Genetic variation at enzyme loci in North Atlantic minke whales,Balaenoptera acutorostrata

Electrophoretic variation within and between North Atlantic minke whale samples(Balaenoptera acutorostrata) from West Greenland, Iceland, and Norway was investigated. In the West Greenland samples, 28 enzyme systems were examined, representing 36 loci, of which 6 were found to be polymorphic. In Icelandic and Norwegian samples, 22 enzyme systems were examined, representing 29 loci, of which 6 and 5 were found to be polymorphic, respectively. The average heterozygosity was 0.058 (SE=0.024) in samples from West Greenland, 0.074 (SE=0.028) in samples from Iceland, and 0.054 (SE=0.023) in samples from Norway. No significant deviations from the expected Hardy—Weinberg genotypic frequencies, within samples taken from the same area, were found. Significant differences in allele frequencies were observed, however, between samples from the three different areas. The average Nei's genetic distance was 0.014 and the averageF _st value was 0.126. The genetic differences between the samples from the different areas indicate that those from West Greenland, Iceland, and Norway represented different breeding populations.     

Genetic comparison of salmon from the White Sea and north-western Atlantic Ocean

Samples of salmon Salmo salar from the River Kachkovka and the River Nilma in northern Russia were analysed by starch gel electrophoresis and compared to three Norwegian stocks, the Neiden river in northern Norway and Øyreselv and Hopselv rivers on the west coast. The comparison included the following polymorphic loci: AAT-4 *, IDDH-2 *, IDHP-3 *, MDH- 3,4 *, MEP-2 *, ESTD * as well as the newly discovered polymorphic loci FBALD-3 * and TPI-3 *. Samples were run side by side on gels, and the alleles found in the Russian stocks were the same as those found in the Norwegian stocks, although the electrophoretic methods used lead to differences in designations of alleles. A polymorphism in ESTD * which involves a slow allele was commonly observed in the three northern populations of the Nilma, Kachkovka and Neiden rivers. This allele was absent in the other Norwegian stocks and in a major brood stock of farmed salmon in Norway. The IDHP-3 * 116 allele was found in unusually high frequencies in the northern populations. Thus, the variability observed at these two loci indicates a barrier to gene flow between the northern salmon stocks and the more southern stocks in the East Atlantic area.     

A review of the genetic relationships of Atlantic walrus (Odobenus rosmarus rosmarus) east and west of Greenland

Studies of the genetic variation involving allozymes, mitochondrial and nuclear DNA (microsatellites) in walruses (Odobenus rosmarus) were reviewed. In addition, the genetic relationships of a total of 211 Atlantic walruses, O. r. rosmarus, from 5 sampling areas west and east of Greenland were studied using 12 nuclear DNA-microsatellite loci and restriction fragment length polymorphism obtained from the ND1, ND2 and ND3/4 segments of the mitochondrial DNA (mtDNA). At the mtDNA level, no divergence was observed among the three sampling areas east of Greenland (i.e. East Greenland, Svalbard and Franz Josef Land), whereas areas west of Greenland (i.e. Northwest and West Greenland) showed some differentiation. The genetic variation at the microsatellite loci grouped the individuals into four sub-populations: Northwest Greenland, West Greenland, East Greenland and a common Svalbard-Franz Josef Land sub-population. A significant correlation between genetic distance and geographic distance between the sampling areas (isolation-by-distance effect) was detected, especially at the mtDNA level. At a small-scale phylo-geographical level, the mtDNA data indicated that Atlantic walruses have diverged into two major groups: one northwest (i.e. in the North Water) and one east of Greenland (i.e. an East Greenland-Svalbard-Franz Josef Land group), whereas the haplotype distribution in the West Greenland sample reflected a mixture of both these groups. The microsatellite data supported a general grouping of walruses to the west and east of Greenland.     

中华稻蝗三种群遗传结构分析

应用淀粉凝胶电泳对山西省太原黄陵村、临猗县赵村及永济县伍姓湖3个中华稻稻（Oxya chinensis）种群的4个等位酶位点（MDH-1、MDH-2、LDH、ME）进行了分析。结果表明3个种群的中华稻蝗在遗传结构上具有差异;黄陵种群的MDH-1、MDH-2以及伍姓湖种群的MDH-1均为单态位点;赵村种群的杂合性最低（H=0.112）,伍姓湖种群最高（H=0.229）;赵村种群与伍姓湖种群间的Nei‘s遗传距离为0.068,可视为1个大的种群,而黄陵种群与赵村种群和伍姓湖种群的Nei‘s遗传距离分别为0.247和0.218。考虑到赵村和伍姓湖之间的地理距离（41km）比太原黄陵（357km）要近得多,结果提示3个种群地理距离与遗传结构差异之间存在相关关系。     

Variations de la malate déshydrogénase dans quatre espèces de Jaera albifrons: Etude génétique et variation géographique

Malate dehydrogenase has been detected in four species of the super-species Jaera albifrons. Two polymorphic enzymatic systems occur showing a one banded pattern for homozygotes and a three banded pattern for heterozygotes. Two independant autosomal loci control the variation as is shown by intra- and interspecific crosses. In European populations of the three species studied, MDH-1 is polymorphic and MDH-2 is monomorphic. In the American species, J. posthirsuta, the locus MDH-2 is polymorphic and MDH-1 is monomorphic.     

Population structure and gene flow of the Atlantic walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation

The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus , was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow ( Nm ) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land–Svalbard population, which were connected by moderate gene flow.     

Development of 10 microsatellite loci in the ling (Molva molva)

We developed primers for two dinucleotide and eight tetranucleotide microsatellite loci in a marine fish, the ling (Molva molva). All markers were obtained from partial genomic DNA libraries and characterized in 55 unrelated individuals from one putative population. The number of alleles ranged from five to 24 (average 10.5) per locus, and the observed heterozygosity ranged from 0.218 to 0.981 (average 0.643). No loci amplified in two other gadoid species tested, the Atlantic cod (Gadus morhua) and the tusk (Brosme brosme).     

马尾松GOT、LDH和MDH同工酶的遗传方式和连锁关系

本文采用聚丙烯酰胺凝胶电泳研究了马尾松三种同工酶的遗传方式和连锁关系。结果表明,GOT、LDH和MDH三种同工酶的遗传表达稳定,分别受4个、2个和4个位点控制。只有一对位点(MDH-3和MDH-4)间存在着紧密的连锁关系。     

Genetic characterization in four sciaenid species from the Arabian Sea

Four sciaenid species Johnieops dussumieri, Kathala axillaris, Pennahia macropthalmus and Otolithes ruber were analysed electrophoretically for genetic variation at 18 loci (16 in P. macropthalmus and O. ruber ). Twelve loci were polymorphic in J. dussumieri , 10 in K. axillaris , three in P. macropthalmus and 12 in O. ruber ( P <0·99). Average heterozygosity ranged from 0·033 ± 0·100 to 0·070 ± 0·122. The allele frequencies of 14 loci were used to estimate Nei's genetic distance (). The values ranged from 0·334 to 0·612. Three isozyme loci ( LDH-B*, MDH-2* and G3PDH-1* ) were found to be the most reliable species-specific markers.     

Congruence in genetic markers used to describe Mediterranean and Atlantic populations of European hake (Merluccius merluccius L. 1758)

Eight samples of the hake, Merluccius merluccius L., from the Mediterranean basin (370 fishes total) and one from the Atlantic ocean (50 fishes) were analysed in order to assess genetic variability and describe genetic population structure. Five polymorphic protein coding loci were scored (ADH*, PGI‐1*, PGI‐2*, PGM* and SOD‐1*) in eight samples, together with a haplotype variation of four samples, obtained from polymerase chain reaction/restriction fragment length polymorphism (PCR–RFLP) analysis on the mitochondrial DNA control region. The average value for observed heterozygosity was typically higher than expected (showing an excess of heterozygotes among the samples) whereas the haplotype diversity at mtDNA was very low. Samples originating from inside the Mediterranean basin appeared genetically homogeneous but the sample originating from the Atlantic was heterogeneous compared with the Mediterranean populations. Nuclear and mitochondrial gene analysis showed similar results supporting that the Strait of Gibraltar may be considered as a breakpoint area to gene flow.     

Developmental genetics in larvae,pupae and adults ofSepedon fuscipennis fuscipennis [Dipt.: Sciomyzidae]

An analysis of 28 enzyme loci throughout developmental stages ofSepedon fuscipennis fuscipennis Loew indicated that 16 were polymorphic and 4 were monomorphic in all stages. Nine loci were differentially expressed among the stages: EST-1, EST-2, MDH-2, MDH-3 and PGI-1 occurred only in larvae, AK-3 mainly in pupae, and AK-1, AO and HK-1 only in adults. The average heterozygosity ofS. f. fuscipennis was 0.146 (±0.028) across all stages.      

Population status of Greenland halibut <Emphasis Type="Italic">Reinhardtius hippoglossoides</Emphasis> (Walbaum, 1793) of the Laptev Sea

This is the first study to perform a comparative genetic analysis of Greenland halibut in the samples from the Atlantic (waters of west and east of Greenland), Arctic (Laptev Sea), and Pacific (the western part of the Bering Sea) ocean basins using seven microsatellite loci. The obtained data clearly demonstrate that the Greenland halibut population in the Laptev Sea belongs to the groups of the Atlantic Ocean basin. Apparently, the Greenland halibut of the Laptev Sea is represented by a dependent population, which is replenished due to the drift of immatures from the spawning grounds in the Barents Sea with the transformed Atlantic water flow along the continental slope. In addition, the Arctic population can be partially replenished due to the breeding of the halibut in local spawning grounds.     

Allozyme diversity in the tetraploid endemic Thymus loscosii (Lamiaceae)

BACKGROUND AND AIMS: Thymus loscosii (Lamiaceae) is a tetraploid perennial species endemic to the Ebro river basin (north-eastern Spain), which is included in the National Catalogue of Endangered Species. It is a tetraploid species (2n = 54), presumably an autotetraploid originated by the duplication of a 2n = 28 genome and the subsequent loss of two chromosomes. Allozyme electrophoresis was conducted to survey the levels and distribution of genetic diversity and to test the previous autopolyploid hypothesis for its origin. In addition, both in situ and ex situ conservation measures are proposed. METHODS: Eight populations were sampled for analysis by standard methods of starch gel electrophoresis, and six putative enzymatic loci were resolved (five consistently and one only partially). KEY RESULTS: Banding patterns exhibited no evidence of fixed heterozygosity and showed both balanced and unbalanced heterozygotes. In addition, most individuals showed a pattern consistent with the presence of three or four alleles at a single locus. High levels of genetic variability were found at population level (P = 85 %, A = 3.0, He = 0.422), in addition to a trend of an excess of heterozygotes. CONCLUSIONS: Allozyme data support the hypothesis that T. loscosii is an autotetraploid, and the high number of alleles at some loci may be due to repeated polyploidization events. The high values of genetic variation found in this species agree with those expected for tetraploids. The excess of heterozygotes may be due to some barriers to inbreeding (e.g. occurrence of gynodioecy) and/or selection for heterozygosity.     

Enzyme polymorphism in feral, outbred and inbred rats (Rattus norvegicus).

Polymorphism at 25 loci coding for liver enzymes was studied in two feral, three outbred and three inbred rat strains by starch gel electrophoresis. No variation was found at 14 loci, and a low degree of polymorphism was detected at three. Eight loci were polymorphic in more than one population. The average degree of heterozygosity per locus per individual feral rat was 0-07. The degrees of heterozygosity observed in the outbred and inbred strains were lower, from 0-006 to 0-012. Contrary to expectation, the inbred strains were neither monomorphic nor appreciably less heterozygous than the outbred ones. The heterozygosity of the inbred strains was primarily due to two polymorphic loci, G-3-pdh and alpha-Gpdh. The reason for this polymorphism is probably the superior homeostasis of the heterozygotes.     

Microsatellite DNA variability in the populations of muskoxen <Emphasis Type="Italic">Ovibos moschatus</Emphasis> transplanted into the Russian North

The muskoxen populations introduced to the Taimyr Peninsula and Wrangel Island in 1974 to 1975 were examined for sequence variation at seven microsatellite loci. Donor material originated from the populations of Banks Island (Canada) and Eastern Greenland. Relative to the allele frequencies, both introduced populations demonstrated rather strong deviation from the populations of the native range. At the same time, population allelic structures evidenced that they were closer to the Greenland populations. Estimates of genetic diversity at microsatellite loci (expected heterozygosity and the allele number) in the introduced muskoxen were found to be high for populations originating from a small number of founder individuals. In the immigrants, linkage disequilibrium and deviation of the genotype frequencies from the Hardy-Weinberg proportions were observed, which was mainly caused by the deficit of heterozygotes. The same pattern was also typical of native populations and was explained in terms of specific population structure and demographic processes. The latter were manifested as a periodic decline of the effective population size, resulting in the prevailing influence of genetic drift and inbreeding. The consequences of genetic drift were not as dramatic, as could be expected, which may be explained by a high mutation rate of neutral microsatellite loci and fast growth of the new populations.     

Homozygosity at a class II MHC locus depresses female reproductive ability in European brown hares

The link between adaptive genetic variation, individual fitness and wildlife population dynamics is fundamental to the study of ecology and evolutionary biology. In this study, a Bayesian modelling approach was employed to examine whether individual variability at two major histocompatibility complex (MHC) class II loci (DQA and DRB) and eight neutral microsatellite loci explained variation in female reproductive success for wild populations of European brown hare (Lepus europaeus). We examined two aspects of reproduction: the ability to reproduce (sterility) and the number of offspring produced (fecundity). Samples were collected from eastern Austria, experiencing a sub‐continental climatic regime, and from Belgium with a more Atlantic‐influenced climate. As expected, reproductive success (both sterility and fecundity) was significantly influenced by age regardless of sampling locality. For Belgium, there was also a significant effect of DQA heterozygosity in determining whether females were able to reproduce (95% highest posterior density interval of the regression parameter [−3.64, −0.52]), but no corresponding effect was found for Austria. In neither region was reproduction significantly associated with heterozygosity at the DRB locus. DQA heterozygotes from both regions also showed a clear tendency, but not significantly so, to produce a larger number of offspring. Predictive simulations showed that, in Belgium, sub‐populations of homozygotes will have higher rates of sterile individuals and lower average offspring numbers than heterozygotes. No similar effect is predicted for Austria. The mechanism for the spatial MHC effect is likely to be connected to mate choice for increased heterozygosity or to the linkage of certain MHC alleles with lethal recessives at other loci.     

Malate dehydrogenase isozymes in five species of sarcophagid flies (Sarcophagidae: Diptera)

Malate dehydrogenase banding patterns were analyzed by polyacrylamide gel electrophoresis in Sarcophaga ruficornis, S. argyrostoma, S. dux, S. invaria and S. peregrina. Two distinct zones of MDH activity, attributed to be the product of two gene loci, namely, MDH-1 and MDH-2 were observed. The MDH-1 locus revealed polymorphism for three electrophoretic phenotypes which are governed by two electromorphs MDH-1^a and MDH-1^b. The MDH banding pattern does not reveal any notable interspecific difference.     

Genetic characterisation of a domestic dog<Emphasis Type="Italic">Canis familiaris</Emphasis> breed endemic to South African rural areas

Allozyme electrophoresis (horizontal starch gel and PAGE) and histochemical staining techniques were used to study the genetic composition of an endemic southern African domestic dogCanis familiaris Linnaeus, 1758, the Africanis breed. Genetic differentiation was analysed at 21 protein-coding loci. The results were compared to those for three other populations/breeds: representatives of established Western breeds, crossbred dogs of Western descent from rural areas in South Africa, and indigenous Saluki dogs from the Middle East. Nine polymorphic loci were found (Ak-1,-2, Ck, Per, Hb, Po-A-1 to-3 andPo-Tf). Two unique alleles at theCk andPo-A-2 loci separated the Africanis breed from the other groups. There were also significant differences between Africanis and the other breeds in pair-wise comparisons of allelic frequencies at polymorphic loci. An assignment test, fixation index values, gene flow and genetic distance values indicated a closer genetic association between the Africanis and Saluki breeds than with dogs of Western origin. This finding supports archaeological evidence that the endemic Africanis breed was introduced from the Middle East into Africa thousands of years ago, and not through later western influences. The average heterozygosity ranged from 0.106–0.15, with least heterozygosity in the Africanis and most in the rural crossbred group. The percentage of polymorphic loci, the mean number of alleles per locus (biologically more significant than heterozygosity), and conformation of genotypes to Hardy-Weinberg proportions showed no evidence of recent loss of genetic diversity in Africanis. Genetic differentiation and support of archaeological evidence by genetics indicate that the endemic southern African domestic dog breed is unique.     

Protein variation in wild Atlantic salmon, with particular reference to southern Ireland

The extent of genetic variation in wild Atlantic salmon parr, Sulmo salur L., from river systems in Ireland, Iceland and eastern Canada, was investigated using starch gel electrophoresis. Within Ireland, seven polymorphic enzyme loci ( sAAT-4 *, GPI-1 *, IDDH-1 *, IDDH-2 *, IDHP-3 *, MDH-3 * and mMEP-2 *) were screened in nine different rivers and nine tributaries from the River Blackwater. Significant heterogeneity in gene frequencies occurred between riverine samples and between samples from tributaries of the River Blackwater. Variation between tributaries was as great as between rivers elsewhere in the country. Levels of population differentiation were comparable to those found in other regions throughout the range of the species, and temporal stability in gene frequencies was apparent when the results were compared with previously published data. Screening of riverine samples from Iceland and eastern Canada (Newfoundland and New Brunswick) allowed the Irish results to be considered in a broader context. Irish salmon cluster in the western European group, to which may be added Icelandic populations. Salmon from eastern Canada show a high level of genetic distinctiveness from the European group.     

Morphology and biochemical genetics of Atlantic halibut, Hippoglossus hippoglossus (L.), from various spawning grounds

Potential phenotypic/genotypic differentiation of Atlantic halibut, Hippoglossus hippoglossus (L.), samples from two spawning grounds in north Norway (Malangen and Sørøysund) were studied. In addition, the genetic relationship between fish from north Norway, mid–Norway (Folia) and western Greenland (off Fredrikshåb) was investigated. Uni– and multivariate analyses of 15 morphometric measurements and six meristic counts revealed a considerable degree of homogeneity between Malangen and Sørøysund. No morphological characters were thus found suitable as diagnostic tools in the classification of potential halibut stocks. As determined from electrophoretic studies, the allelic distribution at the four polymorphic loci ADA, PGI–2, PGM–2 , and UTP (unidentified tissue protein) did not vary significantly when all four samples (Folia, Malangen, Sørøysund and Greenland) were considered together. However, when the Norwegian coast samples were split into a northern (Sørøysund and Malangen) and a middle (Folla) area, and each locus was regarded isolated, significant heterogeneity was detected at the PGM–2 locus, thus giving evidence for a potential heterogeneity along a north–south axis.