Integration of the cytogenetic and physical maps of chicken chromosome 17

The chicken genome, like those of most avian species, contains numerous microchromosomes that cannot be distinguished by size alone. Unique properties attributed to the microchromosomes include high GC content and gene density, and an enhanced recombination rate. Previously, microchromosome GGA 17 was shown to align with the consensus genetic linkage group E41W17, and bacterial artificial chromosome (BAC) clones containing E41W17 markers were isolated and assigned on the physical BAC map as well as the recently assembled draft chicken genome sequence. For this study, these same BACS were utilized as probes for fluorescence in-situ hybridization (FISH) to develop the GGA 17 cytogenetic map. Here we detail the chromosome order of ten BAC DNAs, thereby deriving a cytogenetic map of GGA 17 that is simultaneously integrated with both the linkage map and genome sequence. The location of the FISH probes together with the morphological appearance of the chromosome suggested that GGA 17 is an acrocentric chromosome whose cytogenetic map orientation is reversed from that currently indicated by the linkage map and draft genome sequence. The reversed orientation and the centromere location of GGA 17 were confirmed experimentally by dual-colour FISH hybridization using terminal BACs and the centromere-specific CNM oligonucleotide as probes. An advantage of this cyto-genomic approach is the improved alignment of the sequence and linkage maps with cytogenetic features such as the centromere, telomeres, p and q arms, and staining patterns indicating GC versus AT content.     

Polymorphisms of tumor necrosis factor receptor 2 are not associated with insulin-dependent diabetes mellitus or Graves' disease

Insulin-dependent diabetes mellitus (IDDM) and Graves' disease (GD) are autoimmune endocrinopathies and associated with distinct HLA-DR and -DQ alleles as well as several tumor necrosis factor a (TNF-α) and β (TNF-β) alleles. TNF-α and TNF-β interact with TNF receptor (TNF-R), of which two subtypes have been described: TNF-R1 and TNF-R2. We investigated TNF-R2 alleles in 90 patients with IDDM, 101 with GD and 70 healthy controls. Genomic DNA was amplified with specific flanking primers for the untranslated 3 region of TNF-R2. SSCP analysis revealed two alleles by different fragment patterns: TNF-R2*1 and TNF-R2*2. Patients with IDDM or Graves' disease and controls did not differ significantly: TNF-R2*1/*1:IDDM(8%)/GD(2%)/KO(4%); TNF-R2*2/*2:IDDM(34%)/GD(48%)/KO(42%), heterozygosity TNF-R2*1/*2:IDDM(58%)/GD(50%)/KO(54%) (IDDM vs KO: P =0.46, χ²=1.57; GD vs KO: P =0.59, χ²=1.05). In conclusion, the studied polymorphism of TNF-R2 was associated with neither IDDM nor GD in a German population.     

Mutation analysis of NR0B2 among 1545 Danish men identifies a novel c.278G>A (p.G93D) variant with reduced functional activity

Variations of the small heterodimer partner (SHP, NR0B2) gene, an atypical nuclear receptor that inhibits transactivation by hepatocyte nuclear factor (HNF)-4alpha, are associated with obesity among Japanese. The purpose of the study was to evaluate the prevalence of SHP variants among obese Danish men. Using combined SSCP and heteroduplex analysis, we analyzed the entire coding region of SHP for variants in a cohort of 750 Danish men with early-onset obesity and genotyped a cohort of 795 nonobese control subjects using PCR-RFLP. Functional analyses of the identified coding region variants were performed in both MIN6-m9 and HepG2 cell lines. A total of five novel variants, including three missense variants (c.100C>G [p.R34G], c.278G>A [p.G93D], and c.415C>A [p.P139H]) and two silent variants (c.65C>T [p.Y22Y] and c.339G>A [p.P113P]) were identified. Moreover, the previously reported c.512G>C [p.G171A] polymorphism was identified. The 171A allele was not associated with obesity (p = 0.07). The 34G, 93D, and 139H-alleles were rare variants, which were found only among obese subjects. Among the four coding region variants, the 93D-allele showed a reduced in vitro inhibition of the HNF-4alpha transactivation of the HNF-1alpha promoter expression when expressed in MIN6-m9 and HepG2 cell lines (p<0.01). In contrast to reported findings among obese Japanese, functional variants are rare among Danish men. A functional 93D variant of SHP was identified in 1 out of 750 obese and in none of 795 nonobese control subjects. Further large-scale population studies are necessary to assess the clinical impact of this rare variant on obesity risk among European subjects.     

Genetic screen for mutations affecting development and function of the enteric nervous system.

An intact enteric nervous system is required for normal gastrointestinal tract function. Several human conditions result from decreased innervation by enteric neurons; however, the genetic basis of enteric nervous system development and function is incompletely understood. In an effort to increase our understanding of the mechanisms underlying enteric nervous system development, we screened mutagenized zebrafish for changes in the number or distribution of enteric neurons. We also established a motility assay and rescreened mutants to learn whether enteric neuron number is correlated with gastrointestinal motility in zebrafish. We describe mutations isolated in our screen that affect enteric neurons specifically, as well as mutations that affect other neural crest derivatives or have pleiotropic effects. We show a correlation between the severity of enteric neuron loss and gastrointestinal motility defects. This screen provides biological tools that serve as the basis for future mechanistic studies.     

白细胞介素-1基因多态性与高血压易感性的研究

目的　观察白细胞介素 - 1(interleukin- 1,IL- 1)基因多态性在中国汉族人群中的分布及其与原发性高血压 (essential hypertension,EH)的关系 ,初步分析其基因型与 EH易感性的相关性。方法　应用聚合酶链反应和限制性片段长度多态性的方法 ,检测湖北省汉族 15 2例 EH患者和 16 8名正常对照者的IL- 1基因多态性 ,包括 IL- 1α(- 889C/ T)位点、IL- 1β(- 5 11C/ T)位点、IL- 1β( 395 3C/ T)位点、IL- 1Ra( 80 0 6 T/ C)位点多态性以及 IL- 1Ra第 2内含子可变数串联重复序列多态性。结果　IL- 1α(- 889C/ T)位点、IL- 1β( 395 3C/ T)位点、IL- 1Ra( 80 0 6 T/ C)位点多态性和 IL- 1Ra可变重复序列多态性在 EH组和正常人群中的分布差异无显著性 (P>0 .0 5 ) ,而 IL- 1β(- 5 11C/ T)位点多态性在两组人群中的分布差异存在显著性 (P<0 .0 5 ) ,携带 CT基因型罹患 EH的危险性可增加 2 .5 4倍。结论　 IL- 1β基因启动子区 - 5 11位点 C/ T多态性可能与 EH易感性存在相关关系。     

华北地区汉族群体15个短串联重复序列基因座遗传多态性分析

目的调查华北地区汉族人群15个短串联重复序列(shorttandemrepeat,STR)基因座遗传多态性分布和群体遗传学数据。方法应用毛细管电泳技术和五色荧光复合扩增的方法,检测597名汉族无关个体的15个STR基因座基因型。结果15个STR基因座的基因频率分布均符合Hardy-Weinberg平衡,所检测的15个STR遗传标记均具有高度多态性,杂合度均超过0.62,15个基因座的个体识别力在0.802~0.967之间,非父排除率在0.320~0·697之间,匹配概率在0.033~0.198之间。15个基因座的累积个体识别能力为0.999999以上,累积非父排除率为0.99999571,累积匹配概率为8.93×10-18。结论联合检测15个基因座可为亲缘鉴定和个体识别提供可靠的法医学证据,这15个STR基因座适用于中国人群的法医物证学检验。     

Knowledge and attitudes towards preimplantation genetic diagnosis in Germany

BACKGROUND: Preimplantation genetic diagnosis (PGD) is a technique which is often related to emotional debates because of its ethical and social implications. Worldwide there are different forms of legislation; Germany constitutes an interesting case because of the historical background concerning eugenics and dealing with handicapped persons at the time of national socialism. PGD is currently not legal but there are still polarized positions and legalization remains an issue. Studies about the attitudes of the general population towards PGD are rare. METHODS: Data were collected in a representative survey carried out in November 2003. Subjects were 2110 persons in Germany aged 18-50 years. RESULTS AND CONCLUSIONS: Respondents had little knowledge about PGD. There were incorrect assumptions about the diagnostic possibilities and a lack of basic genetic knowledge. A tendency towards a general acceptance of PGD for medical indications was found. Non-medical indications such as sex selection were generally not accepted. It could be observed that respondents who already had a notion about PGD overestimated the diagnostic possibilities and would eventually use PGD in the future more than respondents who had never heard about PGD before.     

GM and KM allotypes in eight tribal populations of madyha Pradesh and Orissa, India

Summary Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n=731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21,26), and KM (1). In seven of these populations five different GM haplotypes were found:GM*1,17;21,26; GM*1,17;10,11,13,15,16; GM*1,2,17;21,26; GM*1,3;5,10,11,13,14,26; andGM*3;5,10,11,13,14,26. In the Kisan sample the haplotypeGM*1,2,17; 21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.     

三个常染色体隐性遗传早发型帕金森病家系的PARKIN基因研究

目的 探讨PARKIN基因与中国人常染色体隐性遗传早发型帕金森病（autosomal recessive early-onset Parkinson’s disease，AREP）家系的关系。方法 对3个AREP家系的6例患者和23位成员进行系统的临床检查并进行PARKIN基因PCR扩增，产物通过变性高压液相色谱（denaturing high—performance liquid chmnatogmphy，DHPLC）进行突变检测，阳性结果标本进行基因测序。结果 所有研究对象的PARKIN基因外显子均扩增成功。DHPLC检测和基因测序发现一个家系中存在PARKIN基因杂合Gly284Arg突变，另一个家系中存在PARKIN基因Ser167Asn多态性，且患者均有环境毒物接触史。结论 PARKIN基因杂合Gly284Arg突变在环境因素的协同作用下可能导致发病。PARKIN基因Ser167Asn多态性是帕金森病的易感因素，汞中毒与其共同作用可能导致发病。