Large scale population structure and gene flow in the planktonic developing periwinkle, Littorina striata, in Macaronesia (Mollusca: Gastropoda)

Allozymes were used to investigate the genetic structure of 42 populations of the planktonic developing, Macaronesian periwinkle Littorina striata, throughout its entire geographic range (Azores, Madeira, Canary Islands and Cape Verde Islands). This periwinkle is presumed to have a high dispersal and gene flow potential, because it has a planktonic development. It is therefore expected to show little population genetic differentiation. Indeed, based on Wright's hierarchical F-statistics, no significant genetic differentiation could be detected among populations, at any of the specified hierarchical levels (i.e. population, island, and archipelago). Nevertheless, the Cape Verde Islands seemed genetically more diverse (highest mean number of alleles per locus). The number of loci revealing a significant genetic heterogeneity increased with increasing distance between populations, while private alleles based gene flow (Nm) estimates also revealed a tendency towards a geographical pattern. The distribution of rare and private alleles, might account for these observations which suggested some geographical effect. Because of the low frequency at which these alleles occur, their influence on the genetic population structure is negligible, and not picked up by F-statistics.     

Hordein locus polymorphism in near eastern local populations of cultivated barley (Hordeum vulgare L.)

Electrophoresis in starch gel has been used to study the polymorphism of hordeins encoded by loci Hrd A, Hrd B, and Hrd F in 140 local barley populations from the Near East, including 60, 34, 33, 8, and 5 populations from Syria, Jordan, Iraq, Palestine, and Israel, respectively. Fifty-seven Hrd A, 87 Hrd B, and 5 Hrd F alleles have been found. The alleles of these loci considerably differ in frequencies and distribution in populations from different Near Eastern countries. Cluster analysis of the matrix of the frequencies of hordein locus alleles in barley populations from the Near East, North Africa, Ethiopia, and South Arabia has yielded two clusters. The first cluster includes barley populations from Israel, Palestine, Morocco, Tunisia, Algeria, and Egypt; the second cluster, populations from Iraq, Syria, Jordan, Yemen, and Ethiopia.     

C8A and C8B polymorphisms in Norwegians and Norwegian lapps

C8 inheritance patterns in 364 mother-child pairs formed the basis for evaluation of the existence of silent alleles (null alleles) in the genes determining the two known polymorphic C8 systems. While evidence for such alleles was not found in C8A (alpha-gamma complex), two observations of null allele segregation in C8B (beta chain) indicate a C8BQ*0 allele frequency of about 0.07. Two population samples comprising 150 Lappish and 1,264 non-Lappish Norwegians were examined for phenotype distributions in C8A and C8B. The phenotype distributions were mainly in accordance with the expected Hardy-Weinberg distribution. The results for C8A indicated simple, codominant inheritance of two frequent and several rare alleles. Allele frequencies were similar in the two populations. The C8A B gene frequency in Norwegians was significantly lower than that in FRG and higher than that in Negroes. C8B allele frequencies were also calculated from gene counts in the population material, but with due corrections for the C8BQ*0 frequency observed in the mother-child material.     

Molecular and chromosomal polymorphism in continental and insular populations from the southwestern range of Drosophila subobscura

Eight insular and continental populations from the south-western range of Drosophila subobscura have been studied with regard to molecular and inversion polymorphisms. Heterogeneity between populations with respect to allele frequencies of 4 gene loci (Amy, Est-8, Est-9 and Pep-1) is the highest known for natural populations of the species. Moreover, the most common allele for these loci is not the same in all populations. Cladograms based on UPGMA clustering of the genetic distances based on allele frequency do not coincide with those constructed with inversion data. The allele-frequency differences between the populations may be due to non-random associations between enzyme alleles and gene arrangements and to founder effects appearing in the insular populations.     

Apolipoprotein E genotyping among the healthy Kuwaiti population

Apolipoproteins (lipid-free) are lipid-binding proteins that circulate in the plasma of human blood and are responsible for the clearance of lipoproteins. Apolipoprotein E (ApoE) is one of the several classes of this protein family. It acts as a ligand for the low-density lipid (LDL) receptors and is important for the clearance of very low-density lipid (VLDL) and chylomicron remnants. The APOE gene locus is polymorphic, with three major known alleles, APOE*3, *4, and *2. We investigated the distribution of the allele frequency of the APOE gene locus and describe here the genetic variation in four Kuwaiti subpopulations: Arab origin (Arabian peninsula), Arab Bedouin tribes, Iranian origin, and the heterogeneous population. We also describe the use of Spreadex gels in resolving the amplified and digested products of the APOE gene locus. DNA was extracted from whole blood and subjected to PCR and then to RFLP analysis. Allele and genotype frequencies were estimated for the total population and for each subpopulation. Statistical analysis showed no difference in the allele frequencies between the four groups. The frequency of APOE*3 in the Kuwaiti population was highest (88.4%) followed by the frequency of APOE*4 (6.5%) and APOE*2 (5.1%). The genotype and allele frequencies obtained for the Kuwaiti population fell within the reported worldwide distribution for the APOE gene locus. Moreover, the results obtained in this study showed no statistical difference (p > 0.05) between the APOE allele and genotype frequencies between the subgroups for all six genotypes and three alleles, supporting the assumption of admixture in the Kuwaiti population and that the obtained frequencies were in Hardy-Weinberg equilibrium. Finally, we found that the distribution of the APOE alleles in Kuwait differs somewhat from those reported in other Arab populations, suggesting that the Arabs originating from the Arabian peninsula are different from those of Lebanon, Morocco, and Sudan.     

Polymorphism of hordei-coding loci in Near Eastern local populations of cultivated barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

Electrophoresis in starch gel has been used to study the polymorphism of hordeins encoded by loci Hrd A, Hrd B, and Hrd F in 140 local barley populations from the Near East, including 60, 34, 33, 8, and 5 populations from Syria, Jordan, Iraq, Palestine, and Israel, respectively. Fifty-seven Hrd A, 87 Hrd B, and 5 Hrd F alleles have been found. The alleles of these loci considerably differ in frequencies and distribution in populations from different Near Eastern countries. Cluster analysis of the matrix of the frequencies of alleles of hordei-coding locus alleles in barley populations from the Near East, North Africa, Ethiopia, and South Arabia has yielded two clusters. The first cluster includes barley populations from Israel, Palestine, Morocco, Tunisia, Algeria, and Egypt; the second cluster, populations from Iraq, Syria, Jordan, Yemen, and Ethiopia.     

Analysis of polymorphism of CTG repetitive sequences in the gene of myotonic dystrophy in human populations of the Volga-Ural region]

Distribution of CTG repetitive sequences in the myotonic dystrophy (MD) gene was analyzed in ten populations of the Volga-Ural region, including Tatars, Chuvashes, Maris, Udmurts, Mordovians, Komis, and four ethnogeographical groups of Bashkirs. A total of 25 alleles were found (9 to 14 in individual populations), with each allele containing 5 to 34 trinucleotide repeats. The allele frequency distribution had two peaks corresponding to alleles with 5 and 11-14 CTG repeats. The frequency of the (CTG)5 allele varied from 0.23 to 0.47 in Maris and Mordovians, respectively. Regarding the (CTG)11-14 alleles, those containing 13 and 12 trinucleotides were most frequent in all populations; their frequencies varied from 0.15 in Mordovians to 0.24 in Maris and Bashkirs from the Abzelilovskii raion (district). Alleles with large numbers of repeats (more than 30) were only found in Tatars and Bashkirs from the Abzelilovskii raion, where their frequency was 0.01. The data obtained were compared with those on other human populations from various regions of the world. In general, the populations of the Volga-Ural region took an intermediate position between European and Asian populations (although were somewhat more similar to the latter ones) with respect to the distribution of allelic frequencies of the CTG repetitive sequences. In individual populations, the number of genotypes varied from 13 to 27 in Mordovians and Bashkirs from the Ilishevskii raion, respectively. The observed heterozygosity was the highest (91%) in Udmurts and the lowest (58%) in Mordovians; the average heterozygosity was 81%. Such a high heterozygosity, as well as the revealed differentiation of the populations with respect to the distribution of the allelic frequencies of CTG repetitive sequences in the MD gene, allow this polymorphic DNA locus to be considered a highly informative genetic marker of populations.     

Molecular variation at functional genes and the history of human populations--data on candidate genes for cardiovascular risk in the Mediterranean

A screening of 22 DNA polymorphisms has been performed in western Mediterranean populations (Iberian Peninsula, Morocco, and Central Mediterranean Islands). The analyzed markers correspond to polymorphic sites in several candidate genes for cardiovascular disease including apolipopoteins and their receptors (APOA1, APOB, APOE, APOC1, APOC2, LPA, and LDLR), genes implied in the hemostasis regulation (Factor VII, alpha and beta-fibrinogen, alpha and beta platelet-integrin, tissue plasminogen activator, and plasminogen activator inhibitor-1), and the angiotensin converting enzyme gene. The results are presented of a partial analysis carried out in following population samples: 6 from the Iberian Peninsula, 2 from Morocco, and 3 from Central Islands. The degree of inter-population diversity was significant and consistent with data from other kind of genetic polymorphisms. The apportionment of the allele frequency variance supported a geographic structure into three main regions: Central Mediterranean Islands, the Iberia Peninsula and North Africa. The genetic distance pattern is compatible with a south-to-north North African influence in the Iberian Peninsula and a remarkable gene flow from sub-Saharan Africa into Morocco. Epidemiologically, North Africa is characterized by high frequencies of LPA PNR alleles with high number of repeats (protective for cardiovascular risk) and high frequencies of the APOE*E4 allele (risk factor) as compared with European populations.     

Study of five haemogenetic markers (Gc, C3, Bf, Ag, and GALT) in six Indonesian populations and in 12 subgroups of Balinese

In various ethnic groups of the Indonesian archipelago and of Bali, the polymorphisms of the serum proteins Gc globulin (vitamin D-binding protein), C3 (complement component 3), Bf (complement factor B), Ag x,y (lipoprotein allotypes), and of the red cell enzyme system GALT (galactose-1P-uridyltransferase) were analysed. Among the studied proteins, the Gc system was the most informative one for the anthropologist. Besides considerable differences of frequencies of the common alleles Gc*1F, Gc*1S and Gc*2, a number of rare alleles (1A1, 1A3, 1A8, 1A9, 1A12, 1C2, 1C21, 1C24, and 2C8) and some new ones (1C28, 1C29, 1C30, 2C9) were observed. The presence of Gc*1A1 demonstrates the relationship to the Australo-Melanesian populations, but Mongolian variants (1A3, 1A8, 1A9, 1C2) were also encountered. Within the C3 system a very high frequency of the C3*S allele was observed in all populations. The rare alleles C3*F0.55, C3S1, and C3*S0.5 were observed in some groups. A new allele (C3*F0.35) was detected in a Chinese individual and in a nobleman from Bali. The frequency of the Bf*F allele was rather low in general, and the Bf*S0.7 allele was found in three Indonesian individuals only. The Ag*(x) frequencies were rather high, as it is known for Asiatic populations. Variability among subgroups was not very pronounced. The GALT*2 allele (Duarte variant of the enzyme) was observed very rarely; however, it was present in several populations. Enzyme activities could not be determined, and therefore we cannot tell whether the galactosaemia gene (GALT*0) was present or not.     

Cytochrome P4501A1 polymorphisms in the Amerindian and Mestizo populations of Mexico

Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We studied two CYP1A1 polymorphic sites (position 4889 and 6235) in a group of 212 unrelated healthy individuals belonging to three different Mexican populations (106 Mexican Mestizos, 52 Teenek and 54 Mayos). Comparison among Mexican populations showed increased frequency of the *Ile allele (A on position 4889) in Mexican Mestizos when compared to Amerindians (p < 0.05). The analysis of position 6235 showed increased frequencies of *m2 (C in this position) allele in Teenek when compared to Mestizos and Mayos (p < 0.05) and of *m2/*m2 genotype when compared to Mestizos (p < 0.05). Amerindian populations (from Mexico and South America) presented the lowest frequencies of *Ile (position 4889) and *m1 (position 6235) alleles, however these frequencies vary according to the ethnic group studied. Mexican Amerindian groups together with other South Amerindian populations showed the highest frequencies for *Val at position 4889 and the *m2 allele at position 6235. The present study corroborates the high frequencies of*Val and *m2 alleles in the Amerindian populations and detects some differences between Mexican populations that correlate with linguistic differences. Our data could be helpful in understanding the distribution of these polymorphisms and in clarifying their roles as genetic and evolution markers in Amerindian populations.     

Molecular polymorphism of O alleles in five populations of different ethnic origins

Sequences of exons 6 and 7 of the O allele of the ABO gene were studied in 317 individuals of the O phenotype from five different ethnic groups (Basques, Berbers, Akans from the Ivory Coast, and Amerindians: Cayapas from Ecuador and Aymaras from Bolivia). Twenty-one O alleles were characterized, among which 9 differed from all O alleles reported to date. The nine alleles differed from either the O01 allele (four out of nine) or O02 allele (five out of nine) by one to three point mutations. The number of different O alleles in population samples varied greatly: the highest number (13) was observed in Akans, and the lowest (5) in Amerindians. Some rare alleles previously reported by others at low frequencies were found with high frequencies in the Akans. The results also revealed a decreasing frequency of Ov7 alleles from south to north (Akans, Berbers, Basques). Berbers and Basques share two rare alleles, Ov6 and O03, which were not encountered in the other populations studied here.     

Allele frequencies of single nucleotide polymorphisms in the second exon of the myoglobin gene among the Japanese

The difference in the allele frequencies of two single nucleotide polymorphisms (SNPs) in the second exon of the myoglobin gene between Japanese and other populations is reported. These SNPs are the substitutions of (A79G) and (T109C), and they were investigated by a single polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis followed by direct sequencing. The substitutions were always linked and two alleles were found in the samples used: the A-T allele with no substitution at positions (79A) and (109T) and the G-C allele with substitutions of (79G) and (109C). The frequencies of these alleles were 0.755 and 0.245, respectively, and they were found to be in Hardy-Weinberg equilibrium. The distribution of alleles in the Japanese population was significantly different from that reported among whites, blacks, and Hispanics (p < 0.0001).     

Patterns of Gene Variation in Central and Marginal Populations of DROSOPHILA ROBUSTA

The central and marginal populations of D. robusta differ greatly in the level of inversion polymorphism; the marginal populations are monomorphic or nearly so and the central populations are highly polymorphic. This paper presents the frequencies of alleles at forty gene loci in various populations of D. robusta, studied by electrophoresis of proteins and enzymes. Population samples were obtained from eight widely separated populations of D. robusta which included the central, the extreme marginal and the intervening populations between the center and the margins. We find that the proportion of polymorphic loci and average heterozygosity per individual is slightly higher in the marginal populations than the central populations. In D. robusta on an average, 39% of the loci are polymorphic and the average proportion of loci heterozygous per individual is 11%. A breakdown of loci in three categories, viz, hydrolytic enzymes and some other enzymes, larval proteins and glycolytic and Kreb's cycle enzymes, shows that in all populations the level of polymorphism is highest in the hydrolytic enzymes, intermediate in larval proteins and least in the glycolytic and Kreb's cycle enzymes. On the average, the proportion of loci heterozygous per individual for three groups of loci is: hydrolytic enzymes and others (.164), larval proteins (.115) and glycolytic and Kreb's cycle enzymes (.037). We also observe that in all populations the level of polymorphism on the X chromosome is far less than the expected 38%; in salivary gland cells the euchromatic length of the X chromosome is 38% of the entire genome. Lower levels of polymorphism for the X chromosome loci are explained due to low probability of balanced polymorphisms for the X-linked loci since the conditions for establishment of balanced polymorphism for X-linked loci are more restrictive than for the autosomal loci.-The polymorphic loci can be grouped according to pattern of allele frequencies in different populations as follows: (1) The allele frequencies are similar in all populations at the XDH, Pep-1 and Hex-1 loci. (2) The alleles at the Est-1, Est-2, Amy loci and the AP-4(1.0) and the LAP-1(.90) alleles show north south clinal change in frequency. (3) There is north south and east west differentiation at the Pt-5, Pt-8 and Pt-9 loci and the allele AP-4(.81). (4) Polymorphism at loci such as Fum, B.Ox, Hex-8, Pep-2 and Pep-3 are restricted to only one or two of the populations. (5) Allele frequencies at the MDH and ODH loci fluctuate between populations. (6) Allele frequencies at many polymorphic loci such as Est-1, Est-2, LAP-1, AP-4, Pt-5, Pt-8, Pt-9, Pt-16, MDH, Fum change clinally within a gene arrangement. The pattern of gene variation in D. robusta is very complex and cannot be easily explained due to migration of neutral alleles between once-isolated populations or to semi-isolation of neutral alleles. The observations of the pattern of allele variation in different populations, high levels of polymorphism in the marginal populations which have small population size and low levels of polymorphism of the X chromosome loci all support the argument in favor of balancing selection as the main mechanism for the maintenance of these polymorphisms. Environmental factors must play a role in the maintenance of a great deal of these polymorphisms, since we observe clinal allele frequency changes even within a given inversion type.     

Population structure and conservation implications for the loggerhead sea turtle of the Cape Verde Islands

The Cape Verde Islands harbour the second largest nesting aggregation of the globally endangered loggerhead sea turtle in the Atlantic. To characterize the unknown genetic structure, connectivity, and demographic history of this population, we sequenced a segment of the mitochondrial (mt) DNA control region (380 bp, n = 186) and genotyped 12 microsatellite loci (n = 128) in females nesting at three islands of Cape Verde. No genetic differentiation in either haplotype or allele frequencies was found among the islands (mtDNA F _ST = 0.001, P > 0.02; nDNA F _ST = 0.001, P > 0.126). However, population pairwise comparisons of the mtDNA data revealed significant differences between Cape Verde and all previously sequenced Atlantic and Mediterranean rookeries (F _ST = 0.745; P < 0.000). Results of a mixed stock analysis of mtDNA data from 10 published oceanic feeding grounds showed that feeding grounds of the Madeira, Azores, and the Canary Islands, in the Atlantic Ocean, and Gimnesies, Pitiüses, and Andalusia, in the Mediterranean sea, are feeding grounds used by turtles born in Cape Verde, but that about 43% (±19%) of Cape Verde juveniles disperse to unknown areas. In a subset of samples (n = 145) we evaluated the utility of a longer segment (~760 bp) amplified by recently designed mtDNA control region primers for assessing the genetic structure of Atlantic loggerhead turtles. The analysis of the longer fragment revealed more variants overall than in the shorter segments. The genetic data presented here are likely to improve assignment and population genetic analyses, with significant conservation and research applications.     

CCR2-64Ⅰ在中国南方14个少数民族群体中的分布

为调查HIV-1感染相关等位基因CCR2-64Ⅰ在我国南方14个少数民族群体的频率和多态性分布, 从上述人群外周血中抽提基因组DNA, 采用PCR和PCR-RFLP等方法进行基因分型。在791例调查对象中, 636例是野生纯合子基因型, 104例为杂合子基因型, 51例为突变纯合子基因型。上述各群体等位基因型的分布符合Hardy-Weinberg平衡。14个民族群体的平均突变基因频率为13.6％, 等位基因频率范围分布在1.6％~30.3％之间, 14个民族群体之间突变基因频率具有显著差异(P<0.05)。广西壮族群体CCR2-64Ⅰ突变基因频率最低, 为1.6％, 云南的六库傈僳族频率最高, 为30.3％。12个群体的突变基因频率均低于中国汉族健康群体, 南方3个少数民族群体基因突变频率显著低于西南11个少数民族群体, 该突变基因在艾滋病发病过程中的影响值得进一步深入研究。     

Population database of STRs in West Africa: a genetic study of TPOX, HUMVWA31/A, HUMTH01, and CYP19

Four tetrameric STRs (TPOX, HUMVWA31/A, HUMTH01, and CYP19) were analysed in a West African population (Cabo Verde). No significant deviations from Hardy–Weinberg proportions were observed, either in conventional or exact tests. Pairwise comparisons confirmed allelic independence for all the combinations of loci. Data is provided for the first time about CYP19 in Black populations. In comparisons between African and Afro‐American populations, significant frequency differences for several alleles at the TH01 and VWA31/A loci were observed. The allele frequencies provided in this study contribute to a better knowledge of the variability of these markers among the main human groups, especially in the context of Subsaharan African populations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparative analysis of allele polymorphism of three short tandem repeats in the Russian, Uzbek and Georgian populations

The allele polymorphism of the AGC short tandem repeat (STR) of exon 1 of the androgen receptor (AR) gene located in Xq11-12, ATCT STR of intron 40 of the von Willebrand factor (vWF) gene located in chromosome 12p12, and AGAT STR of an anonymous DNA sequence (STRX1) from the short arm of the X chromosome was analyzed in the Georgian, Uzbek, and Russian populations. Polymerase chain reaction (PCR) with DNA of unrelated persons revealed 14 AR, 7 vWF, and 7 STRX1 alleles in Georgians; 14, 8, and 6 alleles, respectively, in Uzbeks; and 16, 8, and 9 alleles, respectively, in Russians. The heterozygosity at these STR was 0.61, 0.78, and 0.46 in Georgians; 0.60, 0.83, and 0.44 in Uzbeks; and 0.80, 0.70, and 0.58 in Russians. The correspondence of genotype frequencies to the Hardy-Weinberg equilibrium was observed with AR STR in Russians and Uzbeks, STRX1 STR in Georgians, and vWF in all three populations. A significant deviation from the equilibrium was found for STRX1 in Russians and Uzbeks and AR in Georgians. The potential of individualization was 0.05 for AR, 0.13 for vWF, and 0.18 for STRX1 in Georgians; 0.04, 0.09, and 0.13, respectively in Uzbeks; and 0.05, 0.14, and 0.07, respectively, in Russians. The allele and genotype frequency distributions of each STR were analyzed in all three populations. Allele frequencies in the populations were compared by the Kolmogorov-Smirnov test. The Russian population significantly differed in allele frequencies of the three STR from Uzbeks and in those of STRX1 and AR from Georgians. Georgians and Uzbeks significantly differed in vWF and STRX1 frequencies. The possibility of using the three STR in molecular diagnosis of the corresponding monogenic diseases, population genetic studies, and personal identification is discussed.     

Analysis of the CCR5 gene coding region diversity in five South American populations reveals two new non-synonymous alleles in Amerindians and high CCR5*D32 frequency in Euro-Brazilians

The CC chemokine receptor 5 (CCR5) molecule is an important co-receptor for HIV. The effect of the CCR5*D32 allele in susceptibility to HIV infection and AIDS disease is well known. Other alleles than CCR5*D32 have not been analysed before, neither in Amerindians nor in the majority of the populations all over the world. We investigated the distribution of the CCR5 coding region alleles in South Brazil and noticed a high CCR5*D32 frequency in the Euro-Brazilian population of the Paraná State (9.3%), which is the highest thus far reported for Latin America. The D32 frequency is even higher among the Euro-Brazilian Mennonites (14.2%). This allele is uncommon in Afro-Brazilians (2.0%), rare in the Guarani Amerindians (0.4%) and absent in the Kaingang Amerindians and the Oriental-Brazilians. R223Q is common in the Oriental-Brazilians (7.7%) and R60S in the Afro-Brazilians (5.0%). A29S and L55Q present an impaired response to β-chemokines and occurred in Afro- and Euro-Brazilians with cumulative frequencies of 4.4% and 2.7%, respectively. Two new non-synonymous alleles were found in Amerindians: C323F (g.3729G > T) in Guarani (1.4%) and Y68C (g.2964A > G) in Kaingang (10.3%). The functional characteristics of these alleles should be defined and considered in epidemiological investigations about HIV-1 infection and AIDS incidence in Amerindian populations.     

Four DNA polymorphisms on the short arm of the X chromosome: allele frequencies in a German and in a Turkish population

Four restriction fragment length polymorphisms, revealed by cloned arbitrary X chromosome segments (L1.28, RC8, pD2, 754) were studied in samples (50 individuals each) of a German and a Turkish population. All previously reported alleles of these polymorphisms were found in both populations, except the infrequent RC8 allele B3 (3.0 kb fragment), which was absent in both groups. The observed minor alleles were found to be rarer in the German series than in the Turkish group, but there was no conclusive evidence of essentially different allele frequencies in either population. However, the frequencies of the RC8 allele B2 (5.3 kb fragment) were differing at the 5% significance level. The allele frequencies of the four polymorphisms are presented and compared with those reported from other European regions.     

Analysis of Microsatellite DNA Polymorphisms in Rockfish Sebastes thompsoni and Application to Population Genetics Studies

Population differentiation and relationships among 6 natural rockfish populations collected from northern coastal seas around Japan were assayed using microsatellite DNA loci. Seven loci examined were polymorphic in all populations. The number of alleles per locus ranged from 6.7 to 9.3, and the average of observed and expected heterozygosity ranged from 0.63 to 0.68, and from 0.66 to 0.69, respectively. The observed genotype frequencies at each locus were almost in agreement with Hardy-Weinberg expectations with two exceptions (P < .05). The allele frequencies of 16 population pairs were significantly different (P < .05). Genetic distance (D _A ) between 6 populations ranged from 0.03 to 0.08. According to a neighbor-joining tree generated from the D _A values, the 6 populations fell into 3 clusters. These clusters were correlated with the geographical positions of each population; larval dispersions due to water current were also found to have an effect on these results. Received May 2, 2000; accepted July 17, 2000.