title: [Constructing standard allelic ladders for four short tandem repeat loci and employing them in a population study on Han Nationality of Chengdu in China].
abstract: OBJECTIVE
  To solve the problems in the accuracy and standardization of short tandem repeats-polymerase chain reaction (STR-PCR) typing, the authors adopted the molecular clone technology in producing the standard allelic ladders of D1S1676, D2S2735, D11S1977 and D22S444 loci and applied them in a population study on the Hans in Chengdu, China.
  
  
  METHODS
  PCR was used to produce several different allelic fragments of these loci. PCR products were eluted from the gel and re-amplified by PCR. The purified allelic fragments were then blunt-end subcloned individually into the pGEMR-T plasmid vectors and the recombinant were transfected into competent E.coli DH5alpha TM cells. The results of sequencing confirmed that the size and the construction of the inserts were correct. The recombinant plasmids DNA with the inserts were then used as template for re-amplification to generate the four loci standard ladders.
  
  
  RESULTS
  The authors succeeded in producing large quantity of standard allelic ladder of these four loci, with which the genetic polymorphisms of these loci in Chengdu Han population of China were studied.
  
  
  CONCLUSIONS
  This method is of high value for forensic DNA typing to construct standard ladders. D1S1676, D2S2735 loci are robust for forensic analysis in Chinese Han population, whereas the value of D11S1977 and D22S444 loci is limited.
authors.affiliation: Institute of Forensic Medicine, Sichuan University, Chengdu, Sichuan, 610041 PR China.
authors.forename: Jian-qiang
authors.initials: JQ
authors.lastname: Deng
authors.forename: Bing-wu
authors.initials: BW
authors.lastname: Ying
authors.forename: Mei-sen
authors.initials: MS
authors.lastname: Shi
authors.forename: Jing
authors.initials: J
authors.lastname: Yan
authors.forename: Zheng-jun
authors.initials: ZJ
authors.lastname: Jia
authors.forename: Ying-bi
authors.initials: YB
authors.lastname: Li
authors.forename: Jin
authors.initials: J
authors.lastname: Wu
authors.forename: Ji
authors.initials: J
authors.lastname: Zhang
authors.forename: Yi-ping
authors.initials: YP
authors.lastname: Hou
mesh_terms: D000483:Alleles; D044466:Asian People / Q000235:genetics; D002681:China; D005828:Genetics, Population / Q000379:methods; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic