Collagen1α1 promoter drives the expression of Cre recombinase in osteoblasts of transgenic mice

Osteoblasts participate in bone formation, bone mineralization, osteoclast differentiation and many pathological processes. To study the function of genes in osteoblasts using Cre-LoxP system, we generated a mouse line expressing the Cre recombinase under the control of the rat Collagenlcd （Collα1） promoter （Collα1-Cre）. Two founders were identified by genomic PCR from 16 offsprings, and the integration efficiency is 12.5%. In order to determine the tissue distribution and the activity of Cre recombinase in the transgenic mice, the Coll αl-Cre transgenic mice were bred with the ROSA26 reporter strain and a mouse strain that carries Smad4 conditional alleles （Smad4^Co/Co）. Multiple tissue PCR of Collα1-Cre;Smad4^Co/＋ mice revealed the restricted Cre activity in bone tissues containing osteoblasts and tendon. LacZ staining in the Collα1-Cre;ROSA26 double transgenic mice revealed that the Cre recombinase began to express in the osteoblasts of calvaria at E14.5. Cre activity was observed in the osteoblasts and osteocytes of P10 double transgenic mice. All these data indicated that the Collα1-Cre transgenic mice could serve as a valuable tool for osteoblast lineage analysis and conditional gene knockout in osteoblasts.

Genetic Polymorphisms of 22 Novel Autosomal Short Tandem Repeat Loci in Sierra Leone Population

Background:Exploring and identifying novel alleles of noncombined DNAIndex System(CODIS)short tandem repeat(STR)loci in different ethnic groups is important for the establishment of forensic reference databases and study of population genetics.Aim:This study is aimed to explore the genetic polymorphism of 22 non-CODIS autosomal STR loci(D6S477,D18S535,D19S253,D15S659,D11S2368,D20S470,D1S1656,D22-GATA198B05,D8S1132,D4S2366,D21S1270,D13S325,D9S925,D3S3045,D14S608,D10S1435,D12S391,D7S3048,D17S1290,D5S2500,D2S1338,and D16S539)in Sierra Leone population and analyze the population genetic relationships in comparison with otherpopulations.Materialsand ethods:The amples of a total of 495 unrelated individuals(274 females and 221 males)from Sierra Leonewere examined by the Microreader^(TM)23SPID System,and their genetic polymorphisms and associated forensic parameters were calculated.The genetic relationships between Sierra Leonepopulation and other populations were evaluated as well.Results:Atotal of 287 alleles were observed with allelic frequencies ranging from 0.001 to 0.399.The cumulative power of discrimination(CPD)of the 22 autosomal STR loci was 0.99999999999999999999999999999538.The cumulative probability of exclusion(CPE)of the 22 autosomal STR loci was 0.9999998514(CPEdous)and 0.9999999999826(CPEtrios).All of the STR loci reached the Hardy–Weinberg equilibrium after Bonferroni correction.The population genetics analysis results demonstrated that Sierra Leone population exhibited distinctive genetic characteristics compared to those of East Asian populations and it had relatively close genetic distances to the Uygur population.Conclusion:The results of this study could enrich the forensic databases with Sierra Leone population.The 22 STR loci are highly polymorphic and could be used for forensic practice and population genetics studies.

Comparing the accuracy of Demirjian and Nolla methods and establishing a new method for dental age estimation in northeastern Chinese children

Dental age estimation plays an important role in the field of clinic medicine and forensic medicine.The Demirjian and Nolla methods are common scoring methods for dental age estimation but there was no research about the comparison of accuracy of these two methods in northeastern Chinese children.Hence,in this study,we compared the accuracy of these two methods to explore more suitable method for our studied population.We collected 535 orthopantomograms from northern Chinese children aged from 6 to 15 years and divided them into training dataset and testing dataset according to the ratio of 7:3.The dental age of training dataset were estimated using Demirjian and Nolla methods,respectively.The results suggested that the mean differences of these two methods were 0.24 and−0.40 years,and mean absolute difference were 0.65 and 0.59 years.Then to further improve the accuracy of dental age assessment,the new improved formulas and dental age conversion tables were established after analyzing the relationship between the sum scores based on Nolla method and chronology age in training dataset.According to the new method used in testing dataset,the minimum value of mean difference(0.00)and mean absolute difference(0.49)were obtained,which are largely smaller than that of Demirjian and Nolla methods.The new developed method and dental age conversion scales may be more suitable dental age estimation method for northeastern Chinese children.

Application of Cameriere’s method for dental age estimation in children in South China

The aim of this study was to evaluate the applicability of Cameriere’s European formula for age estimation in children in South China and to adapt the formula to establish a more suitable formula for these children.Moreover,the performance of dental age estimation based on Cameriere’s method combining the developmental information of permanent teeth(PT)and third molar(TM)was also analysed.Orthopantomographs of 720 healthy children in Group A,and orthopantomographs of 320 children and 280 subadults in Group B were assessed.The samples of Group A were divided into training dataset 1 and test dataset 1,and the samples of Group B were also divided into training dataset 2 and test dataset 2.A South China-specific formula was established based on the training dataset 1,and the comparison of accuracy between the Cameriere’s European formula and the South China-specific formula was conducted with the test dataset 1.Additionally,a PT regression model,a TM regression model,and a combined regression model(PTþTM)were established based on the training dataset 2,and the performance of these three models were validated on the test dataset 2.The Cameriere’s European formula underestimated chronological age with a mean difference(ME)of-0.47±1.11 years in males and-0.69±1.19 years in females.However,the South China-specific formula underestimated chronological age,with a mean difference(ME)of-0.02±0.71 years in males and-0.14±0.73 years in females.Compared with PT model and TM model,the PT and TM combined model obtained the smallest root mean square error(RMSE)of 1.29 years in males and 0.93 years in females.In conclusion,the South China-specific formula was more suitable for assessing the dental age of children in South China,and the PT and TM combined model can improve the accuracy of dental age estimation in children.

Genetic polymorphism of 29 STR loci in the Hunan Han population from China

Dear Editor,The Han population accounts for the majority of the Chinese population.Hunan is a large province located at 108
470–114
150 E and 30
080–24
380 N in Southern China,specifically in the area in the middle reaches of Yangtze River.The province has a total area of 218400 km2 and a population of 72 million.The Han population of the province is approximately 59.15 million[1].In this study,we evaluated the allele frequencies and forensic parameters of 29 short tandem repeat(STR)loci by using two commercial kits(GoldeneyeTM 20A kit and Investigator HDplex kit).