胡桃EST-SSR标记的筛选及引物设计

[目的]筛选胡桃的EST—SSR分子标记并对其进行引物设计。[方法]利用生物信息学方法对NCBI网上公开的5213条胡桃（Jug—lans regia Linn．）ESTs序列进行EST—SSR特征分析,利用Primer3．0软件对筛选出的EST序列设计引物。[结果]在ESTs序列中共检索出207个SSR,其中无冗余序列188,检出率为3．97％,平均分布距离为21．12kb,包括92种重复基元,其中以二核苷酸和三核苷酸重复类型为主,分别占总数目的31．40％和35．27％;对随机筛选出的50条SSR引物进行PCR扩增验证,初步筛选出30对引物。[结论]通过对胡桃EST序列中SSR位点的发掘分析,有针对性地设计EST．SSR引物,将为胡桃科EST—SSR分子标记的开发奠定基础。     

应用微卫星标记分析长江流域长吻鮠4个群体的遗传多样性

为了对长江中长吻鮠的遗传多样性和遗传结构进行深入的分析,同时为长江三峡大坝建成后鱼类资源保护提供有效的遗传背景资料,选用8对长吻鮠微卫星引物对长江上游及长江中下游的长吻鮠4个群体进行遗传多样性分析。8对长吻鮠微卫星引物在长吻鮠4个群体共86个样本中扩增出清晰稳定的条带,且个体间表现出不同程度的多态性;长吻鮠4个群体(重庆、石首、武汉、九江)的平均等位基因数分别为7.3、5.6、4.8、3.3,观测杂合度分别为0.732、0.312、0.681、0.877。同时基于遗传距离所进行的聚类分析显示:长江中下游的石首、武汉和九江群体关系较近,而长江上游的重庆群体与中下游的3个群体关系较远。综合来看,长江水系中长吻鮠群体的遗传多样性较贫乏。     

林甸鸡和大骨鸡微卫星DNA标记遗传多样性的比较研究

为了从分子水平上揭示林甸鸡和大骨鸡的群体遗传结构,利用鸡基因组中5个微卫星标记,检测了林甸鸡和大骨鸡群体的遗传多样性。同时探讨了林甸鸡和大骨鸡在国内几个地方鸡种中的系统地位。结果表明,5个微卫星位点共检测到38个等位基因,其中ADL0146位点的等位基因数5个,为最少,而ADL0136和ADL0185两个位点的等位基因数9个,为最多;5个微卫星位点的平均等位基因数为7．6个。林甸鸡群体内比大骨鸡群体有更丰富的遗传多样性。聚类分析结果显示,林甸鸡和大骨鸡与边鸡、日照麻鸡及寿光鸡之间有比较密切的亲缘关系;而林甸鸡和大骨鸡与鲁西斗鸡的亲缘关系均较远。总体而言,该系统聚类结果与7个鸡种的分化与选育历史是一致的。     

Genetic identity and relationships of Iranian apple (Malus?×?domestica Borkh.) cultivars and landraces, wild Malus species and representative old apple cultivars based on simple sequence repeat (SSR) marker analysis

In order to shed light on the role of Iran in apple evolution and domestication, we chose to investigate the relationships of a collection of 159 accessions of wild and domesticated apples including Iranian indigenous apple cultivars and landraces, selected wild species, and old apple scion and rootstock cultivars from different parts of the world. The majority of the wild species belonged to M. sieversii, which is widely believed to be the main maternal wild ancestor of domestic apples, from Kazakhstan and M. orientalis, which is one of the probable minor ancestors of domestic apples, from Turkey and Russia located on the east and west of Iran, respectively. The accessions were assigned into six arbitrary populations for the purpose of generating information on genetic parameters. Nine simple sequence repeat (SSR) loci selected from previous studies in apple were screened over DNA extracted from all the accessions. Results showed that all SSR loci displayed a very high degree of polymorphism with 11–25 alleles per locus. In total, there were 153 alleles across all loci with an average of 17 alleles per locus. The SSR allelic data were then used for estimation of population genetic parameters, including genetic variation statistics, F-statistics, gene flow, genetic identity, genetic distance and then cluster analysis using POPGENE 1.32 software. The F-statistics and gene flow in particular, showed that there was more intra-population than between population variation. The genetic identity and genetic distance estimates, and the dendrogram generated from the un-weighted pair group arithmetic average (UPGMA) method of cluster analysis showed that the Iranian cultivars and landraces were more closely related to M. sieversii from Central Asia (east of Iran) and M. orientalis native to Turkey and Russia than to other accessions of Malus species. Also, the old apple cultivars from different parts of the world have a closer genetic relationship to M. sieversii, M. orientalis and the Iranian apples, than to other wild species. Based on these results, we suggest that the Iranian apples may occupy an intermediate position between the domesticated varieties and wild species. We propose that Iran could be one of the major players in apples’ domestication and transfer from Central Asia to the western countries.     

Counting elusive animals: Comparing field and genetic census of the entire mountain gorilla population of Bwindi Impenetrable National Park, Uganda

Accurate population size estimates are an essential part of every effective management plan for conserving endangered species. However, censusing rare and elusive wild animals is challenging and often relies on counting indirect signs, such as nests or feces. Despite widespread use, the accuracy of such estimates has rarely been evaluated. Here we compare an estimate of population size derived solely from field data with that obtained from a combination of field and genetic data for the critically endangered population of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda. After genotyping DNA from 384 fecal samples at 16 microsatellite loci, the population size estimate was reduced by 10.1% to 302 individuals, compared with 336 gorillas estimated using the traditional nest-count based method alone. We found that both groups and lone silverbacks were double-counted in the field and that individuals constructed multiple nests with an overall rate of 7.8%, resulting in the overestimation of the population size in the absence of genetic data. Since the error associated with the traditional field method exceeded the estimated population growth of 5% in the last 4 years, future genetic censusing will be needed to determine how the population size is changing. This study illustrates that newly improved molecular methods allow fast, efficient and relatively affordable genotyping of several hundred samples, suggesting that genetic censusing can be widely applied to provide accurate and reliable population size estimates for a wide variety of species.     

合浦珠母贝微卫星DNA标记的分离与筛选

[目的]研究合浦珠母贝微卫星DNA标记的分离与筛选。[方法]采用生物素标记的5个探针,用磁珠富集法构建合浦珠母贝基因组微卫星富集文库,并对文库进行筛选、测序与引物多态性筛选。[结果]对500个克隆进行PCR筛选,测序分析发现130个克隆含有微卫星重复单元。序列比对后最终获得109个具有特异微卫星序列的阳性克隆,其中包含179个微卫星DNA结构域。基于微卫星两端的侧翼序列设计并获得了13对能够在合浦珠母贝基因组有效扩增的微卫星引物,其中8对在种群中（n=32）具有扩增多态性,其多态信息含量PIC值在0．239～0．787;等位基因数在2～9个;观测杂合度介于0．22～0．56;期望杂合度的变化范围为0．25～0．83。[结论]这研究为进一步开展合浦珠母贝的遗传分析提供了基础资料。     

利用微卫星标记分析湖羊GDF8区域的遗传多样性

1材料与方法 1．1试验材料与DNA提取2007年,在江苏省苏州市种羊场随机选取成年羊88只,采取耳组织提取DNA,-20℃保存。并记录湖羊的初生重、断奶重和6月龄重。     

42个杂交粳稻亲本SSR指纹图谱的构建及遗传多样性分析

[目的]研究利用SSR技术构建以杂交粳稻亲本为主的SSR指纹图谱。[方法]用48对SSR引物扩增了42个杂交粳稻亲本的基因组DNA,从中筛选出12对具有稳定多态性的引物,推荐为核心引物。建立了42个杂交粳稻亲本×12个核心引物的DNA指纹数据库。[结果]采用类平均法聚类分析计算42个基因型的相似系数,在相似系数0.73处,可将42个杂交粳稻亲本分为5大类。[结论]聚类分析的结果基本反映了品种间的亲缘关系。     

微卫星DNA聚丙烯酰胺凝胶电泳和银染技术的探讨

采用PCR一非变性聚丙烯酰胺凝胶电泳、硝酸银染色检测DNA片段。结果表明,该方法检测DNA具有灵敏度高、背景浅、条带清晰等突出特点。聚丙烯酰胺凝胶电泳后采用银染技术分析,方便快捷,易长期保存,且减小了对人体、环境的毒害作用。     

利用微卫星标记对3个绵羊品种肉用性状多态性的研究

[目的]研究3个绵羊品种肉用性状的多态性。[方法]利用微卫星标记技术研究新疆地区无角陶塞特、萨福克与中国美利奴绵羊群体的遗传多态性,并对所列举微卫星位点的多态性进行统计分析。[结果]所测3个绵羊群体的基因频率分布不均匀,其有效等位基因数在12～15,不同等位基因间片段大小的差异不等。3个品种绵羊群体的变异程度很高,各绵羊品种的杂合度为0．8214-0．9252。所选4个微卫星座位均表现出了高度多态性,多态信息含量（PIC）为0．7923～0．9167,是普遍适合于绵羊肉用生产性状的多态标记。[结论]该研究为进一步寻找与生产性能相关的遗传标记提供了理论依据。