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PubMed1999

The molecular genetics of European ancestry.

In an earlier paper we proposed, on the basis of mitochondrial control region variation, that the bulk of modern European mitochondrial DNA(mtDNA) diversity had its roots in the European Upper Palaeolithic. Refining the mtDNA phylogeny and enlarging the sample size both within Europe and the Middle East still support this interpretation and indicate three separate phases of colonization: (i) the Early Upper Palaeolithic about 50,000 BP; (ii) the Late Upper Palaeolithic 11,000-14,000 BP; and (iii) the Neolithic from 8500 BP.

DNA, Mitochondrial↗
PubMed2006

Hemoglobin Loves Park [beta68 (E12) Leu-->Phe]: report of five cases including one originating from a de novo mutation.

Hemoglobin (Hb) Loves Park [beta68 (E12) Leu-->Phe] was identified in a 2-year-old Portuguese boy with anemia, microcytosis, and hypochromia. This Hb variant was detected by isoelectric focusing and quantified by reverse-phase high-performance liquid chromatography (HPLC) (48.4%), and the DNA mutation was identified by HBB (beta-globin gene) sequencing. Hematological and biochemical analyses performed on his parents revealed normal hematological parameters and normal hemoglobin and globin chain profiles. DNA sequence analysis of the HBB gene of both parents showed the absence of the Hb Loves Park mutation. Study of the haplotypes in the beta-globin gene cluster confirmed parenthood. Moreover, paternity was confirmed by the study of nine short tandem repeats (STRs) and four variable-number tandem repeat (VNTRs) loci. The most likely explanation for these results is that the Hb Loves Park mutation has occurred de novo in this family. The original American cases of Hb Loves Park, from a family of Italian origin, which were never published, as well as two additional cases, are also included in this report. Functional studies revealed that Hb Loves Park is stable and has a decreased oxygen affinity.

Amino Acid Substitution↗
PubMed1995

A boy with atrophic thyroiditis of prepubertal onset, who was positive for TSH-binding inhibitor immunoglobulins.

A 12 year old boy was admitted to our hospital because of short stature. From the age of 7, his growth velocity decreased and he manifested intolerance to low temperatures, hoarseness, dry skin, and slowness of thought and physical movement. On admission, his height was 129.8 cm (-3 s.d.) and his body weight was 43.2 kg (-0.5 s.d.). His clinical features also included relaxation phase of tendon reflexes, periorbital puffiness and cold skin but no struma. His bone age was 9 years. His serum thyroxine (T4), triiodothyronine (T3), free T4 and free T3 were low, while his thyrotropin was high. He was positive for antithyroglobulin antibodies, antimicrosomal antibodies, and TSH-binding inhibitor immunoglobulins. He was diagnosed as having atrophic thyroiditis. We also determined the HLA haplotypes of his family members. His father's HLA haplotypes were A2, BW61(a) and A24, BW52(b), while his mother's haplotypes were A24, BW52(c) and A30, BW60(d). The HLA haplotypes of both the patient and his younger brother showed a and d, while the patient's elder brother's HLA haplotypes showed b and c. His family members all had normal thyroid function, but his father was positive for antimicrosomal antibodies. In summary, we describe a rare case where the onset of hypothyroidism was prepubertal, where the pathogenesis may have involved TSH-receptor blocking antibodies, and where the inheritance of the disease may have been from the paternal side of the family.

Age of Onset↗
PubMed1992

Prognostically significant heterogeneity of cytoplasmic islet cell antibodies in relatives of patients with type I diabetes.

A significant proportion of relatives of patients with insulin-dependent (type I) diabetes with high titers of cytoplasmic islet cell autoantibodies (ICAs) do not progress to overt diabetes with up to 8 yr of follow-up. This may reflect that follow-up of such relatives has not been long enough to observe diabetes, that despite expression of identical ICAs, some relatives will not progress to diabetes; or that there is heterogeneity in what is identified as ICA. We identified a subset of ICA that was restricted in its species (not reacting with mouse islets) and cell-type reactivity within islets (beta-cell specific). Only one of eight relatives whose sera had the restricted pattern of reactivity progressed to overt diabetes, and on sequential evaluation, all but the one relative who progressed to diabetes have maintained normal first-phase insulin secretion to intravenous glucose. In contrast, by life-table analysis, 70% of relatives expressing nonrestricted ICA became diabetic within 5 yr of follow-up (1 of 8 vs. 16 of 25 diabetic at last follow-up, P less than 0.02). Moreover, preliminary data suggest a significant association of the human leukocyte antigen DQB1*0602 allele of DR2 haplotypes with the restricted ICA pattern (4 of 5 DQB1*0602 restricted vs. 0 nonrestricted ICA, P = 0.006). We propose that expression of a genetically determined restricted ICA pattern confers a markedly lower risk for progression to diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Genetic control of contact photosensitivity to tetrachlorosalicylanilide. I. Preferential activation of suppressor T cells in low responder H-2k mice.

The genetic control of contact photosensitivity (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA) was studied in H-2- and IgH-congenic mice. The H-2 complex was found to play a major role in determining the pattern of responsiveness, whereas the effect of the Igh locus on the response was not apparent. The H-2k haplotype was closely associated with low responders, whereas mice with the H-2b,d alleles were high responders. The responsiveness of the H-2k strains was converted from low to high levels by treatment with cyclophosphamide (CY) before photosensitization. Transfer of spleen cells from photosensitized H-2k mice showed a suppressive effect on the development of the CPS reaction of syngeneic recipients pretreated with CY. These spleen cells contained antigen-specific CD4+, CD8- suppressor T cells (Ts) that functioned in the induction phase of CPS. The in vitro proliferation of immune lymph node T cells pulsed with photohapten-coupled cells plus peritoneal adherent cells was suppressed by the addition of anti-I-A monoclonal antibody in both H-2d and H-2k strains, suggesting that the I-A molecule are responsible for inducing the positive immune response. On the other hand, such proliferation was significantly enhanced by the addition of anti-I-E alpha antibody in H-2k, but not H-2d, mice. This implies that the low responsiveness of CPS in the H-2k strain is due to the preferential activation of Ts via I-Ek molecules. The present observation further supports the important role of the I-E molecule in the suppressor circuit of CPS to TCSA.

Animals↗
PubMed1995

Recurrent episodes of acute hepatitis associated with LKM-1 (cytochrome P450 2D6) antibodies in identical twin brothers.

BACKGROUND/AIMS: Liver/kidney microsomal antibodies have been noted in liver disease of different etiology, e.g. in autoimmune hepatitis, chronic hepatitis C and D virus infection and in drug-induced liver disease. Unlike these, acute hepatitis of unknown etiology associated with high-titer liver/kidney microsomal-1 antibodies (cytochrome P450 2D6) is reported in identical twin brothers. METHODS: Patients were studied using clinical, biochemical, serological and immunological methods, as well as liver biopsy. RESULTS: The acute icteric episodes were followed by spontaneous remission with complete normalization of liver function tests and liver histology. During the acute phase, serum titer for liver/kidney microsomal-1 antibodies (detected by indirect immunofluorescence, ELISA and Western blot analysis) was exceedingly high and decreased gradually thereafter. Hepatitis C and D virus infection were excluded by repeated serological testing; exposure to drugs or chemicals was not evident. Concomitant autoimmune disease was not detectable. HLA typing for class 1 and 2 antigens was positive for the HLA haplotype DQ2, but negative for HLA B4, B8, DR3 and DR4. CONCLUSIONS: The present observations might suggest a hitherto unreported form of acute hepatitis of unknown etiology, distinct from other liver diseases in which liver/kidney microsomal antibodies have been described so far.

Acute Disease↗
PubMed2025

Severus detects somatic structural variation and complex rearrangements in cancer genomes using long-read sequencing.

For the detection of somatic structural variation (SV) in cancer genomes, long-read sequencing is advantageous over short-read sequencing with respect to mappability and variant phasing. However, most current long-read SV detection methods are not developed for the analysis of tumor genomes characterized by complex rearrangements and heterogeneity. Here, we present Severus, a breakpoint graph-based algorithm for somatic SV calling from long-read cancer sequencing. Severus works with matching normal samples, supports unbalanced cancer karyotypes, can characterize complex multibreak SV patterns and produces haplotype-specific calls. On a comprehensive multitechnology cell line panel, Severus consistently outperforms other long-read and short-read methods in terms of SV detection F1 score (harmonic mean of the precision and recall). We also illustrate that compared to long-read methods, short-read sequencing systematically misses certain classes of somatic SVs, such as insertions or clustered rearrangements. We apply Severus to several clinical cases of pediatric leukemia/lymphoma, revealing clinically relevant cryptic rearrangements missed by standard genomic panels.

Humans↗
PubMedDate not supplied

Germline mosaicism in Coffin-Lowry syndrome.

We have identified a Coffin-Lowry syndrome pedigree where the disorder is associated with a novel splice site mutation in the RSK2 gene, leading to in-phase skipping of exon 5. Western blot analysis, using an antibody directed against the C-terminus of RSK2, failed to reveal RSK2 in this patient, suggesting strongly that the resulting internally deleted protein is unstable. The mutation was present in the DNA of one affected son and one manifesting daughter but was absent in two asymptomatic daughters, who carry the at-risk haplotype, and in the mother's somatic cell (lymphocyte) DNA. The results are consistent with the mutation arising as a postzygotic event in the mother, who therefore is a germinal mosaic. The application of linked markers to identify the disease allele for conventional genetic counselling would have been misleading in this family. This observation again highlights the importance of precise identification of the disease-causing mutation.

Abnormalities, Multiple↗
PubMed2006

Mannan binding lectin and viral hepatitis.

Mannan binding lectin (MBL) is a pattern recognition molecule of the innate immune system that binds to sugars on the surface of invading micro-organisms. Target binding, complement activation and other functions of MBL are dependent on the presence of multiple carbohydrate recognition domains. Several polymorphisms in the promoter and structural regions of MBL2 adversely affect the plasma concentration and oligomeric state of MBL. The possession of mutant alleles has been linked to disease outcome for a variety of bacterial and viral infections. Viral hepatitis is caused by unrelated viruses referred to as hepatitis virus A-E. The disease usually has both acute and chronic phases, the latter leading to cirrhosis and hepatocellular carcinoma. Hepatitis viruses B and C (HBV and HCV, respectively) are a significant cause of morbidity worldwide. HBV encodes envelope glycoproteins termed large, middle, and small that may exist in glycosylated or unglycosylated forms on the virion. An interaction between HBV glycoproteins and MBL has been demonstrated in vitro. Significant associations between MBL levels, determined by MBL2 haplotypes, and HBV persistence and disease progression have been described. HCV encodes two highly glycosylated envelope proteins, E1 and E2, which are potential targets for interaction with MBL. Mutant MBL2 haplotypes have been linked to disease progression and response to therapy in HCV infection. Here we summarise the effect of MBL2 polymorphisms on MBL function and how this may relate to disease outcome in HBV and HCV infection.

Hepacivirus↗
PubMed2000

A deterministic genetic model for sympatric speciation by sexual selection.

A deterministic haploid genetic model confirms and explores in more detail the results of our previous individual-based simulation model for sympatric speciation by sexual selection. With the deterministic model, we are able to elucidate parameter dependence by phase plane analysis. We clarify how and why sympatric speciation by sexual selection can happen in a number of ways: (1) Female preferences for or against particular types of males have different effects. Whereas the former affects how readily speciation is invoked, the latter changes the stability of speciation equilibrium. (2) When there is no cost on male ornamentations, speciation is triggered regardless of initial haplotype frequencies if sufficient female preference is provided. (3) There exists a threshold for female initial frequencies for speciation to be invoked, but male initial frequencies have little effect. (4) A small cost on female mate choice does not cancel speciation, but when large, it greatly reduces the possibility of speciation.

Animals↗
PubMed2003

Selective depletion of donor alloreactive T cells without loss of antiviral or antileukemic responses.

Poor immune reconstitution after haploidentical stem cell transplantation results in a high mortality from viral infections and relapse. One approach to overcome this problem is to selectively deplete the graft of alloreactive cells using an immunotoxin directed against the activation marker CD25. However, the degree of depletion of alloreactive cells is variable following stimulation with recipient peripheral blood mononuclear cells (PBMCs), and this can result in graft versus host disease (GVHD). We have refined this approach using recipient Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) as stimulators to activate donor alloreactive T cells. Our studies demonstrate that allodepletion with an anti-CD25 immunotoxin following stimulation with HLA-mismatched host LCLs more consistently depleted in vitro alloreactivity than stimulation with host PBMCs, as assessed in primary mixed lymphocyte reactions (MLRs). Allodepletion using this approach specifically abrogates cytotoxic T-cell responses against host LCLs. In interferon-gamma (IFN-gamma) enzyme-linked immunospot (ELISPOT) assays, antiviral responses to adenovirus and cytomegalovirus (CMV) were preserved following allodepletion. Likewise, using HLA-A2-pp65 tetramers, we have shown that the frequency of CMV-specific T cells is unaffected by allodepletion. Moreover, the donor anti-EBV response is partially retained by recognition of EBV antigens through the nonshared haplotype. Finally, we studied whether allodepletion affects the response to candidate tumor antigens in myeloid malignancies. Using HLA-A2-PR1 tetramer analysis, we found that the frequency of T cells recognizing the PR1 epitope of proteinase 3 was not significantly different in allodepleted and unmanipulated PBMCs from patients with chronic myeloid leukemia (CML) undergoing transplantation. Based on these data, we have embarked on a phase 1 clinical trial of addback of allo-LCL-depleted donor T cells in the haplo-identical setting.

Cell Line, Transformed↗
PubMed1998

Partially mismatched pediatric transplants with allogeneic CD34(+) blood cells from a related donor.

This was a phase I, multi-center study of 13 pediatric patients (median age, 11 years) to evaluate toxicity, hematopoietic recovery, and graft-versus-host disease (GVHD) after allogeneic transplantation of enriched blood CD34(+) cells obtained from genotypically haploidentical but partially HLA-mismatched related donors (8 parents and 5 siblings). With regard to rejection, donor HLA disparity was 1 (5), 2 (6), or 3 loci (2). With regard to GVHD, recipient HLA disparity was 0 (1), 1 (3), 2 (8), or 3 (1). The patients suffered from acute myelogenous leukemia (6), chronic myelogenous leukemia (4), acute lymphoblastic leukemia (2), or hemolytic anemia plus immunodeficiency disorder (1). To reduce the risk of graft failure through the infusion of a large amount of stem cells, peripheral blood cells (PBC) were mobilized by recombinant granulocyte colony-stimulating factor (G-CSF; lenograstim, 10 microgram/kg/d for 5 days) and collected by 2 to 5 aphereses. To both enhance engraftment and reduce GVHD, CD34(+) cells were enriched using immunomagnetic procedures with the Baxter ISOLEX 300 system (Baxter Healthcare Corp, Irvine, CA) and cryopreserved. After variable cytoreductive regimens, a median of 7.7 (range, 2.2 to 14) x 10(6)/kg of CD34(+) cells and 1.03 (0.05 to 2.09) x 10(5)/kg CD3(+) cells were infused. Using Center-specific posttransplant supportive care and immunosuppressive GVHD prophylaxis, two patients experienced early death; one from veno-occlusive disease at day 17 and one from sepsis at day 18. Nine of 11 patients showed signs of engraftment; however, subsequent rejection was seen in 4 patients, 2 of whom had autologous recovery. Eight patients were evaluated in the early phase of marrow recovery. The median number of days to achieve an absolute granulocyte count of 0.5 x 10(9)/L was 14 (range, 9 to 20) and that to achieve a platelet count of 20 x 10(9)/L was 17.5 (range, 12 to 23). Donor chimerism persisted in five patients until death or current survival. All of the surviving patients with functioning-donor-type hematopoiesis were given total body irradiation. De novo acute GVHD (grades II and IV) was observed in two of the eight evaluated patients. Scheduled donor lymphocyte infusion (DLI), using the CD34(-) fraction, was administered to four patients, free of de novo acute GVHD, beginning between 28 to 43 days after transplant. Three of these patients developed acute GVHD (grades I, II, and IV). Cytomegalovirus infection was a major infectious complication but was successfully managed with gamma-globulin and gancyclovir treatment with or without additional DLI. Five patients are currently surviving, free of disease, with a follow-up ranging from 476 to 937 days. Each survivor has functioning hematopoiesis, three of donor origin and two of autologous origin. In conclusion, our results show that enriched blood CD34(+) cells from a mismatched haploidentical donor are a feasible alternative source of stem cells, but do not appear to ensure engraftment. Because none of the patients who were administered DLI survived, the therapeutic efficacy and safety of periodic DLI, as an integrated part of such transplants, needs to be clarified in further studies.

Adolescent↗
PubMed1996

Novel germline p16 mutation in familial malignant melanoma in southern Sweden.

The p16 (CDKN2/MTS1/INK4a) malignant melanoma susceptibility gene was analyzed in 10 melanoma kindreds from southern Sweden using single-stranded conformation polymorphism analysis of all three exons and flanking intron regions followed by sequence analysis. A novel germline mutation, constituting an in-frame 3-bp duplication at nucleotide 332 in exon 2, was identified in two families (Lund M2 and M9). The mutation results in an insertion of Arg at codon 105, which interrupts the last of the four ankyrin repeats of the p16 protein, motifs which have been demonstrated as important in binding and inhibiting the activity of cyclin D-dependent kinases 4 and 6 in cell cycle G1 phase regulation. All five tested individuals of Lund M2 and M9 affected by melanoma were mutation carriers, as were five melanoma-free individuals. Other malignancies observed in gene carriers or obligate carriers included cervical, breast, and pancreatic carcinomas and a non-Hodgkin's lymphoma. Analysis of microsatellite markers adjacent to the p16 gene at chromosomal region 9p21 revealed that both families share a common haplotype, in keeping with a common ancestor.

Carrier Proteins↗
PubMed1992

Molecular genetic analysis of HLA-DR and HLA-DQ genes among anti-U1-70-kd autoantibody positive connective tissue disease patients.

OBJECTIVE: We have recently found that the presence of autoantibodies against the 70-kd polypeptide of U1 RNP (U1-70-kd) is associated with HLA-DR4 and DR2. To further characterize this association, we performed a molecular genetic analysis of HLA-DR and DQ genes among patients with autoantibodies against U1-70-kd. METHODS: The polymerase chain reaction (PCR), sequence-specific oligonucleotide hybridization, and solid-phase direct DNA sequencing of PCR-amplified DNA were utilized to analyze HLA-DRB1, DRB5, DQA1, and DQB1 genes. RESULTS: A comprehensive analysis of HLA-DRB1, DRB5, DQA1, and DQB1 from 27 patients and controls identified shared amino acids FDYFYQA (Phe, Asp, Tyr, Phe, Tyr, Gln, Ala) at positions 26, 28, 30-32, 70, and 73 of HLA-DRB1 on disease-associated haplotypes. CONCLUSION: A common cluster of shared amino acids, or a shared epitope, identified within HLA-DRB1 among anti-U1-70-kd autoantibody positive connective tissue disease patients may be important in regulating an autoimmune response to the U1-70-kd antigen.

Amino Acid Sequence↗
PubMed1999

Linkage of the Na,K-ATPase alpha 2 and beta 1 genes with resting and exercise heart rate and blood pressure: cross-sectional and longitudinal observations from the Quebec Family Study.

OBJECTIVE: To investigate whether genetic variations in the genes encoding the alpha and beta subunits of the Na,K-ATPase are linked with hemodynamic phenotypes. DESIGN AND PARTICIPANTS: Cross-sectional data based on 533 subjects (no antihypertensive medication) were obtained from 150 families of phase 2 of the Quebec Family Study, together with longitudinal data from 338 subjects (105 families) who had been measured 12 years earlier in phase 1 of the Quebec Family Study. MAIN OUTCOME MEASURES: Restriction fragment length polymorphisms were examined at the alpha 2 (exon 1 and exon 21-22 with BglII) and beta 1 (Msp I and Pvu II) loci of Na,K-ATPase. Hemodynamic phenotypes measured included systolic and diastolic blood pressure, heart rate and rate-pressure product at rest and during low-intensity exercise. RESULTS: Sib-pair analysis revealed relatively strong linkages (P = 0.0003-0.002) between the resting heart rate and rate-pressure product and the alpha 2 exon 21-22 marker and alpha 2 haplotype. Moreover, the alpha 2 exon 21-22 marker showed suggestive linkages (P = 0.01 to 0.043) with resting systolic blood pressure and exercise diastolic blood pressure, heart rate and rate-pressure product, and the alpha 2 haplotype with exercise diastolic blood pressure and rate-pressure product and the 12-year change in resting systolic blood pressure (P = 0.03 to 0.05). Both the beta 1 Msp I marker and the beta 1 haplotype were linked with the resting rate-pressure product (P = 0.007 and 0.003, respectively), and all beta 1 markers showed linkage with the change in resting systolic blood pressure (P = 0.00005 to 0.024). In men, there was a significant (P = 0.01) interaction between the alpha 2 exon 21-22 genotype and the postglucose plasma insulin level with regard to resting systolic blood pressure. CONCLUSIONS: These data suggest that the alpha 2 and beta 1 genes of Na,K-ATPase contribute to the regulation of hemodynamic phenotypes in healthy subjects.

Blood Pressure↗
PubMed1999

HLA-DR-DQ alleles and HLA-DP alleles are independently associated with susceptibility to different stages of post-schistosomal hepatic fibrosis in the Chinese population.

Abstract: Evaluation of human leukocyte antigen (HLA) class I and class II genes was performed on patients from China with Schistosomiasis japonica. Patients were categorized as grade 0 (n=44), grade I (n=81), grade II (n=99), or grade III (n=6) based on increasing severity of hepatic fibrosis due to repeated Schistosoma japonicum infections. These results show that the HLA-DRB1*1101-DQA1*0501-DQB1*0301 (Pc<0.02) and HLA-DRB1*1501-DRB5*0101 (Pc<0.02) haplotypes are associated with protection and susceptibility to grade I fibrosis, respectively, and that the HLA-DPA1*0103 -DPB1*0201 haplotype (Pc<0.02) is associated with protection from both grade II and III severe fibrosis. There was no association between HLA-B DNA haplotypes and the disease. These findings indicate that the HLA-class II molecules play a role in preventing or promoting fibrotic liver change after deposition with Schistosome eggs. Moreover, a tendency was observed within the HLA class II genes for the HLA-DR-DQ alleles to be associated with protection against early changes in liver fibrosis, whereas HLA-DP alleles were associated with protection from the late phase of fibrosis or severe hepatosplenic schistosomiasis.

Alleles↗
PubMed2006

Hb Marineo [beta70(E14)Ala-->Val]: a silent hemoglobin variant with a mutation within the heme pocket.

We report a new hemoglobin (Hb) variant, Hb Marineo [beta70(E14)Ala --> Val], found in three generations of a family from West Sicily. The mutation is due to a GCC --> GTC substitution at codon 70 of the beta-globin gene. To date, three mutations at codon 70 of the beta-globin gene have been described, presenting with hemolytic anemia. In our case, no anemia or other alteration of hematological indices were found. Cation exchange high performance liquid chromatography (HPLC) showed a peak in the P2 window (VARIANT I), while a peak was detected by VARIANT II HPLC in the P3 window. Reversed phase HPLC analysis showed an abnormal chain amounting to about 40% of the total beta chains.

Adult↗
PubMed2001

A rapid method for the identification and differentiation of Helicoverpa nucleopolyhedroviruses (NPV Baculoviridae) isolated from the environment.

A diagnostic method is described for the identification and differentiation of nucleopolyhedrovirus (NPV) pathogens of Helicoverpa species (Lepidoptera: Noctuidae) isolated from the environment. The method is based on the polymerase chain reaction (PCR) used in conjunction with restriction fragment length polymorphism (RFLP) analysis and comprises three parts. The first part describes procedures for obtaining PCR quality viral DNA from individual diseased H. armigera cadavers recovered during bioassay analyses of soil and other types of environmental sample. These procedures were modified from standard techniques used for the routine purification and dissolution of NPV polyhedra and provided an overall PCR success rate of 95% (n=60). The second part describes the design of several sets of PCR primers for generating DNA amplification products from closely and distantly related NPVs. These PCR primers were designed from published DNA sequence data and from randomly cloned genomic DNA fragments isolated from a reference H. armigera SNPV (HaSNPV) isolate. The final part of the method describes how specific PCR products when digested with specific restriction endonuclease enzymes, can be used to generate diagnostic DNA profiles (haplotypes) that can be used both to identify heterologous NPVs e.g. Autographa californica MNPV and related viruses, and to differentiate genotypic variants of Helicoverpa SNPV. In the latter case, only two PCR products and four restriction digests were required to differentiate a reference set of 10 Helicoverpa SNPV isolates known to differ 0.1--3.5% at the nucleotide level. The diagnostic method described below marks the second part of a two-phase quantitative-diagnostic protocol that is now being applied to a variety of ecological investigations. In particular, its application should lead to a significant improvement in our understanding of the distribution and population genetics of Helicoverpa SNPVs in the Australian environment, as well as providing a sound basis for the design of pre- and post-release monitoring systems for genetically enhanced bioinsecticides. It is also likely that this method can be adapted readily to the study of other insect pathogen associations important economically.

Animals↗