the hypothesis that each genome is actually a composite of chromosomes from several progenitor species, and if so, from which progenitors. The use of single or low copy-number nuclear DNA markers on chromosomes should prove adaptable to other plant systems, in helping to solve the problem of hybrid origins of polyploids.

9508686许多植物物种以及一些动物物种起源于两个或更多祖先物种之间的杂交。在许多情况下，每个亲本(二倍体)物种的两组染色体都保留在杂种中，从而成为一个四倍体(异倍体)有机体。许多我们常见的农作物，如小麦、燕麦、棉花和烟草，都是异源多倍体。这些物种的进化可能沿着二倍体物种不开放的途径进行。例如，已经有人提出，异源多倍体比二倍体更有效地缓冲有害突变。然而，追踪多倍体植物物种祖先的一个复杂之处在于，发现一些二倍体物种本身就是过去杂交的杂交衍生品。正是由于这个原因，可以假设多倍体杂交组合成多个亲本系。蒙大拿州立大学的Luther Talbert博士和Matthew Lavin博士正在富有想象力地利用DNA分析的新方法来研究多倍体小麦的起源，特别是被命名为B基因组小麦的群体。他们的工作建立在三个共同的研究项目上：1)开发小麦每条染色体两臂上的特定基因标记；2)利用缺乏特定染色体的多倍体小麦育种群体(所谓的缺体系)；以及3)寻找和维护在中东采集的野生二倍体小麦。他们的研究将检验这样一个假设，即每个基因组实际上是来自几个祖先物种的染色体的组合，如果是这样的话，来自哪个祖先物种的染色体。在染色体上使用单一或低拷贝数的核DNA标记应被证明适用于其他植物系统，有助于解决多倍体的杂交起源问题。