龙须菜微卫星DNA的初步研究

The Preliminary Study on the Microsatellite DNA of Gracilaria lemaneiformis

为从龙须菜中分离含微卫星DNA的片段采用了2种方法,总共筛选了1 100个克隆。其中应用地高辛标记探针,通过菌落原位杂交方法,筛选得到13个克隆,测序结果显示仅有1个克隆含有微卫星DNA;PCR方法筛选出28个克隆,测序显示有23个克隆含有微卫星DNA。在总共测序的24个克隆中共有77个微卫星序列,每个克隆中含有的微卫星DNA在1～7个不等。核心序列重复次数在10次(含10次)以上的微卫星有38个,重复次数在10～38不等,重复次数在7～9次之间的微卫星有39个。在获得的微卫星序列中GA重复占97%,CA重复仅占3%。完全型微卫星55个,占71.4%;不完全型微卫星21个,占27.3%;复合型微卫星1个,仅占1.3%。龙须菜微卫星DNA的含量较低。

Two methods were exploited to isolate microsatellites DNA containing fragments from Gracilaria lemaneiformis. Totally 1100 clones were screened. Using digoxigenin-labelled probe and clonal in situ hybridization, 13 clones were obtained and sequenced while there was only 1 clone containing microsatellite DNA. Twenty-eight clones were isolated by PCR screening, while 23 of them contained microsatellite DNA. Seventy-seven microsatellite DNA distribution place were found in 24 totally sequenced clones. One to seven microsatellite DNA distribution place were found from each fragment. Among 77 motifs of microsatellite DNA found, 38 contained ≥10 but ≤38 repeats of simple sequence; 39 contained ≥7 but ≤9 repeats of simple sequence. The simple sequences identified included GA （97%） and CA （3%）, while the complex type included 55 perfect （71.4%）, 21 imperfect （27. 3%） and 1 compound （1.3%）. The alga was poor in containing of microsatellite DNA.