Andean potato varieties are cultivated in the northwest of Argentina and constitute the most important staple food for the
local farmers. The genetic diversity of 155 accessions conserved at the Genebank of Balcarce (INTA) was tested using four
microsatellites. Three commercial potato varieties of Tuberosum group and one accession of Curtilobum group were used as outgroups.
The presence of bands was scored for each microsatellite and for each accession and the data were analysed by principal coordinate
analysis. The polymorphism information content was obtained for each molecular marker from banding patterns. Analysis of molecular
variance was carried out with a variable number of accessions for each landrace, from different departments and sites within
departments. More than one genotype was detected in the majority of the potato landraces. Some accessions within each landrace
did not differentiate. AMOVA revealed that most of the genetic variation occurred among sites within departments and among
local varieties. These findings are discussed considering the agricultural practices carried out in the Andean farming system. 相似文献
Identification of collembolan species is generally based on specific morphological characters, such as chaetotaxy and pigmentation pattern. However, some specimens do not match to described characters because these refer to adult specimens, often of one specific sex, or the characters are highly variable in adults (e.g. pigmentation, setae or furcal teeth). Isozymes have frequently assisted species discrimination, and also these may vary with developmental stage or environmental conditions. For identification of single species of the Isotoma viridis group, we present both direct sequencing of the cytochrome oxidase subunit II (COII) gene and a simple DNA-based molecular method.
Five PCR primers amplifying the COII region (717 bp) of the mitochondrial DNA were used. The sequences clearly separated the species I. viridis, I. riparia and I. anglicana, irrespective of colour varieties within the first species. DNA amplification products of different species can also be distinguished by digestion with restriction endonucleases, followed by gel electrophoresis for separation of fragments. This restriction fragment length polymorphism (RFLP), obtained after digestion with the endonucleases TaqI, VspI, MvaI and Bsp143I, revealed specific fragments that separated the three species from each other. Since restriction enzymes are sensitive to single base mutations, we suggest to use a combination of enzymes with at least two species-specific restriction sites when using the RFLP technique. For the I. viridis complex, VspI and Bsp143I appear to be an appropriate combination. 相似文献
经Tris—HCl缓冲液(pH8.6)抽提,正丁醇脱脂,硫酸绥分级沉淀分离,DEAE—Sepharose Fast Flow和Sephacryl S-200柱层析,从黄鳝内脏中提取出电泳纯的碱性磷酸酶。用PCMB,NBS,PMSF,TNBS,SUAN,DTT及IAA在一定条件下选择性修饰该酶的各种氨基酸残基,并对酶活力的变化作出测定。结果表明,PMSF,NBS,TNBS,SUAN和DTT的修饰能显著抑制酶的活性,且酶活力降低程度与修饰别的浓度相关;IAA和PCMB的修饰不表现对酶的抑制作用。初步认为,Ser,Lys和Trp残基为黄鳝碱性磷酸酶的必需功能基团,部分二硫键对保护酶的催化能力是必需的。 相似文献