短串联重复序列D7S2201基因座的群体遗传学研究

用扩增片段长度多态性技术分析短串联重复序列D7S2201基因座的遗传多态性,在262个中国成都地区汉族无关个体及119个泰国曼谷地区泰人无关个体中分别发现7个和5个等位基因,首次获得该基因座在两群体中的频率分布,其等位基因片段大小范围为100～124bp。两群体的基因型频率分布均符合Hardy Weinberg平衡。该基因座在两群体中的个人识别能力（PD）、杂合度（H）、多态性信息含量（CPI）及非父排除率（PE）分别为0.7038、0.5992、0.4789、0.2900和0.7351、0.5882、0.5012、0.2770。家系调查证实了等位基因的传递遵循孟德尔遗传规律。χ2检验表明两群体间等位基因频率分布无显著性差异。 Abstract：The polymorphism of a new short tandem repeat (STR) locus D7S2201 was analyzed by using AmpFLP. Seven alleles were observed in 262 unrelated Chinese individuals living in Chengdu and five alleles in 119 unrelated Thai individuals living in Bangkok, the ranges of fragment size were 100～124bp. The genotypes distributions of D7S2201 locus in the two populations were in accordance with Hardy Weinberg equilibrium. The discriminating power (PD), observed heterozygosity (H), polymorphism information content (CPI) and power of exclusion (PE) were 0.7038, 05992, 04789, 02900 in Chinese population and 0.7351, 0.5882, 0.5012, 0.2770 in Thai population respectively. Family studies confirmed Mendelian inheritance of alleles. No significant difference was observed between the two populations.     

北京地区汉族群体D1S1612和D18S535基因座的遗传多态性

采用扩增片段长度多态性（Amp-FLP）分型技术,调查中国北京地区汉族群体D1S1612、D18S535 基因座的遗传多态性,获得等位基因频率分布。结果显示, D1S1612检出9个等位基因,25种基因型, D18S535检出9个等位基因,27种基因型。两个STR基因座的杂和度（H）分别为0.779、0.887;个人识别率（Dp）分别为0.901、0.927;非父排除率（PE）分别为0.564、0.770;多态信息容量（PIC）分别为0.723、0.796,卡方检验表明两个STR 基因座基因型频率分布符合Hardy-Weinberg平衡 (P>0.01 )。D1S1612和D18S535 基因座均属高杂合度、高识别能力的遗传标记,可用于法庭科学亲子鉴定和个人识别。 Abstract: To investigate the genetic polymorphism of D1S1612 and D18S535 in Han population of Beijing. Amp-FLP method was used. 9 alleles, 25 genotypes were observed for D1S1612 locus; and 9 alleles and 27 genotypes for D18S535 locus. All allele frequencies, heterozygosity (H), discrimination power (Dp), exclusion of paternity probability (PE) and polymorphism information content (PIC) were calculated. The allele distributions of the two loci were conformed to Hardy-Weinberg equilibrium (P>0.01). According to the results obtained in this study, it is suggested that both D1S1612 and D18S535 are useful genetic markers for individual identification and paternity testing in forensic science practice as well for genetic study.     

云南汉族人群D17S30位点扩增片段长度多态性A

应用PCR技术和小型聚丙烯酰胺凝胶电泳银染法, 对云南汉族人群D17S30位点扩增片段长度多态性进行了分析。在被检的105名无关个体中,共检出12个等位基因,41种基因型。等位基因频率范围在0.0048-0.2190之间,杂合度为83.81%,DP值为0.9647。观察的基因型分布符合Hardy-Weinber g定律。 Abstract:A study on amplified fragment length polymorphism(Amp-FLP)at locus D17S30 in Han nationality of Yunnan was carried out by using PCR followed by a high-resolution PAGE technique and silver staining.In a sample of 105 unrelated individuals,a total 12 different alleles and 41 genotypes were detected.The heterozygosity was 83.81% and the probability of discrimination(DP) was 0.9647.The distribution of observed genotypes obeyed the Hardy-Weinberg equilibrium.     

云南汉族群体FIBRA、DHFRP2、ACTBP2基因座多态性及其法医学应用

采用Amp-FLP分型方法,调查云南汉族群体FIBRA、DHFRP2、ACTBP2基因座的遗传多态性,并将其应用于法医学实践。200份EDTA抗凝血采自昆明地区无血缘关系汉族个体,采用酚—氯仿法提取DNA;法医物证实际检案及亲子鉴定检材取自昆明医学院法医系物证教研室检案,各种动物血痕取自动物中心,采用酚—氯仿法或Chelex法提取DNA,PCR扩增,非变 性聚丙烯酰胺凝胶垂直板电泳,硝酸银染色分型。结果表明,FIBRA、DHFRP2、ACTBP2基因座分别观察到15、7、13个等位基因,基因型数分别是57、25、61。3个STR基因座的杂合度（H）分别为：0.8940、0.8174、0.9130;多态信息容量（PIC）分别是:0.8908、0.8045、0.9117;个人识别力（Dp）分别是：0.9733、0.9416、0.9772;非父排除率（Epp）分别是：0.7994、0.6542、0.8348,基因型频率分布均符合Hardy-Weinberg平衡。20个家系调查结果表明,3个基因组均符合孟德尔遗传规律。 Genetic Polymorphism of FIBRA,DHFRP2 and ACTBP2 and Their Forensic Application in Yunnan Han Population JING Qiang,NIE Sheng-jie Department of Forensic Medicine,Kunming Medical College,Yunnan Province 650031,China Abstract:To investigate the genetic polymorphism of FIBRA,DHFRP2 and ACTBP2 in Yunnan Han population as well as their application in forensic science,EDTA-blood specimens were collected from 200 healthy individuals.The DNA were extracted either by the Chloro form,phenol method or by the Chelex-100 method.The PCR products were analyzed by PAG vertical electrophoresis,following by silver staining.All gene frequencies,discrimination power (DP),exclusion of paternity probability (EPP),heterozygosity (H),polymorphisms information content (PIC),matching probability (PM) as well as the Hardy-Weinberg test were calculated.The obtained data are beneficial in the understanding of population genetics of the three STR loci in Yunnan Han population and the results suggest that these loci are valuable genetic markers for paternity testing and personal identification in forensic science practice. Key words：short tandem repeat; Amp-FLP; genetic polymorphism     

奶牛和肉牛6个STR基因座遗传多态性研究The Polymorphism Distributions of Six STR Loci in Dairy Cattle and Beef Cattle

利用PCR技术和复合电泳银染技术检测奶牛和肉牛BM2113、BM1862、BMc701、BM2934、TGLA122、BM720等6个STR基因座的多态性分布，并计算该6个基因座的基因频率（Pi）、个体鉴别力（DP）、杂合度（H）、多态信息含量（PIC）、和非父排除概率（PE）。结果显示：6个STR基因座的基因型分布符合Hardy-Weinberg平衡，奶牛中6个STR基因座中BM2113 基因座的DP、H和PIC最高，TGLA122基因座的PE最高。 6个STR基因座的累积个体鉴别力 （CDP）为 0.99997 ，累积非父排除能力（CPE）为 0.98827 。肉牛中6个STR基因座中BM1862 基因座的DP、H、PIC、PE都是最高，6个STR基因座的累积个体鉴别力（CDP）为 0.99999，累积非父排除能力（CPE）为 0.99578 。结果表明，6个STR基因座可用于牛的遗传连锁分析、个体识别和亲子鉴定等研究领域。Abstract：The polymorphism distributions of six STR loci，BM2113，BM1862，BMc701，BM2934，TGLA122，and BM720 were detected in cattle by Polymerase Chain Reaction and multiplex gel electrophoresis followed by silver staining. Gene frequency (Pi)，power of discrimination (DP), heterozygosity (H), polymorphism information content (PIC) and probability of paternity exclusion (PE) were calculated．All loci obey Hardy-Weinberg equilibrium. DP, H and PIC of BM2113 locus, and PE of TGLA122 locus are the biggest among six STR loci in Holstein Friesian. Cumulate DP of six STR loci is 0.99997, Cumulate PE of six STR loci is 0.98827. DP, H, PIC and PE of BM1862 loci are the biggest among six STR loci in beef. Cumulate DP of six STR loci is 0.99999, Cumulate PE of six STR loci is 0.99578. These results showed that the six STR loci could be used as linkage analysis, individual identification and paternity test in cattle.     

用多重PCR检测上海地区汉族人群9个STR基因座的多态性

利用多重PCR和四色荧光（5-FAM,JOE,NED和ROX）自动化检测技术调查上海地区汉族人群D3S1358、vWA、FGA、D8S1179、 D21S11、 D18S51、D5S818、D13S317、D7S820等9个STR基因座多态性分布并计算该9个基因座的基因频率（Pi）、个体鉴别力（DP）、无偏倚期望杂合性（H）、多态性信息含量（PIC）和非父排除概率（PE）。结果显示：9个STR基因座的基因型分布符合Hardy-Weinberg平衡,9个STR基因座中FGA基因座的DP值最高为0.9584,D8S1179的H值最高为0.9403,D18S51的PIC值最高为0.8560,D18S51的PE值最高为0.7391,9个STR基因座累积个体鉴别力(CDP)为0.9999996,累积非父排除能力(CPE)为0.99991。9个STR基因座适合作为中国人群的遗传标志,用于人类学、遗传疾病基因连锁分析、法医学亲子鉴定和个体识别等研究领域。 Abstract:By multiplex amplification and four fluorescent technique,the polymorphism distributions of nine STR loci,D3S1358,vWA,FGA,D8S1179,D21S11,D18S51,D5S818,D13S317 and D7S820 were investigated in Shanghai Han population.Gene frequency (Pi),power of discrimination (DP),polymorphism information content (PIC) expected heterozygosity (H) and probability of paternity exclusion (PE) were calculated.All loci meet Hardy-Weinberg equilibrium.DP of FGA locus,H of D8S1179 locus,PIC of D18S51 locus and PE of D18S51 locus are the biggest among nine STR loci.Cumulate DP (CDP) of nine STR loci is 0.9999996,Cumulate PE (CPE) of nine STR loci is 0.99991.Nine STR loci could be used as the genetic markers of Chinese population in the studies of anthropology,linkage analysis of genetic disease genes,individual identification and paternity test in forensic medicine.     

中国南方汉族群体MPSI型Kpn I酶切位点的遗传多态性

为研究中国汉族群体IDUA 基因Kpn I 酶切位点的遗传多态性以及该位点等位基因片段传递的规律, 采用PCR-RFLP技术, 对162例无血缘关系的健康中国汉人的324条 染色体进行检测,另又对5个家系16位成员进行同样的检测,然后用χ2检验进行统计学处理。结果表明,等位基因A1 频率为0.17,等位基因A2 频率为0.83,杂合率为29%;A1 、A2 的传递规律与理论上预计的完全符合。认为中国汉族群体IDUA 基因 Kpn I 酶切位点也具有遗传多态性, 并且与国外报道的无显著性差异;A1、A2 在世代中的传递完全符合孟德尔遗传规律。 Abstract:To investigate the genetic polymorphism of the Kpn I site in the α-L-iduronidase(IDUA) gene from a Han population in southern China and to study the mode of transmission of alleles, PCR-RFLP was used to analyze 324 chromosomes from 162 Chinese unrelated healthy Han individuals, and the analysis of the genotypes of 16 members in five families. To compare the frequencies and heterzygosity between Chinese Han population and Caucasians in Western by using χ2test. The frequency of allele 1 (450bp) was 0.17,allele 2 (390 plus 60 bp) 0.83, the heterozygosity was 29%.The genotypes of each member of all families detected was completely agreement with the theorical assessment. The locus of Kpn I in the IDUAgene from Han population has polymorphism. There is no significant difference between Chinese Han population and Caucasians in Western countries. The transmission of alleles was agreement with the Mendelian genetic law.     

Polymorphism profile of nine short tandem repeat Loci in the Han chinese

Nine short tandem repeat (STR) markers (D3S1358, VWA, FGA, THO1, TPOX, CSFIPO, D5S818, D13S317, and D7S820) and a sex-identification marker (Amel-ogenin locus) were amplified with multiplex PCR and were genotyped with a four-color fluorescence method in samples from 174 unrelated Han individuals in North China. The allele frequencies, genotype frequencies, heterozygosity, probability of discrimination powers, probability of paternity exclusion and Hardy-Weinberg equilibrium expectations were determined. The results demonstrated that the genotypes at all these STR loci in Han population conform to Hardy-Weinberg equilibrium expectations. The combined discrimination power (DP) was 1.05×10-10 within nine STR loci analyzed and the probability of paternity exclusion (EPP) was 0.9998. The results indicate that these nine STR loci and the Amelo-genin locus are useful markers for human identification, paternity and maternity testing and sex determination in forensic sciences.     

中国东乡族9个STR基因座遗传多态性研究

选择9个STR基因座,采用四色荧光标记STR基因扫描技术,对中国甘肃省特有民族——东乡族的群体遗传多态性进行研究。同时检测94个无关个体血液样本,共检出72种等位基因,基因频率的分布在0.0053~0.5825之间;检出182种基因型,基因型频率分布在0.0106~0.2660之间;9个STR位点基因型分布均符合Hardy-Weinberg平衡定律（P＞0.05）。9个STR位点多态信息量（polymorphism information content,PIC）均大于0.6378,杂合度(heterozygosity,H) 均大于0.6500,个体识别力(discrimination power,DP)均大于0.8216,非父排除率(probabilities of paternity exclusion,PPE) 均大于 0.4903。种族比较结果显示,甘肃东乡族与白种人及黑种人在绝大多数位点存在显著差异（P＜0.05）,而9个STR位点与汉族群体的遗传差异均不显著（P＞0.05）。研究结果丰富了中华民族基因数据库,在人类群体遗传学及法医学研究领域有重要应用价值。 Abstract:Genetic distribution for nine STR loci was determined in a Chinese Dongxing ethnic group based on STR genescan marked by fluorescence.Seventy-Two alleles and 182 genotypes were observed in 94 unrelated Chinese Dongxiang individuals,with the corresponding gene frequency and genotype frequency being 0.0053~0.5825 and 0.0106~0.2660 respectively.The genotypes of nine STR loci were in accordance with the Hardy-Weinberg equilibrium (P＞0.05).The statistical analysis of nine STR loci showed PIC( polymorphism information content,PIC)≥0.6378,H(heterozygosity,H) ≥0.6500,DP (discrimination power,DP) ≥0.8216,PPE(probabilities of paternity exculation,PPE) ≥0.4903.The result indicated that there was a significant difference between Dongxiang ethnic group and the white and the black.There was no significant difference in Han nationality.These result filled the Dongxiang ethnic group-a specific group of Chinese into the genetic database and played an important role in Chinese population genetic study and forensic medicine application.     

上海地区汉族人5-HT2a受体基因T102C多态性的基因频率分布

为了揭示中国汉族人5-HT2a受体基因T102C多态性基因频率的分布,我们随机抽取了226例汉族健康人作研究,用限制性片段长度多态性(RFLPs)技术测定研究对象的基因型和等位基因。结果发现汉族正常人5-HT2a受体基因T102C多态性基因型频率依次为:A1/A2=0.5044,A1/A1=0.2965,A2/A2 =0.1991,两种等位基因频率依次为:A1=0.5487,A2=0.4513,杂合度H=0.50 44、期望杂合度h=0.4953,多态信息量PIC=0.3726,表明T102C多态性具有合适信息,对疾病的关联研究,法医学鉴定有一定的价值。 Abstract:To investigate the distribution about genotype and allele frequencies of T102C polymorphism in the 5-HT2a receptor gene Chinese Han population,the genotypes and alleles of 226 healthy person were examined with Restriction Fragment Length Polymorphisms(RFLPs)technique.The genotype frequencies are as follows:A1/A2=0.5044,A1/A1=0.2965,A2/A2=0.1991,respectively,and the allele frequencies are as follows:A1=0.5487,A2=0.4513,respectively.The heterozygosity(H)is 0.5044,the expected heterozygosity(h)is 0.4953,and the Polymorphism Information Content(PIC)is 0.3726.Our findings suggest that the T102C polymorphism in 5-HT2a receptor gene may have suitable information to be used for association study or forensic identification.     

Development of 198 novel EST-derived microsatellites in Eucalyptus (Myrtaceae)

? Premise of the study: Expressed sequence tag (EST)-derived microsatellites were identified in Eucalyptus through screening the GenBank database. The loci were sequence-verified and explored for polymorphism among 20 genotypes. ? Methods and Results: In total, 198 novel microsatellites were developed from 8262 unigenes, with the identity of 73.6-100% to the original sequences and presence of the expected repeat motifs. One hundred and eighty-four markers proved to be polymorphic among 10 E. urophylla and 10 E. tereticornis genotypes, with the number of alleles per locus, observed heterozygosity, and polymorphic information content being 2-17 (mean: 7.11), 0-1.0 (mean: 0.4511), and 0.0940-0.9131 (mean: 0.6571), respectively. ? Conclusions: These markers will be useful for germplasm characterization, genome mapping, and gene tagging for economic traits in the two species examined and may have potential for genetic applications in Eucalyptus.     

Identification of a variable number tandem repeat region in the human T cell receptor alpha-delta (TCRAD) locus

A number of different polymorphisms have been observed in coding as well as in non-coding regions of T cell receptor (TCR) genes. We report the identification and characterization of a highly polymorphic locus in the 3′ noncoding region of the human T cell receptor α/δ (TCRAD) on chromosome 14. In 202 unrelated individuals, ten different alleles were distinguished by polymerase chain reaction (PCR) and a heterozygosity rate of 64% was calculated. Sequence analysis revealed that this polymorphic region consists of 10 bp imperfect repeat units and represents a variable number tandem repeat region (VNTR). Stable Mendelian inheritance of this novel polymorphic marker was proven in four families. The localization of this VNTR polymorphism in the TCRAD locus should make it a useful system for linkage analysis in immunological disorders with a known role of TCRAD. Received: 19 February 1996 / Revised: 27 March 1996     

Polymorphism of Microsatellite Markers in Papaya (<Emphasis Type="Italic">Carica papaya</Emphasis> L.)

A set of 81 new microsatellite markers for Carica papaya L. previously identified by data mining using freely available sequence information from Genbank were tested for polymorphism using 30 germplasm accessions from the Papaya Germplasm Bank (PGM) at Embrapa Mandioca e Fruticultura Tropical (CNPMF) and 18 landraces. The data were used to estimate pairwise genetic distances between the genotypes. A neighbor-joining based dendrogram was used to define clusters and infer possible genetic structuring of the collection. Most microsatellites were polymorphic (73%), with an observed number of alleles per locus ranging from one to eleven. The levels of observed and expected heterozygosity for 51 polymorphic loci varied from 0.00 to 0.85 and from 0.08 to 0.82, averaging 0.19 and 0.59, respectively. Forty-four percent of microsatellites showed polymorphism information content (PIC) higher than 0.50. The compound microsatellites seem to be more informative than dinucleotide and trinucleotide repeats in average alleles per locus and PIC. Among dinucleotides, AG/TC or GA/CT repeat motifs exhibited more informativeness than TA/AT, GT/CA and TG/AC repeat motifs. The neighbor-joining analysis based on shared allele distance could differentiate all the papaya accessions and landraces as well as differences in their genetic structure. This set of markers will be useful for examining parentage, inbreeding and population structure in papaya.     

Estimation of genotyping error rate from repeat genotyping,unintentional recaptures and known parent–offspring comparisons in 16 microsatellite loci for brown rockfish (Sebastes auriculatus)

Genotyping errors are present in almost all genetic data and can affect biological conclusions of a study, particularly for studies based on individual identification and parentage. Many statistical approaches can incorporate genotyping errors, but usually need accurate estimates of error rates. Here, we used a new microsatellite data set developed for brown rockfish (Sebastes auriculatus) to estimate genotyping error using three approaches: (i) repeat genotyping 5% of samples, (ii) comparing unintentionally recaptured individuals and (iii) Mendelian inheritance error checking for known parent–offspring pairs. In each data set, we quantified genotyping error rate per allele due to allele drop‐out and false alleles. Genotyping error rate per locus revealed an average overall genotyping error rate by direct count of 0.3%, 1.5% and 1.7% (0.002, 0.007 and 0.008 per allele error rate) from replicate genotypes, known parent–offspring pairs and unintentionally recaptured individuals, respectively. By direct‐count error estimates, the recapture and known parent–offspring data sets revealed an error rate four times greater than estimated using repeat genotypes. There was no evidence of correlation between error rates and locus variability for all three data sets, and errors appeared to occur randomly over loci in the repeat genotypes, but not in recaptures and parent–offspring comparisons. Furthermore, there was no correlation in locus‐specific error rates between any two of the three data sets. Our data suggest that repeat genotyping may underestimate true error rates and may not estimate locus‐specific error rates accurately. We therefore suggest using methods for error estimation that correspond to the overall aim of the study (e.g. known parent–offspring comparisons in parentage studies).     

Short tandem repeat polymorphism of the D2S1242 locus in a Japanese population

Allele frequencies and sequence characteristics of the D2S1242 short tandem repeat (STR) locus were studied in a Japanese population sample. A total of 10 D2S1242 alleles and 34 genotypes were identified in 273 unrelated Japanese individuals. The five most common alleles detected had frequencies of over 10%. No deviations from Hardy-Weinberg equilibrium were found when the expected allele values were compared with the observed values. Sequence analysis of each allele showed a tetranucleotide polymorphism. Alleles 9 to 14 had different sequence structures than alleles 15 to 19. Allele 18 had a different sequence in the Japanese sample compared to an Austrian sample. The power of discrimination was 0.95. The present results demonstrate that the D2S1242 STR locus is a useful genetic marker in the Japanese population.     

云南白族人群Y染色体DYF155S1基因座多态性研究

揭示云南白族136例无关男性个体Y染色体小卫星DYF155S1基因座多态性。用已建立的AmpFLP和MVRPCR方法分析DYF155S1基因座长度多态性、5′端多态性、3′端多态性。DYF155S1基因座具有高度多态性,基因多样性（h）达09996。研究表明将AmpFLP和荧光MVRPCR结合起来更能充分揭示DYF155S1基因座多态性,可为遗传学、人类学及法医学的研究提供有效的工具和基础资料。     

Identification of unique alleles and assessment of genetic diversity of rabi sorghum accessions using simple sequence repeat markers

Genetic diversity among 42 sorghum accessions representing landraces (19), advanced breeding lines (16), local cultivars (2) and release varieties (5) with 30 simple sequence repeat (SSR) markers revealed 7.6 mean number of alleles per locus showing 93.3% polymorphism and an average polymorphism information content of 0.78 which range from 0.22 (Xtxp12) and 0.91(Xtxp321). The average heterozygosity and effective number of alleles per locus were 0.8 and 6.65 respectively. Cluster analysis based on microsatellite allelic diversity clearly demarcated the accessions into ten clusters. A total of 24 unique alleles were obtained from seven SSR loci in 23 accessions in a size range of 110–380 bp; these unique alleles may serve as diagnostic tools for particular region of the genome of respective genotypes. Selected SSR markers from different linkage groups provided an accurate way of determining genetic diversity at the molecular level.     

Floral-color polymorphism in Ipomoea purpurea: biased inheritance of the dark allele is not a general explanation for its maintenance

A previous investigation reported the existence in a single population of the morning glory (Ipomoea purpurea) of non-Mendelian inheritance at the W locus influencing flower color. In addition, it was shown that the magnitude of biased inheritance in that population was sufficient to maintain a floral-color polymorphism at that locus at frequencies approximating those observed in natural populations. The current investigation was undertaken to determine whether this biased inheritance was characteristic of other I. purpurea populations, and thus whether it provides a general explanation for maintenance of the polymorphism. The current study found no evidence for biased inheritance in two additional polymorphic populations examined. Non-Mendelian inheritance thus seems unlikely to constitute a general explanation for the maintenance of this floral-color polymorphism in l. purpurea.     

用改进的MVR-PCR方法检测河北地区汉族人群D7S21基因座多态性

为研究D7S21基因座在河北汉族人群分布的多态性,应用MVR-PCR ( Minisatellite Variant Repeat-Polymerase Chain Reaction)方法和聚丙烯酰胺梯度凝胶电泳银染法对124名河北汉人无关个体D7S21基因座进行了快速检测,并进行数字编码。每一个体平均得到36个数字编码,未发现任何两个无关个体所有编码相同,两无关个体36个编码相同的概率为3.48×10-18。三种重复单位a型、t型和0型出现的概率分别为：48.5 ％、49.4％和 2.1％。该基因座杂合度为0.9876,非父排除率为0.9746,多态性信息含量为0.9872。研究表明,D7S21基因座在河北汉族人群中具有高度的多态性,聚丙烯酰胺梯度凝胶电泳银染法简便、快速,具有一定的实用价值。 Abstract:To study the polymorphism at D7S21 locus in Hebei Han population,124 unrelated individuals were detected rapidly by Minisatellite Variant Repeat-Polymerase Chain Reaction (MVR-PCR) and polyacrylamide gradient gel electrophoresis followed by silver staining,and digital codes were obtained.About 36 digital codes were obtained from each individual.No two unrelated individuals shared the same codes.The probability of identity in 36 digital codes was 3.48×10-18.The percentage of three repeat units,a-type,t-type and 0-type was 48.5%,49.4% and 2.1% respectively.The heterozygosity (H),excluding probability of paternity（EPP）and polymorphism information content（PIC）were 0.9876,0.9746and 0.9872 respectively.The results suggested that D7S21 locus has highly polymorphism in Hebei Han population.The method-polyacrylamide gradient gel electrophoresis followed by silver staining was simple,rapid and practical.