Loci Gpi Research Articles

Genetic structure of the western rock lobster, Panulirus cygnus, with the benefit of hindsight

Allozyme variation was used to investigate the genetic structure of the western rock lobster, Panulirus cygnus, along the coast of Western Australia. The study involved genetic surveys in 1980 and 1994. The first survey showed strong suggestions of latitudinal variation at two polymorphic loci, EST and GPI, but these suggestions were statistically suspect. With the benefit of hindsight gained from 1980, the 1994 survey was designed to examine more directly the suggestion of latitudinal genetic subdivision in this species. No evidence of genetic subdivision was found at either the EST or the GPI locus. In addition, the average FST value over nine polymorphic loci was a very low 0.0002. The evidence is consistent with current interpretations that P. cygnus is a single, panmictic population. In contrast with this spatial genetic homogeneity, however, there were significant changes in allelic frequencies at the GPI locus between 1980 and 1994, indicating genetic differences among cohorts.

Effects of an Odh null allele and a GPI low-activity allozyme on shell length in laboratory-reared Mytilus edulis

Mytilus edulis L. heterozygotes with a null allele at the octopine dehydrogenase (Odh) locus or an allele coding for low activity at the glucose phosphate isomerase (Gpi) locus were found to grow significantly faster (p(0.05) than other juvenile mussels in the same laboratory cultures. Odh null homozygotes were not significantly different in growth from mussels with active Odh alleles. No additive effects were seen in individuals which had both the Odh null allele and the allele coding for low GPI activity. These results do not support the contention that null alleles are a significant cause of the observed correlation between multiple-locus heterozygosity and fitness in mussels. The apparent deficiencies of heterozygotes against Hardy-Weinberg expectations observed at the Odh locus in two Netherlands M. edulis populations can be more than accounted for by the null-allele frequency calculated, assuming Hardy-Weinberg equilibrium, from the observed frequency of null homozygotes in these populations.

BglII and HincII detect polymorphisms at porcine GPI locus.

Animal GeneticsVolume 26, Issue 3 p. 207-208 BglII and HincII detect polymorphisms at porcine GPI locus V Russo, Corresponding Author Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, Italy2Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorR Davoli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorD Nicoli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorP Zambonelli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this author V Russo, Corresponding Author Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, Italy2Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorR Davoli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorD Nicoli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this authorP Zambonelli, Institute of Allevamenti Zootecnici, Faculty of Agriculture, Bologna University, Via F.lli Rosselli 107, 42100 Reggio Emilia, ItalySearch for more papers by this author First published: June 1995 https://doi.org/10.1111/j.1365-2052.1995.tb03173.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume26, Issue3June 1995Pages 207-208 RelatedInformation

Allozyme variation within and between three populations of browntop(Agrostis capillaris)

Abstract Allozyme variation in the tetraploid browntop (Agrostis capillaris) cultivar ‘Grasslands Muster’, and two resident hill country browntop populations was investigated. The aim was to develop a set of genetic markers that would allow this cultivar to be reliably distinguished from the resident populations, enabling persistence of this cultivar in hill country pastures to be monitored following oversowing. Screening of 17 enzyme systems yielded three polymorphic loci: Gpi; Pgm; and Mdh. For Gpi, 12 alleles were found among the three populations sampled, allele frequencies ranging from 0 to 0.245. Pgm showed six alleles, and frequencies ranged from 0 to 0.792. Mdh could only be analysed in terms of phenotype frequencies, and four phenotypes were recognised, with frequencies ranging from 0 to 0.6. Pairwise G‐tests and the calculation of geometric distances between the populations on the basis of this data suggested that allele frequencies at the loci Gpi and Pgm differ sufficiently between ‘Grasslands...

Genetic differentiation across the Western Pacific populations of the hydrothermal vent bivalve Bathymodiolus spp. and the Eastern Pacific (13°N) population of Bathymodiolus thermophilus

Deep-sea mussels, closely related to the Bathymodiolus genus and individuals of Bathymodiolus thermophilus, were collected on hydrothermal vents of the Lau and North-Fiji back-arc basins (Western Pacific) and at 13°N on the East Pacific Rise, respectively. Separate tissue homogenates were submitted to starch gel electrophoresis in order to study the genetic structure of the populations at 11 enzyme loci. Significant departures from the Hardy-Weinberg equilibrium were found at Aat-1, Gpi and Pgm loci without any location specificity. All the observed departures corresponded to heterozygote deficiencies that are common in mollusc bivalves. The genetic variability of these mussels was low in all samples, especially for the North-Fiji population. The genetic distances measured between populations demonstrated that significant genetic differentiation occurs between the Western Pacific mussel populations and the Eastern Pacific B. thermophilus, whereas gene flow appeared to be maintained between the two back-arc basins. The presence of both shared heterozygotes and genetic distances found between the western and the eastern populations do not allow us to separate these allopatric forms as distinct sibling species.

Multilocus enzyme electrophoresis on agarose gel as an aid to the identification of entomopathogenic Bacillus sphaericus strains.

Sixty strains of Bacillus sphaericus, including 31 insect pathogens were studied by multilocus enzyme electrophoresis and were classified into 44 zymovars (electrophoretic types). Among the entomopathogenic strains, 11 belong to the same zymovar (Z59) indicating a widespread frequent genotype. Bands of enzyme activity were not detected among the strains for the loci GPI (E.C.5.3.1.9), G6P (E.C.1.1.1.49), 6PG (E.C.1.1.1.44) and ME (E.C.1.1.1.40). The enzymatic loci NP (E.C.2.4.2.1) and ACON (E.C.4.2.1.3) were monomorphic while the other enzymes, MDH (E.C.1.1.1.37), LeDH (E.C.1.4.1.9), ADH (E.C.1.4.1.1), EST (E.C.3.1.1.1), PEP-2 (E.C.3.4.11.1), PEP-3 (E.C.3.4.11) and PEP-D (E.C. 3.4.13.9) were polymorphic. The genetic variation in the non-insect pathogenic group seemed to be greater than in the entomopathogenic group. This latter group appears to be distinct from other strains of these species. All insect pathogens were recovered in the same phenetic cluster and a diagnostic allele is reported for the identification of entomopathogenic strains.

Mating type, nuclear DNA content and isozyme genotypes of Irish isolates of Phytophthora infestans

P. infestans isolates collected in Ireland in 1988 and 1989 were analyzed for mating type, nuclear DNA content, and isozyme genotypes at the Gpi (glucosephosphate isomerase) and Pep (peptidase) loci. Of 35 isolates collected, 8 were found to be of A2 mating type, 25 were of A1 mating type, and 2 were self-fertile. Isozyme genotypes observed included Gpi 90/100 Pep 83/100, Gpi 90/100 Pep 100/100, Gpi 100/100 Pep 83/100 , and Gpi 100/100 Pep 100/100 . Nuclear DNA content measurements revealed the presence of putative diploid, triploid, and tetraploid individuals in the population. These data indicate that Irish isolates clearly represent the ‘new’ P. infestans population which has become prevalent in Europe and other countries since the early 1980s.

Nuclear DNA content, allozyme phenotypes and metalaxyl sensitivity of Phytophthora infestans from Japan

Thirty isolates of Phytophthora infestans from all districts of Japan (15 of Al mating type and 15 of A2 mating type) were analyzed for nuclear DNA content (ploidy), allozymes and response to metalaxyl. Twenty-one isolates produced sufficient zoospores for analysis of nuclear DNA content; all Al mating type isolates were putative tetraploids, while A2 isolates were all putative triploids. Each mating type was strongly associated with specific phenotypes at the polymorphic allozyme loci Gpi (glucosephosphate isomerase) and Pep (peptidase). All A2 isolates had the phenotype Gpi 100/100 Pep 100/100, whereas the Al isolates were either Gpi 86/100 Pep 92/100 or Gpi 86/100 Pep 100/100. Metalaxyl resistance was only noted among isolates of A2 mating type. Our data suggest that the 1988 Japanese P. infestans population was likely comprised of two separate non-interbreeding subpopulations of opposite mating type.

The CCAAT/enhancer binding protein (C/EBP α) gene ( CEBPA) maps to human chromosome 19q13.1 and the related nuclear factor NF-IL6 (C/EBP β) gene ( CEBPB) maps to human chromosome 20q13.1

The CEBPA gene encoding CCAAT/enhancer binding protein (C/EBP alpha) has been mapped to human chromosome 19 and the CEBPB (formerly TCF5) gene encoding NF-IL6 (C/EBP beta) to human chromosome 20 by Southern blot analysis of Chinese hamster x human and mouse x human somatic cell hybrids. CEBPA has been further mapped to 19q13.1 between the loci GPI and TGFB using human x hamster somatic cell hybrids containing restricted fragments of human chromosome 19. This position was confirmed by fluorescence in situ hybridization. Furthermore, CEBPB has been mapped to 20q13.1 by fluorescence in situ hybridization.

Genetic divergence and a hybrid zone between Baltic and North Sea Mytilus populations (Mytilidae: Mollusca)

Populations of the common mussel (Mytilus edulis) from the North Sea area (Skakerrak-Kattegat) and those from the Baltic Sea are almost diagnostically differentiated at five out of 22 studied allozyme loci; at a further seven loci, alleles predominant or common in one area are nearly absent in the other. Genetic distance was estimated at 0.28; this is similar to the distances of these populations to the Mediterranean mussel M. galloprovincialis. The three mussel types obviously represent equal evolutionary divergence from one another, and should also be taxonomically equally separated; a semispecies rank within a more comprehensive M. edulis complex or superspecies is suggested. The age of the Baltic mussel type (‘M. trossulus’), as an independent evolutionary lineage, is probably far greater than that of the post-glacial Baltic Sea. Allele frequencies change gradually and in parallel when entering from the Kattegat through the Sound into the Baltic. Only a slight Wahlund effect at the strongly diverged Gpi and Pgm loci was found in intermediate populations, indicating that extensive hybridization of the two taxa takes place in the area. However, strong interlocus genotypic associations suggest that selection against hybrids is intense in later generations; the c. 100 km wide hybrid zone is narrow relative to the dispersal distance. The genotypic structure of the Lap locus does not conform with those of the other loci studied in the hybrid zone; it cannot be viewed merely as a neutral marker of the process of hybridization.

Patterns of gene expression during Prochilodus scrofa (Characiformes, Prochilodontidae) embryogenesis—III. Glucose-6-phosphate isomerase

1. 1. The patterns of expression of the glucose-6-phosphate isomerase loci in the differentiated adult tissues and in the early embryonic stages (1.30–180 hr post-fertilization) of curimbatá, Prochilodus scrofa, were investigated. 2. 2. As in other teleost species, two bidirectionally divergent GPI loci, GPI-A ∗ and GPI-B ∗ were differentially expressed among the tissues and sequentially during the embryogenesis of this species. The GPI-B ∗ locus was expressed predominantly in white skeletal muscle, and the A ∗ locus in all other tissues examined. 3. 3. GPI-A 2 was present throughout embryogenesis and it was the only GPI isozyme until 12 hr and 30 min after fertilization (pre-hatching). The GPI-B subunits were first detected only later in development, varying in the different mating types in their first appearance from stage 5 to 7 (12 hr 30 min–34 hr after fertilization), mainly as a very low activity heterotetramer form suggesting the concomitant synthesis of both subunits at this time. 4. 4. The timing of the appearance of the B subunits which predominate in adult skeletal muscle coincided with the first visible muscular contributions of the curimabatá larvae. 5. 5. One genetic variant at GPI-A ∗ locus, A ∗87 , and three at the B ∗ locus, B ∗500 , B ∗ - 200 and B ∗ - 400 were detected in adult curimbatá. In the A100 2 B100/-200 and A100/87 B100/-200 heterozygous embryos (offspring from mating type II and III, respectively) both paternal alleles were asynchronously expressed. 6. 6. Following stage 6 (hatching) there was a marked increase in total GPI activity and its maximal levels were obtained 60–105 hr post-fertilization, when the yolk sacs of the larvae were reduced (60 hr) or totally reabsorbed (105 hr), and the larvae were free swimming and feeding.

Genetic differentiation of the Iceland scallop Chlamys islandica (Pectinidae) in the northern Atlantic Ocean

Allozymic variation at gene loci encoding for glucosephosphate isomerase, phosphoglucomutase and superoxide dismutase was investigated In populations of Chlarnys islandica from waters around Jan Mayen, Spitsbergen, Bear Island and northern Norway. The Gpi locus was particularly polymorphic with at least 12 different alleles and a mean heterozygosity of 84 % Half the individuals were heterozygous at Pgm-2 and between 30 and 40 % at Sod. The high polymorphism at Gpi runs counter to an earlier hypothesis suggesting a positive correlation between environmental variability and Gpi polymorphism of pectinids. Pgm-2 and Sod revealed significant allele frequency heterogeneity among the different areas, Gpi only when the effective number of alleles was considered. The species has a large dispersal potential during a long planktonic larval stage, but information on the surface current system in the North Atlant~c suggests that restr~cted gene flow, with possible contributions from selective constraints, account for the observed pattern in gene variability. It is suggested that the conservative approach of managing each area as if it contained discrete genetic units of the species should be adopted.

Genetic studies of laboratory reared Mytilus edulis. I. Genotype specific selection in relation to salinity

Significant deviations from the Hardy-Weinberg equilibrium in natural populations of bivalves may be due to a number of factors such as the Wahlund effect, null alleles and selection, and it is often difficult to decide which of these factors is operating. The use of laboratory controlled single crosses and mass matings, where the genotypes of the parents are known, can provide strong evidence for selection when deviations from expected genotype frequencies are observed in the offspring. Several cultures of offspring from a single cross and from a mass mating of the mussel, Mytilus edulis, were reared through the larval stage at either 32 or 25 parts per thousand salinity. At the early post-larval stage salinities were altered for some cultures while others remained unchanged. Samples were taken for electrophoresis as post-larvae and again as juveniles and were scored at the Lap, Pgm, Odh, Hex, Pgk and Gpi loci. Significant deviations from expected frequencies were observed at many loci in the offspring but these deviations did not appear to be related to salinity except at the Lap locus. The allele Lap94 was selected against at low salinity during the post-larval to juvenile stage, but no such selection occurred at low salinity during the larval stage. The data fit Koehn's (1985) model of post-larval selection at the Lap locus in mussels in Long Island Sound, USA, but suggest that there may be ontogenetic variation in fitness at this locus. Results at the Pgm and Gpi loci indicate that these loci are probably acting as markers for other loci on the same chromosome which have a strong effect on fitness. Density dependent factors may have caused some of the non-random mortality amongst offspring which was apparently independent of salinity.

Isoenzyme Studies on two Field Populations of Glossina pallidipes Austen (Diptera, Glossinidae) in Kenya

Electrophoretic studies were carried out on isozymes of Glossina pallidipes to determine whether there are any genetic differences between natural populations from an area free of sleeping sickness (Nguruman) and an area where sleeping sickness is endemic (Lambwe Valley) in Kenya. Out of 12 enzymes examined, two enzymes, GPI and PGM, showed high polymorphism in the two populations, while the other 10 enzymes were all monomorphic. At the GPI locus, at least five alleles were detected, and two alleles were found at the PGM locus. There was a difference in the frequency of isozyme patterns between males and females, indicating that the PGM locus is on the sex-linked chromosome (X-chromosome). Nei’s genetic distance (D) was 0.00154 between the two populations, which is the value within the range for local populations in different organisms examined so far. Some difference between the two populations was found in the level of average heterozygosity (H) and in allelic composition of the GPI locus, that is, the Lambwe Valley population is more heterogeneous than the Nguruman population.

Lasaea rubra (Montagu) (Bivalvia : Erycinacea), an apomictic crevice-living bivalve with clones separated by tidal level preference

The populations of the crevice-living bivalve Lasaea rubra (Montagu) on Anglesey consist at least of three electromorphic clones. The allozymes at the Gpi and Pgm loci allow these clones to be distinguished. At both these loci and in all three clones, the enzymes appear to consist of fixed heterozygotes. Several other enzyme systems also exist apparently as fixed heterozygotes. It follows that parthenogenesis in L. rubra on Anglesey and probably elsewhere is effectively apomictic, the eggs developing without any overt meiotic process or segregation of alleles at any time in the life history or between numerous generations of clonal reproduction. The distribution of the three clones throughout Anglesey and along the south coast appears to be strongly correlated with tidal level. Each clone can occupy any type of crevice habitat, whether the crevices are formed by rock, barnacle shells, tangled byssus threads, or axils of branching algae. Clone 1 is concentrated at high water spring tide level. Clone 2 favours high water neap tide level to mean tide level, and Clone 3 dominates the lowest crevices on the shore or attached to algae submerged in tide pools. It follows that, although no morphological differences have yet been discerned, each clone deserves to be recognized as a separate species, genetically isolated and with its own habitat preferences for which it is presumably physiologically adapted.

Electrophoretic variants characteristic of heterozygotes in haploid laver Porphyra sp.

Starch gel electrophoresis was carried out to survey the genetic variation in the haploid lavers of the Porphyra sp. claimed to be Porphyra renera. Eleven enzyme loci were resolved and scored. Eight of the eleven loci were monomorphic, while the three loci, catalase (CAT), glucosephosphate isomerase (GPI) and mannosephosphate isomerase (MPI) showed polymorphism. At the Gpi and Mpi loci, a number of lavers had electrophoretic phenotypes characteristic of heterozygotes. In order to compare with Porphyra yezoensis, the allelic frequencies were calculated on the assumption that the heterozygous phenotypes possessed two alleles. The genetic distance between Porphyra sp. and Porphyra yezoensis was 0.1511, indicating the differentiation of the subspecies level. Electrophoretic phenotypes characteristic of heterozygotes is unexpected, since Porphyra lavers are in a haploid phase. Our findings suggest that the plant is either in the diploid phase or that duplication occurs in one of the chromosome sets.

The isozymes of glucose-phosphate isomerase (GPI-A2 and GPI-B2) from the teleost fish Fundulus heteroclitus (L.).

The fish, Fundulus heteroclitus (L.), like most advanced teleosts, possesses duplicate loci for the glycolytic enzyme, glucose-phosphate isomerase (D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9). The locus for the GPI-A2 (where GPI represents glucose-phosphate isomerase) isozyme is preferentially expressed in anaerobic tissues such as white skeletal muscle, while GPI-B2 predominates in aerobic tissues like liver and red muscle. We questioned whether this tissue specificity would be reflected in unique structural and functional characteristics of the respective isozymes. Consequently, an analysis of the two isozymes was undertaken. The enzymes were purified by a combination of ion-exchange chromatography and isoelectric focusing. Each isozyme was characterized as to native and subunit molecular weight, isoelectric pH, and susceptibility to thermal denaturation. Both were dimeric enzymes, with native molecular masses of 110 kDa. The isoelectric pH values for GPI-A2 and GPI-B2 were 7.9 and 6.4, respectively. Differences were apparent in thermal stability, i.e. GPI-A2 was more stable than GPI-B2. Kinetic properties were investigated as a function of both pH and temperature. The Km values for fructose 6-phosphate (Fru-6-P) differed between the isozymes at low pH, but no significant differences were observed at higher pH. The inhibition constant (Ki) for 6-phosphogluconate (6-P-gluconate) was pH dependent. GPI-A2 was slightly more sensitive to 6-P-gluconate inhibition than GPI-B2 between pH 7.0 and 8.5. The Km for Fru-6-P was temperature dependent for the GPI-B2 isozyme, but relatively temperature independent for GPI-A2 between 10 and 35 degrees C. The Ki for 6-P-gluconate was temperature dependent for both isozymes. The Ki values for GPI-A2 were consistently lower than those for GPI-B2. Energies of activation differed between the two isozymes by 4.4 kcal with GPI-A2 having the lower value. While delta G values were identical for the isozymes, their delta H and delta S values differed significantly. The structural and kinetic differences that exist between the glucose-phosphate isomerase isozymes appear to be tailored to the unique metabolic demands of the tissues in which these Gpi loci are expressed.

An immunochemical method for the detection of the expression of human gene loci in human-rodent somatic cell hybrids with special reference to the GPI locus.

Species-specific antibodies, prepared against unpurified human enzymes in human-hamster somatic cell hybrids. Results of the detection of the expression of the human glucosephosphate isomerase gene locus (GPI) by electrophoretic and immunochemical techniques were concordant in 17 instances. The human GPI synthesized by fibroblasts derived from skin explants and by somatic cell hybrids retaining the human GPI locus, regardless of whether the human parental cells were lymphocytes or fibroblasts, appeared to be antigenically identical.

Differential gene expression in multilocus isozyme systems of the developing green sunfish

The patterns of expression of eight multilocous isozyme systems were investigated in the differentiated adult tissues and the early embryonic stages (0-210 hours after fertilization) of the green sunfish, Lepomis cyanellus. Enzymes encoded by approximately 23 gene loci were resolved by starch-gel electrophoresis and detected by specific histochemical staining. The developmental patterns of these isozyme systems appear to be the result of the diffential expression of the multiple gene loci. Isozymic forms of glucoseophosphate isomerase (GPI-A2), malate dehydrogenase (MDH-A2), and creatine kinase (CK-C2) were present in most differentiated tissues, in the unfertilized eggs, and in all stages of embryonic development. Closely homologous forms of these isozymes (GPI-B2, MDH-B2, and CK-A2) were expressed predominantly in skeletal muscle and were first detected at around the time of hatching (38-42 hours). The similar temporal and spatial patterns of gene expressions for the GPI, LDH, MDH, and CK loci suggest that the duplicates loci encoding enzymes, diverged in their regulation to patterns of differential gene expression which are similar for each enzyme system.

Linkage analysis of the multilocus glucosephosphate isomerase isozyme system in sunfish (Centrarchidae, Teleostii).

The purpose of the present investigation is to determine whether the two duplicated glucosephosphate isomerase (EC 5.3.1.9) loci Gpi-A and Gpi-B reside on the same chromosome in teleostean fishes. Interspecific sunfish hybrids were employed for the cross because of the different species-specific electrophoretic mobilities of the allelic isozymes at each GPI locus and because of their genomic compatibility. F1 sunfish hybrids, formed from a male warmouth (Lepomis gulosus) X female green sunfish (L. cyanellus) cross, were mated to form the F2 generation. The number of each of the nine different isozyme phenotypes, revealed by starch gel electrophoresis, was determined using 256 F2 individuals. The high frequency of recombinant phenotypes in the F2 generation indicated that the two GPI loci are not linked. An excess of F2 individuals heterozygous at both loci was observed and is interpreted as being caused by heterosis. The absence of linkage for the homologous loci encoding GPI subunits and for other multilocus isozyme systems is consistent with the postulate that the genomes of present-day vertebrates arose through one or more polyploidization events early in vertebrate evolution.