Enzyme polymorphism in placentae from northern Greece

Variations at the PGM1, GOTm, GOTs, and EsD loci were studied in placental samples from Northern Greece. The gene frequencies of GOTm and GOTs were found to be comparable with frequencies reported in other Caucasian populations. The frequencies of the EsD and PGMa11 alleles, however, were lower in Northern Greece than in other European populations.     

Genetic relationship among several pig populations in East Asia analysed by blood groups and serum protein polymorphisms

The gene frequencies were calculated to investigate genetic variation apparent in blood group and serum protein systems in Asian native pigs. The results revealed that gene frequencies were generally similar in the nine pig populations, except in some systems. Differences of gene frequencies were recognized in HpY and Cpc detected on Taoyuan pigs of Taiwan and Ohmini pigs of Japan, respectively. TfC and AmC alleles were found in eight pig populations except Ohmini pigs. The overall genetic distances were calculated by gene frequencies of 13 loci and it was observed that Taoyuan pigs are closer to Ohmini pigs than to Short-ear pigs of Taiwan and other East Asian native pigs. However, the genetic distances between Asian native pigs and European or American breeds were larger than those among East Asian native pig populations.     

Alpha-1-antitrypsin phenotypes in newborns from Central and Southern Italy.

The results of Pi typing on 500 infants from Central and Southern Italy are reported. Phenotype determinations were performed on umbilical cord serum. We observed nine different phenotypes; each of these is present in other European populations. The frequencies of the Pi alleles in our group were found to be, on the whole, comparable to those found in other populations widely separated geographically. However, the frequency of the Pi S gene in our sample (0.0670) was greater than that observed in Northern and Central European and American groups. Our Pi S frequency was similar to that found in a French group and lower than that of Spanish and Portuguese groups. Our data thus confirm the higher Pi S gene frequency in Latin populations.     

Genetic relationship among several pig populations in East Asia analysed by blood groups and serum protein polymorphisrns

The gene frequencies were calculated to investigate genetic variation apparent in blood group and serum protein systems in Asian native pigs. The results revealed that gene frequencies were generally similar in the nine pig populations, except in some systems. Differences of gene frequencies were recognized in Hp^Y and Cp^c detected on Taoyuan pigs of Taiwan and Ohmini pigs of Japan, respectively. Tf^C and Am^C alleles were found in eight pig populations except Ohmini pigs.
The overall genetic distances were calculated by gene frequencies of 13 loci and it was observed that Taoyuan pigs are closer to Ohmini pigs than to Short-ear pigs of Taiwan and other East Asian native pigs. However, the genetic distances between Asian native pigs and European or American breeds were larger than those among East Asian native pig populations.     

Studies of chromosome structure polymorphism in Asia Minor and Persian populations of Drosophila subobscura Coll

Summary By means of the male sample method samples of D. subobscura from the north and south coast of Asia Minor and from the south coast of the Caspian Sea were examined with regard to the gene arrangements contained in them. The samples were judged by the following three criteria: (1) the number of different gene arrangements present, (2) the frequencies in which these gene arrangements occur, and (3) the rate of zygotic combinations.The samples from Asia Minor were found to be highly polymorphic. In this respect, they are comparable with other samples from the northern border of the Mediterranean region.The Persian populations are poor as regards number of gene arrangements. Commonly, some gene arrangements are highly frequent and, accordingly, high rates of homozygous combinations dominate. Presumably, these are marginal populations.Comparisons between samples from the north and south coast of Asia Minor confirm the findings from other parts of the species' range. As a rule, the frequencies of various gene arrangements vary according to the latitude in which they occur. Since climate and vegetation are also largely correlated with latitude, it is assumed that this is due to adaptive reaction to ecological factors.Comparing populations from the Western and Eastern Mediterranean region, similar differences were recorded. Some gene arrangements seem to be confined to either the western or eastern part of the area, and other gene arrangements differ in frequency. Since the ecological conditions in these areas appear to be comparable, such differences might be due to the history of the formation and dispersal of gene arrangements.In general, the frequencies of the gene arrangements in the chromosomes A, U, E and O are most equal along the northern margin of the Mediterranean area and, correspondingly, the frequencies of the heterokaryotypes are highest. It may be assumed that many heterokaryotypes reach their highest degree of heterotic supremacy in this area, and/or that the different homokaryotypes are uniform with respect to adaptive values. The reasoning rests on the additional assumption that in this area the biological conditions are the least extreme, or, in other words, that D. subobscura is best adapted to this environment. As it is, the region appears to lie geographically near the center of the species' range. In the I-chromosome the most equal frequencies of gene arrangements along with the highest frequency of the heterokaryotypes are to be found in Central Europe.On the other hand, in various populations lying supposedly at the borders of the species' range, the frequencies of gene arrangements of at least some chromosomes are strongly unequal and, accordingly, the frequencies of the homokaryotypes are high.In populations where the polymorphism is high, the character of the polymorphism varies slightly from chromosome to chromosome. In the O-chromosome usually one gene arrangement is abundant, while a large number of others are rare; two gene arrangements tend to dominate in the I- and U-chromosome, whereas in the E-chromosome several gene arrangements are apt to share similar frequencies.     

Microsatellite analysis of the spectacled bear (Tremarctos ornatus) across its range distribution

DNA samples of the spectacled bear (Tremarctos ornatus) from five Andean countries, Venezuela, Colombia, Ecuador, Peru and Bolivia, were analyzed for nine microsatellite loci. Seven of them were polymorphic, which led us to investigate several population-genetic parameters. Private alleles and significant differences in gene frequencies were found among the populations studied, which demonstrated the extent of genetic differentiation among the spectacled bear populations. The levels of gene diversity measured with these microsatellites were rather modest in this species. Hardy-Weinberg disequilibrium was especially found for the overall and the Ecuadorian samples, and might be due to the Wahl-und effect or consanguinity. Significant genetic heterogeneity was mainly observed among the Colombian and the Ecuadorian populations. Markov chain Monte Carlo simulations clearly showed that two different gene pools were present, one present in the Venezuelan-Colombian bears and other in the Ecuadorian ones.     

Incidence of cleft chin among the Adi and Apatani of Arunachal Pradesh, Northeast India

The occurrence of cleft chin was studied among five endogamous groups (Padam, Minyong, Pasi, Gallong, Apatani) of Arunachal Pradesh, Northeast India. The incidence of this trait is low in all the groups. Thus, the populations are characterized by low frequencies of the gene Cl. Bisexual difference is significant only among the Minyong. While compared with other populations from Northeast India, the Mongoloid populations were found to be distinct from the only caste population, which has been investigated so far.     

Allozyme variation in stable flies (Diptera: Muscidae)

Polyacrylamide gel electrophoresis was used to resolve allozymes in the cosmopolitan blood-feeding stable fly,Stomoxys calcitrans (L.). Nineteen of 38 loci were polymorphic (53%). Mean heterozygosities among all loci and among only polymorphic loci were 0.096 and 0.182, respectively. These gene diversity measures are about half those among other muscid Diptera. Variation in gene frequencies was examined in 10 natural stable fly populations from Iowa and Minnesota. Gene frequencies were homogeneous at five of eight loci among six populations in 1990 and eight of eight loci among four populations in 1992. Wright'sF statistics showed no significant departure from random mating among stable flies. It was concluded that gene flow compensates for any local differentiation in stable fly populations.     

An analysis of the ABO gene frequencies in Turkey

Regional ABO gene frequencies were estimated. The heterogeneity in these frequencies among regions were analysed statistically. The populations of the southeast Anatolia and east Black Sea regions and of the eastern part of the Aegean region were found to be responsible for the heterogeneity among the regions of Turkey. The results were interpreted in relation to the history of Turkey.     

Molecular markers to study genetic drift and selection in wheat populations

Studying the heterogeneity in variation of gene frequency among populations or between generations may be a possible way to detect genomic regions experiencing selection. In order to evaluate this approach, RFLP markers were used to compare the allelic frequencies in wheat populations that had been submitted to natural selection. In 1984, samples of two composite cross populations were distributed in the French network for dynamic management of genetic resources. Since then, all the sub-populations have been cultivated in the same sites with no human selection. The strong differentiation between populations found for agro-morphological traits (earliness, resistance to pathogens, ...) provided evidence of their adaptation to local conditions. The two initial populations and six derived sub-populations cultivated for 10 years in four contrasted sites were studied with RFLP markers. Differentiation between sub-populations based on RFLP diversity was highly significant. Variations on allelic frequencies of the 30 loci scored were found to be much greater than expected under genetic drift only. This led us to conclude that selection greatly influenced the evolution of the populations. Some of the loci clearly presented a higher differentiation than the others. This might indicate that they were genetically linked to other loci polymorphic in the populations and involved in adaptation. However, the effect of one selected gene on a marker, even located very close to the gene, could not be predicted with certainty. Hence, though the populations were predominantly selfing, it seems that initial linkage disequilibriums between markers and selected genes were not strong enough to control closely the evolution of allelic frequencies at the markers.     

Apolipoprotein A1 gene polymorphisms at the -75 bp and +83/ 84 bp polymorphic sites in healthy Omanis compared with world populations

The relative frequencies of the *A allele of the APOA1 gene at -75 bp (M1-) and the C or T +83/+ 84 bp allele (M2-) varied significantly between populations. We found the frequencies of M1- and M2- to be 0.22 and 0.067, respectively, in 150 healthy Omanis. These frequencies were compared to frequencies found in other world populations.     

Population Genetics of Euphydryas Butterflies. I. Genetic Variation and the Neutrality Hypothesis

Twenty-one populations of the checkerspot butterfly, Euphydryas editha, and ten populations of Euphydryas chalcedona were sampled for genetic variation at eight polymorphic enzyme loci. Both species possessed loci that were highly variable from population to population and loci that were virtually identical across all populations sampled. Our data indicate that the neutrality hypothesis is untenable for the loci studied, and therefore selection is indicated as the major factor responsible for producing these patterns. Thorough ecological work allowed gene flow to be ruled out (in almost all instances) as a factor maintaining similar gene frequencies across populations. The Lewontin-Krakauer test indicated magnitudes of heterogeneity among standardized variances of gene frequencies inconsistent with the neutrality hypothesis. The question of whether or not to correct this statistic for sample size is discussed. Observed equitability of gene frequencies of multiple allelic loci was found to be greater than that predicted under the neutrality hypothesis. Genetic differentiation persisting through two generations was found between the one pair of populations known to exchange significant numbers of individuals per generation. Two matrices of genetic distance between populations, based on the eight loci sampled, were found to be significantly correlated with a matrix of environmental distance, based on measures of fourteen environmental parameters. Correlations between gene frequencies and environmental parameters, results of multiple regression analysis, and results of principle component analysis showed strong patterns of association and of "explained" variation. The correlation analyses suggest which factors might be further investigated as proximate selective agents.     

Allozyme diversity and genetic divergence of the dolly varden Salvelinus malma Walbaum from the Kuril islands

Genetic variation was studied in the southern subspecies of the Asian Dolly Varden Salvelinus malma krascheninnikovi from the Kuril Islands. Thirty-six genetic loci controlling 19 enzyme systems were analyzed in 13 Dolly Varden populations from the Shumshu, Paramushir, Onekotan, Rasshua, Simushir, Urup, Iturup, and Kunashir islands. In the studied populations, the proportion of polymorphic loci was 35 to 85% and the mean heterozygosity was 0.104 to 0.173; populations from the Kunashir Island were characterized by maximum heterozygosity. In the island populations examined, significant inter-population heterogeneity of allele frequencies was found for all studied population pairs. For the total population of all islands, the inter-population diversity (GST = 0.188) was comparable to this parameter for the total population from the Kunashir Island (GST = 0.170). Genetic distances between populations did not correlate with the corresponding geographical distances, which indicates the lack of a pronounced gene exchange between the island populations. Cluster analysis and multidimensional scaling based on genetic distances did not reveal clear groups among the studied populations but indicated greater similarity within the Iturup-Simushir-Urup-Paramushir group and a greater genetic divergence of the Kunashir, Onekotan, Rasshua, and especially Shumshu populations. In the Shumshu population, allele frequencies indicate the admixture of genes of the northern Dolly Varden. The observed pattern of genetic differentiation was probably caused largely by genetic drift under the conditions of a limited gene flow because of homing (which is typical of the Dolly Varden) and the presence of isolated nonanadromous populations. The population-genetic analysis of the Dolly Varden from the Kuril Islands does not give grounds to distinguish any other isolated Dolly Varden species in this region than S. malma, which is represented by the southern form S. m. krascheninnikovi with an admixture of the northern form S. m. malma in the Shumshu Island.     

Length variations in the COII-tRNA(Lys) intergenic region of mitochondrial DNA in Indonesian populations.

The prevalence of a 9-base-pair (bp) deletion between the mitochondrial cytochrome oxidase II (MTCOX*2) and lysine tRNA (MTTK) genes (region V) has been used to estimate the genetic relationships among Asian and Pacific populations. Many East Asian and Pacific Island populations have been examined previously, but the mitochondrial DNA (mtDNA) diversity of the intervening Indonesian archipelago has not previously been systematically examined. The 17,500 islands of Indonesia currently contain nearly 213 million people and extensive cultural, linguistic, and, presumably, genetic diversity. This study of 1091 individuals representing 15 ethnic groups is the most extensive mtDNA survey to date of the Indonesian archipelago. Six distinct length polymorphisms in region V were observed within these 15 populations. The 9-bp deletion was found in every population examined at frequencies comparable to those of previously examined East Asian populations and substantially lower than those in most Pacific Island populations. Despite the inclusion of Austronesian-speaking populations and a Papuan-speaking population, there was no statistically significant heterogeneity in the frequency of the 9-bp deletion among the 15 populations (p = 0.09). These data indicate that substantial gene flow occurred among the populations at some time in the past. Our observations of no significant correlations between genetic and geographic distances (r = -0.04, p = 0.53) coupled with the extensive cultural and linguistic differences currently within the archipelago suggest that little gene flow among neighboring populations has occurred recently.     

Gene polymorphism of the renin-angiotensin system in six ethnic/geographic regions of Belarus

The insertion/deletion polymorphism of the angiotensin-converting enzyme gene (ACE) and the T174M polymorphism of the angiotensinogen gene (AGT) have been studied in six ethnic/geographic regions of Belarus. Significant intrapopulation differences in ACE genotype frequencies have been found for the northern and eastern regions (the Dvina and Dnepr basins, respectively). Significant differences in the AGT genotype frequencies have been found between populations of the Dnepr basin and populations of all other Belarusian regions. The allele and genotype frequencies of the genes studied in the Belarusian population and populations of other regions of the world have been compared. The frequencies of the insertion (I) and deletion (D) alleles of the ACE gene in the Belarusian population are 50.7 and 49.3%, respectively, which is similar to these frequencies in European countries. The frequency of the M allele of the AGT gene in Belarus is 16.6%, which is higher than its frequency in populations of European, African, and Asian origins.     

Restriction fragment length polymorphisms of three collagen genes in Russians and Buryats.

The restriction fragment length polymorphisms (RFLPs) of 3 collagen genes have been studied in two USSR populations. Four high-frequency alleles, also reported in other populations, were observed. The frequencies of alleles for the polymorphic sites MspI and EcoRI of the COL1A2 gene, HindIII of the COL2A1 gene and EcoRI of the COL3A1 gene were found to be 0.836, 0.398, 0.447 and 0.786, respectively, in Russians from Moscow (Caucasians), and 0.883, 0.519, 0.648 and 0.809, respectively, in Buryats from the Baikal region (Mongoloids). The RFLPs showed a fair agreement with the Hardy-Weinberg equilibrium. The frequencies were compared with those of other populations.     

ACE and LRPAP1 insertion-deletion polymorphisms in a northern Ivory Coast population

The ACE and the LRPAP1 gene insertion-deletion polymorphisms were determined in 133 healthy individuals sampled from Ouangolodougou, a village located in northern Ivory Coast. No sex differences were found in ACE and LRPAP1 gene frequencies. The ACE insertion and deletion alleles had frequencies of 0.346 and 0.654, respectively. The ACE gene was not in Hardy-Weinberg equilibrium because of an excess of heterozygote genotypes and a deficiency of I/I genotypes compared to the expected values. Statistical analysis showed a significantly lower frequency of I/I genotypes in the Ivory Coast population compared to Sudan, Kenya, African Americans, and African Brazilians (p < 0.05), whereas no differences were found with respect to Somalia. Conversely, the frequencies of the insertion and deletion alleles in the Ivorian population did not differ from those of other African populations. The LRPAP1 insertion and deletion allele frequencies found in our study (0.192 and 0.808, respectively) did not differ significantly from the Czech and Spanish populations, the only two populations previously characterized for this polymorphism. However, the frequency of the I/I genotype was significantly lower than the frequencies observed in the European samples. Because of the limited information on the LRPAP1 gene polymorphism distribution in worldwide populations, it was not possible to draw any conclusion.     

Genetic differentiation of freshwater pond copepods at arctic sites

Freshwater pond copepod species at a low-arctic site show distributional and life history differences which may reflect different dispersal efficiencies. In order to ascertain levels of gene flow among populations, cellulose acetate gel electrophoresis was used to examine allozyme variation in Heterocope septentrionalis, Hesperodiaptomus victoriaensis and Leptodiaptomus tyrrelli near Churchill, Canada. Differentiation of gene frequencies among populations of these species, plus Hesperodiaptomus eiseni and Hesperodiaptomus arcticus at other sites along Hudson Bay was moderate. The variation in gene frequencies was less than that of other passively dispersing organisms from the same habitats, and only slightly greater than that reported for an intertidal copepod with pelagic larvae. The mean number of dispersers exchanged among populations per generation, estimated from Wright's island model, averages 4.1 for the three species. Dispersal efficiency, calculated using population size estimates, revealed differences among the three species. However, these differences were not consistent with that expected from their distributional patterns. This suggests that factors other than dispersal alone determine the distributions of copepod species.     

Non-equilibrium gene frequency divergence: persistent founder effects in natural populations

The estimation of gene flow using gene frequency divergence information has become increasingly popular because of the difficulty involved in the direct determination of gene flow among populations. The present study examined allozyme gene frequencies in populations of eighteen aquatic invertebrate taxa at two sites in northern Canada. Gene frequencies at polymorpic loci were significantly different among 8–31 localized populations of all species at Igloolik and among 10–36 populations at Churchill confirming the generality of gene pool fragmentation in pond-dwelling organisms. Measures of gene flow estimated from gene frequency divergence, which assume that gene frequency distributions are at equilibrium, were inconsistent with the probable dispersal capacities of taxa. This provoked an examination of historical events as alternative explanations. Both theory and computer simulations demonstrated that when populations grow rapidly in size after founding from few individuals, the gene frequency divergence established during colonization is resistant to decay by gene exchange. Our work suggests that gene frequency distributions are often not in equilibrium and that caution should be employed in attempts to infer gene flow from them in natural populations.