【正文】
隨著分子生物學(xué)技術(shù)的發(fā)展,現(xiàn)在 DNA分子標記技術(shù)已有數(shù)十種,廣泛應(yīng)用于遺傳育種、基因組作圖、基因定位、物種親緣關(guān)系鑒別、基因庫構(gòu)建、基因克隆等方面。 ?蛋白質(zhì)標記包括動 植物蛋白 、 同工酶 及 等位酶 ?理想的分子標記: * ** * 雜合子的一對等位基因各自都具有自己的表型效應(yīng),稱為共顯性( codominance) ** 基因多效性( gene pleiotropism) :一個基因產(chǎn)生多種表型效應(yīng)的現(xiàn)象。植物 DNA 分子標記 分子標記的概念 ?廣義的分子標記 ( molecular marker):可遺傳的并可檢測的 DNA序列或蛋白。包括蛋白質(zhì)標記和 DNA標記(狹義的分子標記)。 DNA分子標記( DNA molecular marker)直接在 DNA分子水平上檢測生物間的差異,是 DNA水平上遺傳變異的直接反應(yīng)。 DNA分子標記大多以電泳譜帶的形式表現(xiàn),分為非 PCR依賴的分子標記 (基于 Southern 雜交技術(shù)的分子標記 )和 PCR依賴的分子標記 。 分子雜交 :由具有互補堿基順序的任何兩條 單鏈 核酸分子片斷形成 雙鏈 的過程。 In situ hybridization ? For in situ hybridization, a tissue sample is incubated with a labeled nucleic acid probe, excess probe is washed away and the location of hybridized probe is examined. ? The technique enables the spatial localization of gene expression to be determined as well as the location of individual genes on chromosomes. b c d a Fig. 5 GISH images of chromosomes of tetraploid and diploid Festulolium progenies. The DNA of L. perenne was used as probe, and shown as blue color. The chromosomes of F. pratensis were shown as pale blue color. Translocation breakpoints are indicated in a and c by arrows. (a) Bx350184, a 28chromosome genome with at least 14 intergeneric translocations, some of which have two breakpoints in an arm (arrows). Bar: 10 μm. (b) Bx351160, a 28chromosome genome with intergeneric translocations. Bar: 20 μm. (c) Bx350177 with fertile pollen, a 28chromosome genom