Detect Restriction Fragment Length Polymorphisms Research Articles

PRRSV2 genetic diversity defined by RFLP patterns in the United States from 2007 to 2019.

The genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) increases over time. In 1998, restriction-fragment length polymorphism (RFLP) pattern analysis was introduced to differentiate PRRSV wild-type strains from VR2332, a reference strain from which a commercial vaccine (Ingelvac PRRS MLV) was derived. We have characterized here the PRRSV genetic diversity within selected RFLP families over time and U.S. geographic space, using available ISU-VDL data from 2007 to 2019. The 40,454 ORF5 sequences recovered corresponded to 228 distinct RFLPs. Four RFLPs [2-5-2 (21.2%), 1-7-4 (15.6%), 1-4-4 (11.8%), and 1-8-4 (9.9%)] represented 58.5% of all ORF5 sequences and were used for cluster analysis. Over time, there was increased detection of RFLPs 2-5-2, 1-7-4, 1-3-4, 1-3-2, and 1-12-4; decreased detection of 1-4-2, 1-18-4, 1-18-2, and 1-2-2; and different detection trends for 1-8-4, 1-4-4, 1-26-1, 1-22-2, and 1-2-4. An over-time cluster analysis revealed a single cluster for RFLP 2-5-2, supporting that sequences within RFLP 2-5-2 are still relatively conserved. For 1-7-4, 1-4-4, and 1-8-4, there were multiple clusters. State-wise cluster analysis demonstrated 4 main clusters for RFLP 1-7-4 and 1-8-4, and 6 for RFLP 1-4-4. For the other RFLPs, there was a significant genetic difference within them, particularly between states. RFLP typing is limited in its ability to discriminate among different strains of PRRSV. Understanding the magnitude of genetic divergence within RFLPs helps develop PRRSV regional control programs, placement, herd immunization strategies, and design of appropriate animal movements across borders to minimize the risk of PRRSV transmission.

Association of Per3 length polymorphism with susceptibility of Alzheimer disease (AD) in Chinese population

Objectives: The association of Per3 length polymorphism with susceptibility of Alzheimer Disease (AD) was examined in the present study. Methods: This study was constructed using the case-control method and investigated the association of Per3 length polymorphism with susceptibility of AD. Genotypes of APOE and Per3 length were determined by a PCR restriction fragment length polymorphism detection method. Results: In this study, we gathered 130 unrelated AD patients and 188 controls in performing an analysis the association of Per3 length polymorphism with susceptibility of AD. In the whole sample or APOE ε4 non-carriers, an increased prevalence of five repeat homozygotes of Per3 length in AD patients had significant higher than that in controls (in the whole sample: χ2 = 7.261,= 0.0176; in APOE ε4 non-carriers: χ2 = 6.086, p = 0.030). And, among APOE ε4 carriers, an increased prevalence of five repeat homozygotes of Per3 length in AD patients had also significant higher than that in controls (χ2 = 3.893, p = 0.0319). Conclusions: Among APOE ε4 non-carriers, five repeat homozygotes of Per3 length was associated with a high susceptibility of AD among APOE ε4 carriers and non-carriers.

The polymorphism of CLOCK gene rs4864548 A>G is associated with susceptibility of Alzheimer’s disease in Chinese population

The aim of this study was to investigate the correlation between polymorphism of circadian locomotor output cycle kaput (CLOCK) gene rs4864548 A/G and susceptibility of Alzheimer’s disease (AD). A total of 296 unrelated AD patients and 423 control subjects were enrolled in the case-control study. Genotypes of apolipoprotein E (APOE) and CLOCK gene rs4864548 A/G were determined by a Polymerase Chain Reaction (PCR) restriction fragment length polymorphism detection method. Our results showed that in the whole sample or APOE ε 4 non-carriers, prevalence of A carriers in CLOCK gene rs4864548 A/G in AD patients was remarkably higher than that in control subjects (in the whole sample: χ2 = 47.614, p < 0.0001; in APOE ε 4 non-carriers: χ2 = 22.493, p < 0.0001). However, among APOE ε 4 carriers, the difference in the prevalence of A carriers in CLOCK gene rs4864548 A/G between AD patients and controls was no statistically significant (χ2 = 0.669, p = 0.379). These findings demonstrate that A carriers in CLOCK gene rs 4864548 A/G were closely related to a high susceptibility of AD among APOE ε 4 non-carriers while the functional polymorphism of CLOCK gene rs4864548 A/G was not associated with the susceptibility of AD among APOE ε 4 carriers.

610 DEVELOPMENT OF A TEST FOR RCC BY DETECTION OF VHL MUTATIONS IN TISSUE AND FLUIDS OF PATIENTS WITH RENAL CELL CARCINOMA

You have accessJournal of UrologyKidney Cancer: Basic Research (IV)1 Apr 2013610 DEVELOPMENT OF A TEST FOR RCC BY DETECTION OF VHL MUTATIONS IN TISSUE AND FLUIDS OF PATIENTS WITH RENAL CELL CARCINOMA Shilpa Sreedharan, Rebecca S Arnold, Kimberly Kerley, Kristina B Mercer, Kerry Ressler, Viraj A Master, Kenneth Ogan, David L Roberts, John G Pattaras, and John A Petros Shilpa SreedharanShilpa Sreedharan Atlanta, GA More articles by this author , Rebecca S ArnoldRebecca S Arnold Atlanta, GA More articles by this author , Kimberly KerleyKimberly Kerley Atlanta, GA More articles by this author , Kristina B MercerKristina B Mercer Atlanta, GA More articles by this author , Kerry ResslerKerry Ressler Atlanta, GA More articles by this author , Viraj A MasterViraj A Master Atlanta, GA More articles by this author , Kenneth OganKenneth Ogan Atlanta, GA More articles by this author , David L RobertsDavid L Roberts Atlanta, GA More articles by this author , John G PattarasJohn G Pattaras Atlanta, GA More articles by this author , and John A PetrosJohn A Petros Atlanta, GA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.161AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Surgery is the only highly effective therapy for renal cell carcinoma (RCC) and there is no effective screening or blood test for RCC. Somatic changes in the von Hippel-Lindau gene (VHL) are found in approximately 80% of clear cell RCC. Cancer cells and/or DNA may be recovered from body fluids of patients with RCC in nearly every case. The objective of this research is to develop a blood and/or urine test for RCC based upon the detection of small amounts of circulating tumor DNA characterized by the somatic mutations in VHL. METHODS DNA from archived patient tissue and fluids was used to compile a panel of acquired VHL polymorphisms for use in a diagnostic urine or serum test identifying circulating RCC cells. The sensitivities of methods capable of such identification were contrasted to more easily detect mutations present in early stages of RCC at a time when they can be surgically cured. DNA from 50 archived renal cancer patient tissue, serum, and urine was purified, amplified, and sequenced using an ABI3100 DNA Sequencer. The mutations detected were confirmed with restriction fragment length polymorphism (RFLP), when possible. The sensitivity of RFLP was contrasted with Sequenom's© ability to detect minute amounts of mutated DNA in urine and serum via a single base extension reaction and mass spectrometry. RESULTS Sequencing of VHL revealed the presence of mutations which subsequently created alterations in restriction enzyme digestion. After analysis of the commonly mutated exon regions of VHL for 50 patients, 78% were found to have mutations. 17% of those mutations occurred in multiple patients. DNA from serum and/or urine from these patients was then examined for the identified mutations. 27% of patients had mutations detected in the DNA purified from their serum and/or urine. Contrasting the sensitivity of mutation detection via RFLP of body fluids versus detection via Sequenom indicated that Sequenom was able to identify mutations present in DNA as dilute as 0.05ng, compared to 12.5ng DNA required for RFLP detection. CONCLUSIONS A panel of the most highly observed VHL polymorphism DNA biomarkers is a potential diagnostic tool for the detection of early stage RCC. High-throughput identification methods of such mutations, such as mass spectrometry, have an increased sensitivity and specificity compared to PCR/RFLP analysis and would therefore better translate into clinical application. VHL mutations identified in DNA purified from patient urine or serum via RFLP and mass spectrometry support the feasibility of developing such a test. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e249-e250 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shilpa Sreedharan Atlanta, GA More articles by this author Rebecca S Arnold Atlanta, GA More articles by this author Kimberly Kerley Atlanta, GA More articles by this author Kristina B Mercer Atlanta, GA More articles by this author Kerry Ressler Atlanta, GA More articles by this author Viraj A Master Atlanta, GA More articles by this author Kenneth Ogan Atlanta, GA More articles by this author David L Roberts Atlanta, GA More articles by this author John G Pattaras Atlanta, GA More articles by this author John A Petros Atlanta, GA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Genetic association of crown rust resistance genePc68, storage protein loci, and resistance gene analogues in oats

Segregating F(3) families, derived from a cross between oat cultivar Swan and the putative single gene line PC68, were used to determine the association of seed storage protein loci and resistance gene analogues (RGAs) with the crown rust resistance gene Pc68. SDS-PAGE analysis detected three avenin loci, AveX, AveY, and AveZ, closely linked to Pc68. Their diagnostic alleles are linked in coupling to Pc68 and were also detected in three additional lines carrying Pc68. Another protein locus was linked in repulsion to Pc68. In complementary studies, three wheat RGA clones (W2, W4, and W10) detected restriction fragment length polymorphisms (RFLPs) between homozygous resistant and homozygous susceptible F(3) DNA bulks. Four oat homologues of W2 were cloned and sequenced. RFLPs detected with two of them were mapped using F(3) and F(4) populations. Clone 18 detected a locus, Orga2, linked in repulsion to Pc68. Clone 22 detected several RFLPs including Orga1 (the closest locus to Pc68) and three RGA loci (Orga22-2, Orga22-3, and Orga22-4) loosely linked to Pc68. The diagnostic RFLPs linked in coupling to Pc68 were detected by clone 22 in three additional oat lines carrying Pc68 and have potential utility in investigating and improving crown rust resistance of oat.

FSH dystrophy and a subtelomeric 4q haplotype: a new assay and associations with disease

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease associated with contraction of arrays of tandem 3.3-kb units (D4Z4) on subtelomeric 4q. Disease-linked arrays usually have fewer than 11 repeat...

Dynamics of the Emergence of a Human Cytomegalovirus UL97 Mutant Strain Conferring Ganciclovir Resistance in a Pediatric Stem-Cell Transplant Recipient

Stem-cell transplant recipients are at risk of developing ganciclovir-resistant human cytomegalovirus (HCMV) infection caused by mutations in the viral UL97 gene. Knowledge of the relative proportions of coexisting HCMV wild-type and mutant strains may contribute to a better understanding of the dynamics of in vivo mutant strain selection under ganciclovir. Currently, genotype resistance screening for UL97 is routinely performed by restriction fragment length polymorphism detection and sequencing. We present here the longitudinal course of a pediatric recipient of an allogeneic stem-cell transplant infected with a ganciclovir-resistant HCMV strain. EDTA-treated blood samples were analyzed longitudinally. The patient acquired a primary HCMV infection shortly before transplantation and reactivated the virus following allogeneic hematopoietic stem cell transplantation, thus receiving an intensive antiviral treatment schedule. Three different methods for UL97 mutation analysis, restriction fragment length polymorphism detection, sequencing, and a new, real-time PCR approach were performed. In conclusion, for our pediatric patient, during peak viral load, the UL97 wild-type strain predominates, while during clinical deterioration with low viral load, the predominant mutant strain persists.

Use of DNA polymorphisms of the apolipoprotein genes to study the role of genetic variation in the determination of serum lipid levels.

Cloned DNA probes for the apolipoprotein B (apoB) gene and the gene cluster for apoA-I/C-III/A-IV were used to detect restriction fragment length polymorphisms (RFLPs) at these two loci. Samples have been obtained from clinically well individuals, and the RFLP genotypes of each individual have been determined. The data show that at the locus for apoB, genetic variation associated with an RFLP detected by the enzyme XbaI (but not that associated with RFLPs detected by MspI or EcoRI) is involved in determining the normal levels of serum total cholesterol and low density lipoprotein (LDL) cholesterol. In our study, genetic variation associated with the XbaI RFLP accounts for 14% of the total phenotypic variance in cholesterol levels. Information from all three RFLPs can be used in conjunction to give a better definition of the underlying genetic variation. Data from a second study show that genetic variation in the apoA-I/C-III/A-IV gene cluster, associated with the PstI RFLP, is involved in determining the level of apoA-I and, to a lesser extent, the levels of high density lipoprotein (HDL). When genotypes from three RFLPs were used in conjunction as a haplotype, genetic variation in this gene cluster was shown to account for 16% of the phenotypic variance in apoA-I concentration and for 8% of the phenotypic variance in HDL concentration in our sample. These associations suggest that the isolation and sequencing of the apoB and the apoA-I/C-III/A-IV genes from different individuals will give useful information about how changes in the DNA sequence of these genes may lead to alterations in the levels of their respective apolipoproteins, in the level of the lipoproteins with which they are associated and, possibly, in the levels of lipids in the serum.

New evidence fromSinapis albaL. for ancestral triplication in a crucifer genome

We present clear evidence of ancestral genome triplication in Sinapis alba, a close relative of the cultivated Brassica species. Exceptionally high levels of heterozygosity in the parents of an F1 intercross permitted the mapping of an estimated 87% of all detected restriction fragment length polymorphism (RFLP) loci, with each RFLP probe typically detecting 2 or 3 loci. These duplicated loci were arranged in 8 triplicated homologous linkage blocks and 2 small, duplicated, homologous linkage blocks covering the majority of the S. alba genome. Several large-scale inversions and translocations appear to have rearranged the order of loci within homologous blocks. The role of successive polyploidization events on the evolution of crucifer species is discussed.

Chromosome allele loss in colorectal liver metastases and its association with clinical features.

Molecular genetic changes are better characterized in colorectal carcinoma than in other common adult tumours. Consistent allele losses, or loss of heterozygosity (LOH), on chromosomes 5q, 17p and 18q have been well established. These changes are associated with the prognosis of the disease. Little is known of such changes in liver metastases of colorectal origin. The extent of allelic loss and its association with clinical features were investigated in 19 patients with colorectal liver metastases by using 24 probes to detect restriction fragment length polymorphism. A high frequency of LOH on chromosomes 5q, 17p and 18q was found in these secondary tumours. No consistent loss has so far been shown in any other chromosome. The frequency of allele loss correlated significantly with prognostic features such as the number and size of liver secondaries (P < 0.005), metastasis to the lymph nodes (P < 0.01) and curative or palliative operation (P < 0.02).

Characterization of DNA markers isolated from the gynogenetic triploid ginbuna ( Carassius auratus langsdorfi) by representational difference analysis

Representational difference analysis (RDA) was carried out to isolate genetic markers for gynogenetic triploid ginbuna ( Carassius auratus langsdorfi) suitable for clarifying its genomic makeup. Four polymorphic DNA fragments were obtained by seven series of RDA, in which amplicons prepared from the diploid ginbuna or the goldfish ( C. a. auratus) as drivers were subtracted from those prepared from the triploid ginbuna as testers. These fragments detected presence- and absence-type in the amplicons prepared from C. auratus fishes. Hybridization analyses with each of these markers to genomic DNA revealed that these sequences were present in the DNA of all tested populations of C. auratus fishes, but were absent from the DNA of other cyprinid fishes. Thus, these markers could detect restriction fragment length polymorphisms among C. auratus fishes. Three out of four RDA markers were identified in the amplicons mainly from the triploid ginbuna and the goldfish. One remaining marker was shared between a clonal line of the triploid ginbuna and several individuals of the diploid ginbuna. These data provide additional evidence for the genomic contribution made by the ancestor(s) of the goldfish and the diploid ginbuna to the triploid hybrid ginbuna.

Utility of three restriction fragment length polymorphism probes for genotyping of the chicken major histocompatibility complex class IV region

Three chicken B-G cDNA probes (gene 8.5, bg28, and bg32.1) were used to detect restriction fragment length polymorphisms (RFLP) in the chicken MHC class IV (B-G). By using inbred and selected chicken lines with different B haplotypes identified by hemagglutination, we identified B haplotypes (B2, B9, B11, B12, B15, B19, B21, B31, and B32) by RFLP using the three probes following digestion of genomic DNA with four restriction endonucleases (BglII, EcoRI, HaeIII, and PvuII). The GSP inbred line, previously shown to contain B-F21 by the use of a monoclonal antibody, did not contain B-G21, based on RFLP tests, whereas line N had B-F21 and B-G21. Consequently, the RFLP typing with the clone of B-G cDNA was able to determine the B haplotype in more detail than typing by hemagglutination. In inbred and selected lines, three B-G cDNA are useful DNA probes for RFLP to identify B genotypes. Two families of chickens with segregating B haplotypes were analyzed by RFLP using these probes; however, identification of the B genotype by this method was difficult in the randomly bred population. Genotypic comparisons of RFLP with gene 8.5 and BglII and bg 28 as probes and digestion by the endonucleases EcoRI, HaeIII, and PvuII between the parents and their offspring were generally compatible within the expectations of Mendelian inheritance.

The Identity and Parentage of the Variety Known in California as Petite Sirah

DNA marker analysis was used to determine the varietal identity of Petite Sirah in public collections and commercial vineyards in California. Twenty-one vines analyzed from public collections at the University of California at Davis included accessions labeled Petite Sirah, Durif, Syrah and Serine. Fifty-three vines from 26 private Petite Sirah vineyards in four California counties were also analyzed. Several accessions each of Durif, Peloursin, and Syrah obtained from Montpellier, France and an accession of Pinot noir from the University of California at Davis were used as controls for varietal identification. Samples were analyzed with four to eight simple sequence repeat (SSR) DNA markers. Some samples were first analyzed with four DNA probes to detect restriction fragment length polymorphisms (RFLPs). Davis accessions labeled Petite Sirah were found to include vines that we determined to be Durif, Peloursin, Syrah, and Pinot noir. Accessions labeled Durif9 included vines identical to Durif and Peloursin. The Syrah accessions were identical to the Syrah controls. The Serine accession was found to be Pinot noir. Forty-nine of the 53 Petite Sirah vines from private vineyards were identical to Durif. Four vines, from three vineyards in two counties, were Peloursin. Comparison of the SSR genotypes of Durif and Peloursin indicates that Durif is probably a seedling of Peloursin as reported and cannot be a selection of Peloursin (as also reported). The other parent of Durif is most probably Syrah. SSR genotypes of Durif, Peloursin, and Syrah at 25 loci are consistent with this relationship and likelihood analysis of SSR allele frequencies supports the relationship with a very high degree of probability.

Establishment of framework P1 clones for map-based cloning and genome sequencing: direct RFLP mapping of large clones.

Large insert capacity, clone stability and convenient propagation in Escherichia coli have made bacterial artificial chromosome and phage P1 vector-based libraries the first choice for large-scale sequencing projects, and these libraries have also proven useful for chromosome walking. The application of these libraries for either purpose is greatly facilitated by the establishment of a set of framework clones distributed across the genome. Using a P1-based library of Arabidopsis thaliana with genomic inserts of 70-90kb (Liu, Y.-G., Mitsukawa, N., Vazquez-Tello, A., Whittier, R.F., 1995. Generation of a high-quality P1 library of Arabidopsis suitable for chromosome walking. Plant J. 7, 351-358), we have now established such a set of framework clones. To date, such clones have usually been identified by hybridization to smaller, previously mapped clones that detect restriction fragment length polymorphisms (RFLPs). In order to establish framework clones more efficiently, we refined protocols for P1 clone DNA isolation and RFLP detection in order to employ whole P1 clones directly as probes. This strategy enabled a very high rate of RFLP detection, and obviated the need to screen the P1 library with smaller RFLP probes. Altogether 95 clones were mapped providing a framework into which further clones can be integrated by physical overlap.

Codominant PCR-based markers for Pinus taeda developed from mapped cDNA clones

We report a strategy for developing codominant PCR-based genetic markers by using sequenced cDNA clones from loblolly pine (Pinus taeda L.). These clones were previously used as probes for detecting restriction fragment length polymorphisms (RFLPs) to generate linkage maps. After assessing the complexity of banding patterns from Southern blots, we selected clones representing relatively simple gene families, and then determined nucleotide sequences for about 200 bp at each end of the cDNA inserts. Specific PCR primers were designed to amplify samples of genomic DNA derived from two loblolly pine mapping populations. Polymorphisms were detected after digesting the amplified DNA fragments with a battery of restriction endonucleases, and most polymorphisms were inherited in a Mendelian fashion. These newly identified genetic markers are codominant and relatively simple to use. By assaying DNA from individuals used to construct RFLP maps, we show that most of these markers map to the same position as the RFLP loci detected using their corresponding cDNAs as probes, implying that these markers have been converted from RFLP to PCR-based methods. These PCR-based markers will be useful for genome mapping and population genetics.

Simple and Reliable Factor V Genotyping by PNA-Mediated PCR Clamping

Resistance to activated protein C (APC resistance) is the most common cause of thrombophilia and linked to a single point mutation in the factor V gene (G-->A transition at nucleotide 1691). In the past, several PCR based methods have been proposed to determine the allelostatus of individual patients from small amounts of blood DNA including PCR followed by restriction fragment length polymorphism detection (PCR-RFLP), PCR using sequence-specific primers (PCR-SSP) and oligonucleotide ligation assay (OLA). Here, we present a novel approach based on the method of peptide nucleic acid(PNA)-mediated PCR clamping which is extremely sensitive to base pair mismatches. If PNAs specific for the two allelic variants are applied separately in each case a clear discrimination between a heterozygous or homozygous normal or homozygous Factor V Leiden status is possible and no further confirmation step is required. In a prospective study, 60 patients with suspected venous thrombosis events were tested and compared to the conventional PCR-RFLP technique. The concordance between both methods was 100%. PNA-based factor V genotyping, therefore, should be considered for large scale screening of those patients considered to be at risk for deep venous thrombosis.

Molecular identification of sympatric chromosomal forms of Anopheles gambiae and further evidence of their reproductive isolation.

Three chromosomal forms of Anopheles gambiae s.s., designated as Bamako, Mopti and Savanna, were studied for diagnostic PCR assays based on the analysis of the X-linked ribosomal DNA (rDNA). The study was performed on a 1.3 kb fragment containing part of the 28S coding region and part of the intergenic spacer region. The amplified material was cut with fourteen restriction enzymes to detect Restriction Fragment Length Polymorphisms (RFLPs). The enzymes Tru9I and HhaI produced patterns of DNA bands which differentiated Mopti from Savanna and Bamako; moreover, a distinct 'hybrid' pattern was recognized in the F1 female progeny from the cross of Mopti with either one of the other two chromosomal forms. The diagnostic significance of the PCR-RFLP assay was verified on 203 karyotyped females from field samples collected in two villages in Mali and one village in Burkina Faso. Agreement was observed between the chromosomal and the molecular identifications. No 'hybrid' molecular patterns were detected even among carriers of rare heterokaryotypes hypothetically produced by crosses between Mopti and Savanna. The results confirm previous observations indicating barriers to gene flow within An. gambiae s.s. and supporting the specific status of the taxonomic units proposed on cytogenetic ground.

RFLP Detection of 2n Pollen Formation by First and Second Division Restitution in Perennial Ryegrass

Unreduced gametes can be used to transfer desirable traits from parent to polyploid offspring. Codominant restriction fragment length polymorphism (RFLP) markers were applied to determine the mechanism of 2n pollen formation in diploid (2n = 2x = 14) Lolium perenne L. Sixty heterologous probes were randomly chosen from a Festuca arundinacea Schreb. PstI‐genomic DNA library. A total of 30 and 33 heterozygous allelic loci were detected in two genotypes of parental L. perenne, respectively, based on segregation of RFLP loci in 13 triploid (3x) and two tetraploid (4x) hybrids, produced in 1993, between diploid L. perenne and tetraploid F. mairei St. Yves. Approximately 30 and 83% of the heterozygosity was transmitted by 2n pollen from L. perenne into two tetraploid hybrids, respectively. Both meiotic first division restitution (FDR) and second division restitution (SDR) occurred in 2n pollen formation in L. perenne. Omission of the second meiotic division (OS) and fusion of adjacent polar nuclei (FA) were found during microsporogenesis. These two mechanisms were supposedly responsible for forming 2n gametes by SDR and FDR, respectively. Formation of 2n pollen in diploid L. perenne could facilitate efficient transfer of germplasm from diploid to higher ploidy levels in Lolium and Festuca.

Nucleotide polymorphism, effective population size, and dispersal distances in the yellow baboons (Papio hamadryas cynocephalus) of Mikumi National Park, Tanzania.

We investigated genetic variability and population structure in a natural population of yellow baboons (Papio hamadryas cynocephalus) from Mikumi National Park, Tanzania. The amount of nuclear DNA polymorphism in a random sample of animals from four social groups was estimated by using Southern blotting to detect restriction fragment length polymorphisms in five nuclear autosomal loci. The average nucleotide heterozygosity was estimated to be 0.0033. This level of DNA polymorphism is higher than available estimates for human populations, but is consistent with protein and DNA sequence data from other nonhuman primates. The observed level of genetic variability suggests that the inbreeding effective population size of the Mikumi baboons is approximately 14,000. Predictions regarding the distribution of male dispersal distance are developed using Wright's isolation by distance model. The results of these analyses, while derived from genetic methods, are consistent with and provide additional information for behavioral and demographic descriptions of baboon population dynamics. © 1996 Wiley-Liss, Inc.

Association of the NAD(P)H-bispecific nitrate reductase structural gene with the Nar7 locus in barley

The NADH-specific and NAD(P)H-bispecific nitrate reductase genes from barley have been cloned and sequenced. To determine if the Nar7 locus encodes the NAD(P)H-bispecific nitrate reductase structural gene, a cross was made between a wild-type cultivar, Morex (Nar7 Nar7), and Az70 (nar7w nar7w), a mutant from the cultivar Steptoe that is deficient in NAD(P)H-bispecific nitrate reductase activity. A probe specific to the NAD(P)H-bispecific nitrate reductase structural gene detected restriction fragment length polymorphism between the parents. This probe was used to classify selected F2 progeny for restriction fragment length genotype. All the NAD(P)H nitrate reductase deficient F2 progeny (24/101) possessed the Az70 restriction fragment genotype. The absence of recombination between the NAD(P)H-bispecific nitrate reductase deficient genotype and the NAD(P)H-bispecific nitrate reductase restriction fragment length genotype indicates that the two traits are closely associated in inheritance and that Nar7 is probably the NAD(P)H-bispecific nitrate reductase structural gene.