Population genetics of the group specific component (Gc) and phosphoglucomutase (PGM1) studied by isoelectric focusing

For the determination of the group-specific component (Gc) and phosphoglucomutase (PGM1) phenotypes, isoelectric focusing was performed on two samples, one of Jat Sikh of northwest India, the other of northeast English. The subtype frequencies of these two systems do not differentiate the two populations sampled. Synthesis of the existing data shows distinct PGM1 and Gc subtype frequencies in various ethnic and racial groups. The anthropological implication of these subtype frequencies is discussed.     

Orosomucoid (ORM1 and ORM2) types in the Spanish Basque Country, Galicia and northern Portugal

The genetic variation of orosomucoid (ORM1 and ORM2) in three south-western European populations (Galicia, Spanish Basque Country and northern Portugal) was investigated using hybrid isoelectric focusing. Three common ORM1 alleles were observed in these populations, the frequencies of ORM1 *S observed in Galicia and northern Portugal being the highest found among populations of European origin. Rare variants were observed for both the ORM1 and ORM2 loci.     

Population distribution in North and Central America of PGM1 and Gc subtypes as determined by isoelectric focusing (IEF)

Gc subtypes of 20 North and Central American populations and PCM₁ subtypes in 11 populations were analyzed to identify interpopulation variation of the respective gene frequencies for common alleles. A total of 23,304 phenotypings were done. Absolute heterozygosity levels (D) generally increased twofold when phenotyping by isoelectric focusing was compared with conventional electrophoresis. Graphic representation of the Gc subtypes and multivariate analysis to identify genetic affinities of the populations under study reveal genetic clusters consistent with major historical and geographical groupings of man.     

Study of transferrin (TF), group specific component (GC) and alpha-1-antitrypsin (PI) subtypes in the populations of Basque country (Spain)

Genetic polymorphisms of three serum proteins Transferrin (TF), Group Specific Component (GC), and Alpha-l-Antitrypsin were investigated by isoelectric focusing (IEF) in the Basque and non Basque populations from Vizcaya and Guipuzcoa, Spain. Two of the three genetic systems (TF and PI) showed conclusive genetic heterogeneity between the Basque populations of these two provinces. In addition to the past genetic drift, the present day genetic differentiation in the Basque country seems to be contributed by the unique structure of its populations.     

Protein subtype polymorphisms (Gc and Tf) in a Catalan population from Gerona (northeastern Spain)

The Tf and Gc polymorphic subtype variants have been examined by means of isoelectric focusing in a population sample from two subpyrenean regions in the province of Gerona (Northeast Spain). The estimated allele frequencies were Tf*C1 = 0.774, Tf*C2 = 0.167, TF*C3 = 0.055, TF*B = 0.004; Gc*1F = 0.129, Gc*1S = 0.555 and Gc*2 = 0.316. These values are in general similar to those so far reported in other Spanish populations. The comparisons between our data and those published in Spain, indicate that the present sample is closer to Barcelona than to the other groups compared.     

Human alpha 1-antitrypsin genetic polymorphism: PI N subtypes

Three new genetic variants (PI types) of alpha 1-antitrypsin are described. They have been compared to previously described phenotypes by several techniques including narrow pH range isoelectric focusing in ultrathin polyacrylamide gels. In this system, the relevant alpha 1-antitrypsin gel bands, identified by crossed immunoelectrophoresis, focused between PI M2, the most cathodal PI M subtype, and PI P BUD, the most anodal PI P subtype. They were therefore considered to be PI N subtypes. Two of them, PI N GRO and PI N YER, could not be separated by isoelectric focusing, but gave a different pattern in agarose gel electrophoresis. None of the new alleles seemed to be associated with disease. The high resolving power of isoelectric focusing is emphasized with respect to the information it may provide concerning amino acid substitutions, while the use of other techniques proved to be of utmost importance in the differentiation of other variants showing similar isoelectric points.     

A study of the genetic polymorphism of human inter-alpha-trypsin-inhibitor (ITI) in the Han population,Chengdu, China

Phenotypes of inter-alpha-trypsin-inhibitor (ITI) have been determined by isoelectric focusing on polyacrylamide gels followed by immunofixation. The phenotype frequencies of ITI in the Han population in Chengdu, P. R. China have been investigated using this method. In addition, family studies have been conducted in 21 families. The results show that ITI is polymorphic in the Han population in Chengdu, China. The allele frequencies are as follows: ITI*1 = 0.5763. ITI*2 = 0.4107, ITI*3 = 0.0130. ITI is thus a new and promising genetic marker that can be used in the field of forensic haematogenetics.     

Genetic studies of human apolipoproteins. XV. An overview of IEF immunoblotting methods to screen apolipoprotein polymorphisms

Genetically determined structural variation in the gene products of various apolipoproteins plays a significant role in modulating lipid levels in the population at large. However, due to tedious and cumbersome experimental problems involved, the detailed characterization of this genetic variation has been limited. The recent development of simple and sensitive isoelectric focusing and immunoblotting methods has circumvented these technically associated problems to a large extent, and this has allowed us to expand the genetic data on various apolipoproteins to previously uncharacterized populations. We have reviewed here these isoelectric focusing and immunoblotting methods. A comprehensive listing of allele frequencies has also been given for the polymorphic apolipoproteins.     

Gc subtypes in Finns, Swedes and Swedish Lapps

The group-specific component (Gc) subtypes were determined by isoelectric focusing and immunoblotting. The gene frequencies in the Swedish Lapps were Gc1F = 0.412, Gc1S = 0.367 and Gc2 = 0.221, which was significantly different from the frequencies found in Finns and in the populations of northern and central Sweden (p less than 0.001). The gene frequencies in the Swedish Lapps, although similar to those in Asiatic populations, are probably not reflecting an Asiatic influence, since the accumulated genetic information on the Swedish Lapps suggests that founder effect and genetic drift are to a large extent responsible for the peculiar gene pool of the original Lapp population.     

Genetic polymorphism of a haemoglobin chain and adenosine deaminase in European shads: evidence for the existence of two distinct genetic entities with natural hybridization

The degree of genetic differentiation between European shads, Alosa alosa and A. fallax , was studied in populations from different Portuguese hydrographic basins. Using isoelectric focusing, polymorphic variation was detected in a haemoglobin (HB) chain and in adenosine deaminase (ADA). These polymorphisms are shared by the two species but show significant differences in their gene frequency distributions. Individuals with intermediate morphological characteristics were found to exhibit intermediate allele frequencies. While not completely excluding introgression, our results strongly support the existence of two distinct species that can hybridize.     

Genetic similarity of polyploids: a new version of the computer program POPDIST (version 1.2.0) considers intraspecific genetic differentiation

For evolutionary studies of polyploid species estimates of the genetic identity between species with different degrees of ploidy are particularly required because gene counting in samples of polyploid individuals often cannot be done, e.g., in triploids the phenotype AB can be genotypically either ABB or AAB. We recently suggested a genetic distance measure that is based on phenotype counting and made available the computer program POPDIST. The program provides maximum-likelihood estimates of the genetic identities and distances between polyploid populations, but this approach is not informative for populations within species that only differ in their allele frequencies. We now close this gap by applying the frequencies of shared 'bands' in both populations to Nei's identity measure. Our simulation study demonstrates the close correlation between the band-sharing identity and the genetic identity calculated on the basis of gene frequencies for any degree of ploidy. The new extended version of POPDIST (version 1.2.0) provides the option of choosing either the maximum-likelihood estimator or the band-sharing measure.     

Observations on genetic diversity of Bulinus cernicus (Gastropoda: Planorbidae) from Mauritius

Enzyme variation has been investigated in eight populations of Bulinus cernicus from Mauritius using isoelectric focusing and starch gel electrophoresis. Of 11 loci examined for 10 enzyme systems, seven were found to be polymorphic. These were malate dehydrogenase, glucose phosphate isomerase, acid phosphatase (A and B), 3-hydroxybutyrate dehydrogenase, 6-phosphogluconate dehydrogenase and NADH-dependent diaphorase. Invariant loci were phosphoglucomutase, xanthine oxidase, fructokinase and αaL-glycerophosphate dehydrogenase. The percentage of polymorphic loci within the populations ranged from 9.1% to 54.5%. The average heterozygosity per population for all loci ranged from 0,009 to 0.203. Genetic distance values ranged from 0.01 to 0.3 with the higher values associated with comparisons of populations from the north-west and south-east of the island. A comparison of data sets for 1980 and 1986 revealed the allelic frequencies at five enzyme loci to be remarkably consistent.     

Ethnic variation in vitamin D-binding protein (GC): a review of isoelectric focusing studies in human populations

Summary Since the discovery in 1977 that the GC1 gene could be resolved into two common subcomponents on an isoelectric focusing (IEF) gel, a large number of ethnic groups have been screened to analyze the extent of genetic variation in human populations. Using the IEF technique, approximately 50,000 individuals from 160 different populations have been tested for the GC polymorphism. A marked variation in common GC suballele frequencies in different geographic areas seems to correlate with skin pigmentation and intensity of sun light. Pigmented (black) and keratinized (yellowish) skin type populations have a relatively high frequency of the GC ^*IF allele as compared to white skin populations. By comparison non-pigmented and non-keratinized white skin populations are generally characterized by having the maximum values of the GC ^*IS allele. The anthropologic significance of the GC locus has been enhanced further by detecting additional unique GC variants which provide useful information about evolutionary links between different populations. However, the presence of some electrophoretically identical unique variants in genetically and geographically distinct populations demand further investigation of these allelic variants to shed more light on their origins.     

Apolipoprotein H genetic variability in the population of Krk Island,Croatia

Apolipoprotein polymorphisms are emerging as suitable markers for the study of the formation of human populations. In contrast to the data available for apolipoprotein E, the data regarding apolipoprotein H (protein, apoH; gene, APOH) variations are only beginning to accumulate. By blood plasma isoelectric focusing and immunoblotting, we analyzed the distribution of apoH phenotypes in 397 individuals (192 males; 205 females) from seven villages of an autochthonous population of the eastern Adriatic island of Krk. APOH allele frequencies were: APOH*2 = 0.877, APOH*3 = 0.098, APOH*1 = 0.025, with the majority of the sample being homozygous. No significant differences between villages were observed. When these data were compared to those of other populations studied so far, a significant association between APOH allele frequencies and latitude was observed. We hypothesize that this association reflects differences in diet composition across different climatic zones.     

Microsatellite analysis of genetic diversity in wild and farmed Emus (Dromaius novaehollandiae)

The emu (Dromaius novaehollandiae) occupies most regions of the Australian continent and in recent times has been farmed for meat, oil, and leather. Very little is known about the genetic structure of natural or farmed populations of these birds. We report a preliminary study of genetic variation in emus undertaken by typing birds from five farms and two natural populations at five polymorphic microsatellite loci. Genetic diversity was high for all populations and there was little evidence of inbreeding, with most populations conforming to Hardy-Weinberg equilibrium for most loci. Significant heterozygote deficiencies at one locus in a number of populations were detected and may indicate the presence of null alleles. Comparisons of allele frequencies showed little evidence of genetic differentiation either among farmed populations or between farmed and natural populations.     

陕西实生板栗居群遗传多样性研究

利用超薄平板聚丙烯酰胺等电聚焦技术对陕西板栗4个实生居群,8个酶系统的20个位点进行了遗传多样性及遗传结构分析,结果表明：4个居群中以宝鸡居群遗传多样性最高,其P为80．0％,Ho,He分别为0．478和0．343,4个居群的居群遗传分化度Gst为6．2％,平均总遗传多样性为0．3372,总遗传多样性的93．8％属于居群内的遗传变异,聚类分析结果表明,以秦岭为界可以分为秦岭以南与秦岭以北2个略有差异的板栗自然亚分布区。     

Genetic polymorphism of group-specific component/vitamin-D-binding protein subtypes in six populations from north-eastern China

On six populations from North-Eastern China the frequencies of Gc subtypes were studied by isoelectric focusing on ultra-thin polyacrylamidegel followed by the improved sulfosalicylic acid precipitation. The following Gc subtype allele frequencies could be observed in the Han (Harbin), Ewenki, Tahur, Mongolian, Oroquen and Xibe populations: Gc*1F = 0.4246, 0.4941, 0.4479, 0.4077, 0.4606 and 0.4503; Gc*1S = 0.2587, 0.2936, 0.3151, 0.2822, 0.3370 and 0.3035; Gc*2 = 0.3065, 0.2064, 0.2266, 0.3006, 0.2022 and 0.2388. In addition to this 16 individuals of five populations showed rare Gc variant alleles (1A3, 1A8, 1A9, 1A14, 1C?).     

华木莲居群遗传结构与保护单元

华木莲(Sinomanglietia glauca)仅分布于江西宜春和湖南永顺, 是我国一级重点保护植物。前人采用RAPD、ISSR以及叶绿体SSCP(single-stranded conformation polymorphism)标记对华木莲进行了居群遗传学研究, 但未包括后发现的湖南居群或未检出居群内遗传变异。为了全面检测华木莲遗传多样性及其空间分布格局, 并据此确定保护单元, 本研究采用细胞核微卫星标记对华木莲所有4个居群共77个个体进行了居群遗传学分析。结果表明, 华木莲具有较低的遗传多样性(平均等位基因数A = 2.604, 平均期望杂合度H_E = 0.423)和较高的遗传分化(F_ST = 0.425)。STRUCTURE和主成分分析(Principal Coordinated Analysis, PCA)将4个居群首先分为江西、湖南两组, 江西的2个居群实际上是同一个自然繁育居群, 而湖南的2个居群则为2个分化明显的自然繁育居群。研究还发现湖南居群存在明显的杂合子过剩现象, 可能是小居群内随机因素造成的。研究结果表明华木莲可能在近期历史上遭受过强烈的瓶颈效应, 导致种群缩小、遗传多样性丧失和居群分化加剧, 需要加强对其进化潜力的保护。在制定保护措施时, 需要考虑其较高的遗传分化水平, 根据遗传结构可以将其划分为3个保护单元, 即湖南居群和江西居群分别为2个进化显著单元, 湖南居群进一步划分为2个管理单元(分别为朗溪乡云盘村和小溪乡鲁家村居群)。     

Microgeographic genetic structure in the yellow-pine chipmunk (Tamias amoenus)

While there is evidence for broad-scale genetic structure in small mammals, few studies have used variable DNA-based genetic markers to examine genetic differentiation at microgeographic (tens of kilometres) scales. Yellow-pine chipmunks (Tamias amoenus) live in the heterogeneous landscape of the Rockies in southwest Alberta and are generally restricted to areas of low elevation. We used seven microsatellite loci to determine whether chipmunks show evidence of population genetic structure among three closely situated sites (< 15 km) in the Kananaskis Valley, Alberta. We found evidence for genetic structure in the form of significant differences in allele frequencies among populations and significantly nonzero values of FST for both overall and pairwise population comparisons. However, FIS values for each population were not significantly different from zero, suggesting little evidence for inbreeding within populations. Genetic differentiation probably occurs as a result of the strong effect of drift in very small (N(e) approximately 25) populations of these animals even in the face of substantial immigration rates.     

中国汉族人群间-α-胰蛋白酶抑制因子(ITI)的遗传多态性

我们建立了测定间-α-胰蛋白酶抑制因子遗传表型的聚丙烯酰胺凝胶等电聚焦免疫固定技术,应用这种方法对居住在成都地区的汉族群体进行了群体研究和家系调查,结果表明中国汉族人群间-α-胰蛋白酶抑制因子具有遗传多态性,它有希望成为法医血液遗传学新的遗传标记。