Presence Of Restriction Site Research Articles

Genome-Wide Comparative Analysis of BZR1 Transcription Factor in Zea mays

The BR-responsive genes are then regulated by BRASSINAZOLERESISTANT (BZR) Transcription Factors (TFs). As BRs possess numerous stress-resistant functions, BZR TFs also show activities of stress-resistance along with other developmental functions. Up to 88% similarity of protein sequences has been observed between BZR1 and BZR2 genes. Many positive roles of BZR TFs have been revealed by many studies in positively regulating the BR signal transduction in rice and maize family, but there is a very limited research is available on the BZR gene family of Zea mays. The aim of this study is to perform a wide-genome analysis of BZR1 transcription factor in Zea mays so that regulatory role of BZR TFs in BR-induced signaling pathway can be revealed. Gene structure analysis revealed the information about exons and introns. Phylogenetic analysis was done to identify the maximum likelihood among different families of BZR genes. Restriction analysis provided the information about the presence of restriction sites in Zea mays genome.

Immunohistochemical evaluation of vitamin D receptor (VDR) expression in cutaneous melanoma tissues and four VDR gene polymorphisms.

Objective: Vitamin D receptor (VDR) mediates vitamin D activity. We examined whether VDR expression in excised melanoma tissues is associated with VDR gene (VDR) polymorphisms. Methods: We evaluated VDR protein expression (by monoclonal antibody immunostaining), melanoma characteristics, and carriage of VDR-FokI-rs2228570 (C>T),VDR-BsmI-rs1544410 (G>A),VDR-ApaI-rs7975232 (T>G), andVDR-TaqI-rs731236 (T>C) polymorphisms (by restriction fragment length polymorphism). Absence or presence of restriction site was denoted by a capital or lower letter, respectively: " F” and " f” for FokI, " B” and " b” for BsmI, " A” and " a” for ApaI, and " T” and " t” for TaqI endonuclease. Seventy-four Italian cutaneous primary melanomas (52.1±12.7 years old) were studied; 51.4% were stage I, 21.6% stage II, 13.5% stage III, and 13.5% stage IV melanomas. VDR expression was categorized as follows: 100% positivevs. <100%; over the median 20% (high VDR expression) vs. ≤20% (low VDR expression); absence vs. presence of VDR-expressing cells. Results: Stage I melanomas, Breslow thickness of <1.00 mm, level II Clark invasion, Aa heterozygous genotype, and AaTT combined genotype were more frequent in melanomas with high vs. low VDR expression. Combined genotypes BbAA, bbAa, AATt, BbAATt, and bbAaTT were more frequent in 100% vs. <100% VDR-expressing cells. Combined genotype AATT was more frequent in melanomas lacking VDR expression (odds ratio=14.5; P=0.025). VDR expression was not associated with metastasis, ulceration, mitosis >1, regression, tumor-infiltrating lymphocytes, tumoral infiltration of vascular tissues, additional skin and non-skin cancers, and melanoma familiarity. Conclusions: We highlighted that VDR polymorphisms can affect VDR expression in excised melanoma cells. Low VDR expression in AATT carriers is a new finding that merits further study. VDR expression possibly poses implications for vitamin D supplementation against melanoma. VDR expression and VDR genotype may become precise medicinal tools for melanoma in the future.

Chromosome Banding in Crustacea. I. Karyotype, Ag-NORs, C Banding and Treatment with EcoRI, PstI and KpnI Restriction Endonucleases in Artemia franciscana

Karyotypic characteristics of the microcrustacean Artemia franciscana Kellog 1906, introduced to the salt lakes on the northeastern coast of Brazil in the 1970s, were investigated by conventional staining, C banding, restriction endonucleases (EcoRI, PstI and KpnI) and Ag-NORs. The karyotype consisted of 42 chromosomes and secondary constrictions were observed on some pairs. Large heterochromatic blocks were found distributed in the telomere portion of most of the chromosomes. Digestion with PstI and KpnI showed a similar pattern to that obtained by C banding. Preparations treated with EcoRI revealed intense action in the heterochromatic regions indicating the presence of restriction sites. Multiple Ag-NORs were shown associated to heterochromatic blocks. These data presented here no identified modifications that might have occurred after the geographic isolation of this stock and examine the evolutionary modifications in the karyotype of this group. Keywords : Chromosome banding; brine shrimp; crustacean cytogenetics.

Screening and characterization of resistance to succinate dehydrogenase inhibitors in Alternaria solani

Field isolates of Alternaria solani, which causes early blight of potato in Idaho, USA were evaluated in vitro for their sensitivity towards the succinate dehydrogenase inhibitor (SDHI) fungicides boscalid, fluopyram and penthiopyrad. A total of 20 isolates were collected from foliar‐infected tissue in 2009, 26 in 2010 and 49 in 2011. Fungicide sensitivity was tested using the spiral‐gradient end point dilution method. The frequency of boscalid‐resistant isolates (&gt;50% relative growth when using a spiral dilution gradient starting at 507 mg L−1) drastically increased over the duration of this study (15% in 2009, 62% in 2010 and 80% in 2011). Increasing resistance to fluopyram and penthiopyrad was observed. However, cross‐resistance was only observed between boscalid and penthiopyrad. The target site of this fungicide class is the succinate dehydrogenase (SDH) enzyme complex, which is vital for fungal respiration. Sequence analysis of the SDH complex revealed mutations in the subunits B and D that were correlated with the emergence of boscalid resistance in potato fields in Idaho. In particular, H277R and H133R were identified in SDH subunits B and D, respectively. The presence of restriction sites in the gene sequences allowed the development of a rapid PCR‐RFLP method to assess boscalid sensitivity in A. solani populations.

Development of microsatellite molecular markers and genetic diversity in Hevea Braziliensis

Background The rubber tree [Hevea Braziliensis (Willd. ex Adr. De Juss.) Muell-Arg.] is native from the Amazon region which has great economic importance for being the largest source of natural rubber in the world. Although Brazil is the center of origin and genetic diversity of this culture, the country is currently responsible for only 1% of the world production. Besides offering optimal weather conditions for crop development, the Amazon rainforest region is also favorable to the development of the fungus known as SALB (South American leaf blight), which causes the disease-of-leaves. Leaves fall sharply reducing the production of latex, limiting the production of rubber in this region. Thus breeding programs are seeking for clones which are resistant to this fungus and with high production in escape regions, which provide stress conditions such as low temperatures, high altitude, wind and other diseases [1]. The rubber tree is perennial and requires about 30 years to obtain an improved variety, starting from the controlled pollination of a clone to the final recommendation. Molecular markers such as microsatellites (Simple Sequence Repeats, SSRs) are an important tool for diversity studies and potentially to assist breeding programs. This study aimed to develop an enriched microsatellite library for H. Braziliensis, characterize these developed microsatellite markers and test the transferability of these markers to six other species of the genus Hevea. Material and methods For this study we used 36 accessions of H. Braziliensis donated by the Agronomy Institute of Campinas and one accession of each of six other species of genus Hevea (H. nitida, H.pauciflora (2), H.camargoana, H.guianensis, H. rigidifolia andH. benthamiana) provided by Embrapa. Genomic DNA samples were extracted from lyophilized leaf tissues using a modified CTAB method [2]. Trinucleotide and dinucleotide enriched genomic libraries for H. Braziliensis were constructed. The DNA samples were digested with AFAI and enriched using (CT)8 and (GT)8 biotinylated microsatellite probes for the dinucleotide library and (ATC)8 and (CCT)8 for the trinucleotide library. The clones obtained were sequenced and the sequences were evaluated with the Microsat program, which removes parts of the vector and the adapters and verifies the presence of restriction site within the sequence. After this step, the sequences were aligned and edited using the program SeqMan (DNAStar Inc.), which also allows analyzing the redundancy of the library. The identification of microsatellites was performed using a research tool SSRs SSRIT – “The Simple Sequence Repeat Identification Tool” avaiable at Gramene [http:// www.gramene.org]and primers complementary to sequences flaking the microsatellites were designed by Primer Select Program (DNAStar Inc) and Primer 3. Amplification tests were made from a temperature gradient to know the annealing temperature and the products were evaluated and resolved on 3% agarose gels stained with ethidium bromide and in denaturing 6% polyacrylamide and silver stained [3]. The loci were characterized on the number of alleles per locus, allele frequency and the Polymorph Information Content (PIC). It was also made analysis of ancestry for de accessions of H. Braziliensis using the program Structure v 2.3.3 [4]. * Correspondence: camila.mantello@gmail.com Molecular Genetic Analysis Laboratory Molecular Biology Center and Genetic Engineering (CBMEG), UNICAMP, Campinas, Sao Paulo, 13083-875, Brazil Full list of author information is available at the end of the article Mantello et al. BMC Proceedings 2011, 5(Suppl 7):P11 http://www.biomedcentral.com/1753-6561/5/S7/P11

Seamless cloning and domain swapping of synthetic and complex DNA

The use of synthetic DNA can avoid problems that are sometimes encountered with conventional molecular biology techniques using DNA with high GC content, strong secondary structures, or repeat sequences. However, very complex DNA may still resist PCR and synthesis of DNA from oligonucleotides. In the method described here, separately synthesized DNA segments were seamlessly joined independently of the presence of restriction sites in the target DNA. This method allowed the reconstruction of complex DNA by concatenation of easily synthesized segments and permitted repeated swapping of segments, from a few nucleotides to large fragments of complex DNA for phenotypic analysis.

Inverse PCR-based site-directed mutagenesis of nucleotide sequences coding for carbohydrate-binding fragments of legume lectins

A new method of site-directed mutagenesis was developed to allow manipulation with extended plasmid-cloned gene fragments irrespective of their position and the presence of restriction sites. The method was used to obtain chimeric constructs encoding a Pisum sativum lectin with the native carbohydrate-binding region replaced by its counterpart from other legumes. The method can be used in plasmid construction to clone a coding gene fragment under the control of a promoter in a certain reading frame.

Association between vitamin D receptor Fokl polymorphism and serum parathyroid hormone level in patients with chronic renal failure

We investigated the relationship between vitamin D receptor (VDR) start codon polymorphism and serum levels of PTH, calcidiol, and calcium in 64 Spanish patients with chronic renal failure (CRF). An exon 2 fragment of the VDR gene was amplified by PCR, and cleaved with the restriction enzyme FokI. The alleles were identified according to the digestion pattern obtained as F (absence of restriction site) and f (presence of restriction site). Genotype frequencies in the patient population were 54.7% FF, 28.1% Ff and 17.2% ff, vs 46.7% FF, 43.3% Ff and 10% ff in a healthy control population. The difference between the two populations was statistically significant (p<0.01). Within the patient population, mean serum PTH level in the FF group was significantly higher (159.77+/-25.69 pg/ml) than in both the Ff and ff groups (106.67+/-19.07 and 77.55+/-15.85 pg/ml, respectively; p<0.05). However there were no significant differences in serum levels of calcidiol or calcium among genotypes. These results suggest that FokI polymorphisms of the VDR gene may determine parathyroid response in CRF patients.

Mitochondrial DNA in the hybrid zone between Mus musculus musculus and Mus musculus domesticus: a comparison of two transects

We studied mtDNA introgression across the contact zone between Mus musculus musculus and M. m. domesticus in two independent transects in the Czech Republic and Bavaria, Germany. A total of 1270 mice from 98 localities in the Czech transect and 456 mice from 41 localities in the Bavarian transect were examined for presence or absence of a BamHI restriction site in the mt-Ndl gene. Using this simple mtDNA marker, variants that belonged to the M. m. domesticus lineage (presence of restriction site) could be unequivocally distinguished from those belonging to the M. m. musculus lineage (absence of restriction site). The extent of introgression of mtDNA, three autosomal allozymes and the X chromosome was compared. The introgression of X markers was more limited than was that of the allozymes and mtDNA. In the Czech transect, the centre for the mtDNA dine was shifted about 3.6 km to the west relative to the X chromosome dine, with asymmetric introgression from M. m. musculus to M. m. domesticus. Interestingly, in the Bavarian transect, the centre of the mtDNA dine was shifted about 10.9 km to the east relative to the X chromosome dine, with asymmetric introgression from M. m. domesticus to M. m. musculus, opposite in direction to that observed in the Czech transect.

Detection of species-specific genetic markers in farm animals by RFLP analysis of cytochrome b gene

RFLP analysis was used on several meat sources to identify the species. It might be important to evaluate a method to identify different meat species. We tested Buffalo, Cattle, Goat and Sheep to enforce labeling regulation in the authentication of each of them. In this study, the presence of restriction sites on the polymerase chain reaction (PCR) products has been used for the specific identification of the four different meat species. The cytochrome b encoding gene (359 bp) as a part of the mt-DNA was amplified. The digestion of the PCR products using Anil and Hae III gave specific restriction profiles that allowed a direct identification of farm animal species in raw and heat-treated meat samples. The results showed that RFLP analysis provided with a rapid and effective method to detect meat species and could be easily used for meat identification and authentication.

Omiga: a PC-based sequence analysis tool.

Computer-based sequence analysis, notation, and manipulation are a necessity for all molecular biologists working with any but the most simple DNA sequences. As sequence data become increasingly available, tools that can be used to manipulate and annotate individual sequences and sequence elements will become an even more vital implement in the molecular biologist's arsenal. The Omiga DNA and Protein Sequence Analysis Software tool, version 2.0 provides an effective and comprehensive tool for the analysis of both nucleic acid and protein sequences that runs on a standard PC available in every molecular biology laboratory. Omiga allows the import of sequences in several common formats. Upon importing sequences and assigning them to various projects, Omiga allows the user to produce, analyze, and edit sequence alignments. Sequences may also be queried for the presence of restriction sites, sequence motifs, and other sequence features, all of which can be added into the notations accompanying each sequence. This newest version of Omiga also allows for sequencing and polymerase chain reaction (PCR) primer prediction, a functionality missing in earlier versions. Finally, Omiga allows rapid searches for putative coding regions, and Basic Local Alignment Search Tool (BLAST) queries against public databases at the National Center for Biotechnology Information (NCBI).

Association of serum low-density lipoprotein metabolism with oestrogen receptor gene polymorphisms in healthy children

The aim of this study was to reveal the association of serum lipid and apolipoprotein levels with oestrogen receptor (ER) Xba I and Pvu II polymorphisms in 102 healthy Japanese school children (56M, 46F) aged 10-15 y. Each genotype of the genomic DNA extracted from peripheral leukocytes was determined using polymerase chain reaction and digestion with Xba I or Pvu II. The genotypes were coded as either X1 or X2 (Xba I) and P1 or P2 (Pvu II), when XI, P1 signified the absence of and X2, P2 the presence of restriction sites. The fasting serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride and apolipoproteins A1, B and E were measured. In the Xba I polymorphism, LDL cholesterol, apolipoprotein B levels of the XI/XI genotype were significantly higher than those of the others. The other lipid and apolipoprotein levels were not significantly different among the three genotypes. In the Pvu II polymorphism, there were no significant differences in serum lipids and lipoproteins among the three genotypes. This study reveals that Xba I polymorphisms are related to LDL metabolism. These findings support previous reports that the LDL-lowering effects of oestrogen occur through the ER (alpha) pathway. The Xba I polymorphism may be one of the genetic factors in the control of LDL metabolism.

Itai-itai disease is not associated with polymorphisms of the estrogen receptor alpha gene.

Itai-itai (or ouch-ouch) disease is a syndrome accompanied by bone mineral disorders, and which may be related to oral cadmium exposure. Itai-itai predominantly affects postmenopausal women with a history of multiple childbirths. Recently, it has been reported that polymorphisms of the estrogen receptor alpha (ERalpha) gene are associated with postmenopausal reduction of bone mineral density in Japanese women. However, estrogen receptors have never been studied in itai-itai disease. In this study, we examined the genotypic distributions of PvuII and XbaI restriction fragment length polymorphisms (RFLPs) of the ERalpha gene in patients with itai-itai disease and compared them with those of control subjects. The RFLPs are represented here as Pp (PvuII) and Xx (XbaI); the capital and small letters signify the absence and presence of restriction sites, respectively. The genotypic distributions of the patient group were: PP, 14.8%; Pp, 55.6%; pp, 29.6%; XX, 7.4%; Xx, 29.6%; and xx, 63.0%. These distributions were similar to those observed for the control groups, hence no pattern of genotypic distribution was observed that could be related to itai-itai disease. We conclude that RFLPs of the ERalpha gene may not be associated with itai-itai disease.

Association of vitamin D receptor gene polymorphism with multiple sclerosis in Japanese.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active form of vitamin D, exerts an immunosuppressive effect and can completely prevent experimental autoimmune encephalomyelitis (EAE). 1,25(OH)2D3 exerts most of its actions only after it has bound to its specific nuclear receptors. To investigate the possible role of vitamin D receptor gene (VDRG) polymorphism in susceptibility to or disease-modulation of MS, we evaluated 77 Japanese patients with 'conventional' MS and 95 controls. A VDRG allelic polymorphism was assessed by Bsm1 endonuclease restriction after specific PCR amplification. Genotypic polymorphism was clearly defined as BB (absence of restriction site on both alleles), bb (presence of restriction site on both alleles), or Bb (heterozygous). We found overexpression of the b allele (92.9 vs. 84.2%: P=0.0138) and homozygote bb (85.7 vs. 71.6%; P=0.0263) in MS patients compared with controls. The results indicate for the first time an association of MS with VDRG polymorphism, which may be involved in pathogenesis of MS, or in the linkage disequilibrium of VDRG to another pathogenic gene loci. The role of VDR gene polymorphism should be further studied in other populations, and the distribution of other polymorphism, such as Apa I, Taq I, should be also analyzed to confirm another susceptibility gene for MS and to obtain more adequate strategies for treatment of MS.

Estrogen receptor gene polymorphism and bone mineral density at the lumbar spine of pre- and postmenopausal women

In order to analyze the role of the estrogen receptor (ER) gene allelic polymorphisms on bone mineral density (BMD), 173 pre- and postmenopausal women were divided into four groups according to their menstrual status (group A: premenopausal women; group B: late premenopausal women; group C: postmenopausal women who had menopause for 5 years or less; and group D: postmenopausal women who had menopause for more than 5 years), and the relationship between ER gene polymorphism and lumbar spine BMD, the percent annual change in BMD and biochemical markers were studied. The restriction fragment length polymorphism (RFLPs) were represented as Xx (XbaI) and Pp (PvuII), with upper case and lower case letters signifying the absence or presence of restriction sites, respectively. In group A, the Xx genotype had significantly higher BMD ( p < 0.01) than the xx genotype, but the difference was lost in groups B, C, and D. Because the percent annual change in BMD of group A was 0.052% and was not statistically different among genotypes, it is suggested that RFLP by Xba I is closely linked with peak bone mass that was attained during the subject's late thirties. In group B, serum N-region osteocalcin (N-OC) levels and the percent annual change in BMD showed a significantly larger increase than that of group A, indicating postmenopausal bone loss had commenced. Because the N-OC level of the Xx genotype was significantly higher than that of the xx genotype ( p < 0.05), and the percent annual change in BMD of the Xx genotype showed a tendency to increase ( p = 0.072), it is suggested that the high BMD of the Xx genotype is rapidly lost during menopausal transition. There were no significant relationships between RFLP and BMD in groups C and D, and between RFLP by PvuII and BMD. The present study suggests that the Xx genotype is involved in accretion of BMD during young adulthood, but the effect was lost during menstrual transition.

Vitamin D receptor gene polymorphisms are not related to bone turnover, rate of bone loss, and bone mass in postmenopausal women: the OFELY Study.

Vitamin D receptor (VDR) gene polymorphisms have been reported to account for most of the well established genetic influence on bone mineral density (BMD). However, discordant studies have been published and it is still not clear whether VDR genotypes influence bone mass accretion and/or postmenopausal bone loss. In this study, we analyzed VDR gene polymorphisms, i.e., that of BsmI, ApaI, and TaqI restriction enzymes in 268 untreated postmenopausal women 1-26 years postmenopausal. There were 37 BBAA homozygote (absence of BsmI and ApaI restriction sites on both alleles), 55 bbaa homozygote (presence of restriction sites on both alleles), and 176 heterozygotes. At baseline, women between the three genotypes did not differ significantly in age, years since menopause, body mass index (BMI), nor dietary calcium intake. We found no relationship between VDR genotypes and bone turnover assessed by three serum markers of bone formation and three urinary bone resorption markers, nor with BMD measured at the spine, hip, forearm, and whole body by dual-energy X-ray absorptiometry (DXA). Rates of bone loss assessed by repeated DXA measurements over 2 years were highly significant (p = 0.02-0.0001) at all skeletal sites except for the lumbar spine but did not differ between genotypes at any sites either before or after adjustment for potential confounding factors such as years since menopause, BMI, calcium intake, serum 25 hydroxyvitamin D levels, and baseline BMD. When we restricted the analysis to early postmenopausal women, within 10 years of menopause (n = 128), lumbar spine bone loss became significant, but no significant difference between VDR genotypes in the rate of bone loss measured at any site was found. We conclude that VDR genotypes are not predictive of bone turnover, rate of postmenopausal bone loss, and bone mass in either early or late postmenopausal women. In a subgroup of women with a low calcium intake (below 600 mg/day), we also found no significant differences between genotypes in BMD and the rate of bone loss measured at any site, although the sample size (n = 64) may be too small to detect small differences. In conclusion, these data, along with the absence of relationships between VDR gene polymorphisms and peak bone mass that we recently reported, suggest that the determination of VDR genotypes is probably not a useful clinical test for the risk assessment of osteoporosis.

Genetic Diversity inSclerotium(Athelia)rolfsiiand Related Species

Pairings among 119 isolates of Sclerotium rolfsii, 11 of S. delphinii, and two of S. coffeicola on potato-dextrose agar to establish mycelial compatibility groups (MCGs) revealed 49, 3, and 2 MCGs, respectively, in a worldwide collection. Within an MCG, isolates were often from the same host and geographical area ; however, widely diverse isolates also were grouped within the same MCG. The host of origin of the isolate was not correlated with the MCG except in S. delphinii. Many MCGs were comprised of only one isolate. Variation in nuclear rDNA [internal transcribed spacer (ITS) regions] was examined following restriction enzyme digests. Restriction fragment length polymorphisms (RFLPs) were obtained with AluI, HpaII, RsaI, and MboI and could distinguish amongst the three Sclerotium spp. and three Athelia spp. (an outgroup). Combined banding patterns for the four enzymes were used to characterize intraspecific variation in the three Sclerotium spp. There were 12 subspecific groupings in S. rolfsii, one in S. delphinii, and two in S. coffeicola; some of these groupings correlated with their MCG. However, isolates within an MCG could show different ITS-RFLP patterns and certain patterns were also dispersed among different MCGs. The total sum of digested fragment sizes exceeded the undigested polymerase chain reaction product in several S. rolfsii isolates. This length discrepancy was not due to artifacts or incomplete digestion and, therefore, must have resulted from variation among rDNA copies in the presence of restriction sites. Furthermore, segregation of two MboI restriction patterns in the ITS region among 29 single-basidiospore strains, derived from four parental field isolates of S. rolfsii with one pattern, suggested the presence of two distinct rDNA types in the field isolates. The rDNA types may reflect a heterokaryotic nuclear condition in field isolates of S. rolfsii. Restriction maps and phylogenetic analyses supported a close affinity of the three Sclerotium spp., which may be more appropriately designated as subspecific varieties of S. rolfsii.

A simple and efficient method for the oligodeoxyribonucleotide-directed mutagenesis of double-stranded plasmid DNA

A method for the oligodeoxyribonucleotide-directed mutagenesis of double-stranded DNA without the necessity for phenotypic selection is described. Plasmids denatured with alkali and purified by adsorption to and elution from nitrocellulose have single-stranded regions where primers can hybridize and serve as templates for a T7 DNA polymerase-catalyzed synthesis of complementary mutant DNA strands. When this procedure was carried out such that the original nonmutant strand contained uracil [method of Kunkel, Proc. Natl. Acad. Sci. USA 82(1985)488–492], mutation frequencies of between 30% and 40% were obtained. The technique has been used to generate mutant genes in plasmids of a wide variety of sizes. The largest plasmid manipulated and successfully mutagenized was 22 kb. The method is rapid and efficient and is not dependent upon either f1 phage vectors or the presence of restriction sites in the vicinity of the sequence targeted for mutation.

DNA Polymorphisms of the Apolipoprotein AI/CIII/ AIV Gene Cluster Influence Plasma Cholesterol and Triglyceride Levels in the Mayans of the Yucat&amp;aacute;n Peninsula, Mexico

The purpose of this work was to examine the influence of apolipoprotein gene variation on plasma lipid levels in a population of Mayan Indians of the Yucatán Peninsula, Mexico. Four restriction enzymes: XmnI, PstI, SstI, and PvuII, were used to detect restriction fragment length polymorphisms (RFLP) within the region of the apolipoprotein AI/CIII/AIV gene cluster. The frequencies of these polymorphisms in this Mayan population were similar to those reported for other Amerindian populations, but differed widely from those reported for Caucasian populations. The XmnI and SstI RFLPs were informative for association studies in this population, and we analyzed their influence on the quantitative variation of plasma cholesterol and triglycerides. Using a nonparametric analysis of variance, it is shown that the presence of the XmnI restriction site had a significant effect in lowering plasma cholesterol, whereas the presence of the restriction site for SstI had a significant effect in raising plasma triglycerides. Consequently, genetic indicators of both low and high risk for lipid-related diseases, such as atherosclerosis and coronary heart disease, seem to be present within the same gene region in this Mayan population.

Restriction site polymorphism at the LPA (Lp(a) apoliprotein; apoliprotein(a)) locus

A restriction site polymorphism in the Lp(a) apolipoprotein gene (the LPA gene) is reported. The basis for the polymorphism is presence or absence of an MspI restriction site that appears to be 3' to the last kringle IV structure of the gene. The "1" gene (presence of the restriction site) has a frequency of 0.316 and the "2" gene (absence of the restriction site) has a frequency of 0.684. Both members of each of 67 monozygotic (MZ) twin pairs had the same genotype and there was Mendelian segregation of the DNA variants in 40 families with a total of 75 children. There was a lower proportion of people with genotype 1-1 in the top quartile than in the 3 bottom quartiles of the population distribution of Lp(a) lipoprotein levels but the difference did not reach statistical significance.