Amy Gene Research Articles

Glycemic Response after Starch Consumption in Relation to Salivary Amylase Activity and Copy-number Variation of AMY1 Gene

Salivary amylase activity is partially determined by genetic factors and is possibly related with postprandial plasma glucose levels. The aim of this study is to evaluate the association of salivary amylase activity with plasma glucose and insulin levels after consumption of a gelatinized starchy model food (80% amylopectin; 70% gelatinization), as well as to assess the influence of the salivary amylase gene (AMY1) copy-number variation in amylase activity and concentration. Our results show a strong and significant relation between copy-number variation of AMY1 gene measured through qPCR with salivary amylase concentration, with an enhanced correlation with amylase activity when corrected by salivary flow (r = 0.83, P-value = 0.003). Subjects with high salivary amylase activity tend to have a higher early increase in plasma insulin concentration and a lower glycemic response after starch ingestion compared to subjects with low salivary amylase activity, although these observations did not achieve statistical significance (r = 0.41; P-value = 0.23). In conclusion, we found a strong association between copy-number of AMY1 gene with salivary amylase activity and concentration. However, we did not find evidences for a major role of salivary amylase activity on glycemic response after starch consumption.

Overexpression of salivary-type amylase reduces the sensitivity to bortezomib in multiple myeloma cells.

Amylase-producing myeloma exhibits refractoriness to chemotherapy and a dismal prognosis. In this study, we established a human myeloma cell line, 8226/AMY1, in which a lentivirally transfected AMY1 gene was stably expressed and explored its biological characteristics. 8226/AMY1 showed a survival advantage over mock control when treated with dexamethasone, bortezomib, and lenalidomide in vitro partly through inhibition of apoptosis induced by these reagents. In a xenograft murine model, 8226/AMY1 showed rapid tumor growth and reduced sensitivity to bortezomib compared with mock. A microarray gene expression analysis identified TCL1A, which functions as a coactivator of the cell survival kinase Akt, differentially up-regulated in 8226/AMY1. The expression of phosphorylated Akt was increased in the 8226/AMY1 cells following bortezomib treatment, but not in the mock cells. In addition, treatment with perifosine, an inhibitor of Akt phosphorylation, enhanced the anti-myeloma effect of bortezomib in the 8226/AMY1 cells. Our data suggest that amylase-producing myeloma reduced the sensitivity to bortezomib in vitro and in vivo, and the up-regulation of TCL1A may influence the drug susceptibility of 8226/AMY1 via the phosphorylation of Akt. These findings provide clues for developing treatment approaches for not only amylase-producing myeloma, but also relapsed and refractory myelomas.

The role of digestive factors in determining glycemic response in a multiethnic Asian population

There are wide inter-individual differences in glycemic response (GR). We aimed to examine key digestive parameters that influence inter-individual and ethnic differences in GR in healthy Asian individuals. Seventy-five healthy male subjects (25 Chinese, 25 Malays, and 25 Asian-Indians) were served equivalent available carbohydrate amounts (50g) of jasmine rice (JR) and basmati rice (BR) on separate occasions. Postprandial blood glucose concentrations were measured at fasting (-5 and 0min) and at 15- to 30-min interval over 180min. Mastication parameters (number of chews per mouth and chewing time per mouthful), saliva α-amylase activity, AMY1 gene copy numbers and gastric emptying rate were measured to investigate their relationships with GR. The GR for jasmine rice was significantly higher than for basmati rice (P<0.001). The median number of AMY1 gene copies was 6, with a range of 2-15. There was a significant positive relationship between AMY1 copy number and α-amylase activity (P=0.002). There were no significant ethnic differences in GR. For both rice varieties, the number of chews per mouthful was positively associated with the GR (JR, P=0.011; BR, P=0.005), while chewing time per mouthful showed a negative association (JR, P=0.039; BR, P=0.016). Ethnicity, salivary α-amylase activity, particle size distribution, gastric emptying rate and AMY1 gene copy numbers were not significant contributors to GR (P>0.05). Mastication parameters contribute significantly to GR. Eating slowly and having larger food boluses before swallowing (less chewing), both potentially modifiable, may be beneficial in glycemic control.

Cloning, enhanced expression and characterization of an α-amylase gene from a wild strain in B. subtilis WB800

A Bacillus strain with high productivity of α-amylase isolated from a starch farm was identified as Bacillus amyloliquefaciens. The α-amylase encoding gene amy1 was cloned into pMD18-T vector and amplified in E. coli DH5α. Shuttle vector pP43MNX was reconstructed to obtain vector pP43X for heterologous expression of the α-amylase in B. subtilis WB800. Recombinant enzyme was sufficiently purified by precipitation, gel filtration and anion exchange with a specific activity of 5566U/mg. The α-amylase sequence contains an open reading frame of 1545bp, which encodes a protein of 514 amino acid residues with a predicted molecular mass of 58.4kDa. The enzyme exhibited maximal activity at pH 6.0 and 60°C. Catalytic efficiency of the recombinant α-amylase was inhibited by Hg2+, Pb2+ and Cu2+, but stimulated by Li+, Mn2+ and Ca2+. The purified enzyme showed decreased activity toward detergents (SDS, Tween 20 and Triton X-100). Compared with production by the wild strain, there was a 1.48-fold increase in the productivity of α-amylase in recombinant B. subtilis WB800.

Association between salivary amylase (AMY1) gene copy numbers and insulin resistance in asymptomatic Korean men.

Salivary amylase gene (AMY1) copy number variations (CNVs) correlate directly with salivary amylase activity and serum amylase levels. Previously, individuals with high AMY1 CNVs exhibited low postprandial glucose levels and postprandial early insulin surge, suggesting that high AMY1 gene copy numbers may play a role in lowering the risk of insulin resistance. We verified the relationship between AMY1 CNVs and homeostatic model assessment-insulin resistance (HOMA-IR) in a cohort of 1257 Korean men aged 20-65 years who visited two medical centres for regular health check-ups, and in subgroups of current smokers and regular alcohol drinkers. Individuals with fasting plasma glucose levels > 10.0 mmol/l, HbA1c ≥ 64 mmol/mol (8.0%) or who used oral hypoglycaemic agents or insulin were excluded. AMY1 CNVs correlated negatively with HOMA-IR even after adjusting for covariates (e.g. BMI, systolic blood pressure, triacylglycerol, alcohol consumption, smoking and physical activity). When the participants were divided according to current smoking and alcohol consumption habits, negative correlations between AMY1 CNVs and HOMA-IR were more evident among non-smokers and regular drinkers and were non-significant among smokers and non-regular drinkers. Low AMY1 CNVs correlated with high insulin resistance in asymptomatic Korean men, and such a relationship presented differently according to the status of smoking and alcohol consumption.

Influences of AMY1 gene copy number and protein expression on salivary alpha-amylase activity before and after citric acid stimulation in splenic asthenia children

ObjectivesTo compare the correlations between salivary alpha-amylase (sAA) activity and amylase, alpha 1 (salivary) gene (AMY1) copy number or its gene expression between splenic asthenia and healthy children, and investigate the reasons of attenuated sAA activity ratio before and after citric acid stimulation in splenic asthenia children. MethodsSaliva samples from 20 splenic asthenia children and 29 healthy children were collected before and after citric acid stimulation. AMY1 copy number, salivary alpha-amylase (sAA) activity, and total sAA and glycosylated sAA contents were determined, and their correlations were analyzed. ResultsAlthough splenic asthenia and healthy children had no differences in AMY1 copy number, splenic asthenia children had positive correlations between AMY1 copy number and sAA activity before or after citric acid stimulation. Splenic asthenia children had a higher sAA glycosylated proportion ratio and glycosylated sAA content ratio, while their total sAA content ratio and sAA activity ratio were lower compared with healthy children. The glycosylated sAA content ratio was higher than the total sAA content ratio in both groups. Splenic asthenia and healthy children had positive correlations between total sAA or glycosylated sAA content and sAA activity. However, the role played by glycosylated sAA content in sAA activity in healthy children increased after citric acid stimulation, while it decreased in splenic asthenia children. ConclusionGenetic factors like AMY1 copy number variations, and more importantly, sAA glycosylation abnormalities leading to attenuated sAA activity after citric acid stimulation, which were the main reasons of the attenuated sAA activity ratio in splenic asthenia children compared with healthy children.

Obesity, starch digestion and amylase: association between copy number variants at human salivary (AMY1) and pancreatic (AMY2) amylase genes.

The human salivary amylase genes display extensive copy number variation (CNV), and recent work has implicated this variation in adaptation to starch-rich diets, and in association with body mass index. In this work, we use paralogue ratio tests, microsatellite analysis, read depth and fibre-FISH to demonstrate that human amylase CNV is not a smooth continuum, but is instead partitioned into distinct haplotype classes. There is a fundamental structural distinction between haplotypes containing odd or even numbers of AMY1 gene units, in turn coupled to CNV in pancreatic amylase genes AMY2A and AMY2B. Most haplotypes have one copy each of AMY2A and AMY2B and contain an odd number of copies of AMY1; consequently, most individuals have an even total number of AMY1. In contrast, haplotypes carrying an even number of AMY1 genes have rearrangements leading to CNVs of AMY2A/AMY2B. Read-depth and experimental data show that different populations harbour different proportions of these basic haplotype classes. In Europeans, the copy numbers of AMY1 and AMY2A are correlated, so that phenotypic associations caused by variation in pancreatic amylase copy number could be detected indirectly as weak association with AMY1 copy number. We show that the quantitative polymerase chain reaction (qPCR) assay previously applied to the high-throughput measurement of AMY1 copy number is less accurate than the measures we use and that qPCR data in other studies have been further compromised by systematic miscalibration. Our results uncover new patterns in human amylase variation and imply a potential role for AMY2 CNV in functional associations.

Attenuated acute salivary α-amylase responses to gustatory stimulation with citric acid in thin children.

Salivary α-amylase (sAA) is responsible for the 'pre-digestion' of starch in the oral cavity and accounts for up to 50% of salivary protein in human saliva. An accumulating body of literature suggests that sAA is of nutritional importance; however, it is still not clear how sAA is related to individual's nutritional status. Although copy number variations (CNV) of the salivary amylase gene (AMY1) are associated with variation in sAA levels, a significant amount of sAA variation is not explained by AMY1 CNV. To measure sAA responses to gustatory stimulation with citric acid, we used sAA ratio (the ratio of stimulated sAA levels to those of resting sAA) and investigated acute sAA responses to citric acid in children with normal (Normal-BMI, n 22) and low (Low-BMI, n 21) BMI. The AMY1 gene copy number was determined by quantitative PCR. We, for the first time, demonstrated attenuated acute sAA responses (decreased sAA ratio) to gustatory stimulation in Low-BMI (thinness grade 3) children compared with the Normal-BMI children, which suggest that sAA responses to gustatory stimulation may be of nutritional importance. However, child's nutritional status was not directly related to their resting or stimulated sAA levels, and it was not associated with AMY1 gene copy number. Finally, AMY1 CNV might influence, but did not eventually determine, sAA levels in children.

Physiological significance of higher amy1 gene copy number on postprandial responses to starchy foods in caucasian adults

Physiological significance of higher amy1 gene copy number on postprandial responses to starchy foods in caucasian adults

Beneficial effect of a high number of copies of salivary amylase AMY1 gene on obesity risk in Mexican children.

Childhood obesity is a major public health problem in Mexico, affecting one in every three children. Genome-wide association studies identified genetic variants associated with childhood obesity, but a large missing heritability remains to be elucidated. We have recently shown a strong association between a highly polymorphic copy number variant encompassing the salivary amylase gene (AMY1 also known as AMY1A) and obesity in European and Asian adults. In the present study, we aimed to evaluate the association between AMY1 copy number and obesity in Mexican children. We evaluated the number of AMY1 copies in 597 Mexican children (293 obese children and 304 normal weight controls) through highly sensitive digital PCR. The effect of AMY1 copy number on obesity status was assessed using a logistic regression model adjusted for age and sex. We identified a marked effect of AMY1 copy number on reduced risk of obesity (OR per estimated copy 0.84, with the number of copies ranging from one to 16 in this population; p = 4.25 × 10(-6)). The global association between AMY1 copy number and reduced risk of obesity seemed to be mostly driven by the contribution of the highest AMY1 copy number. Strikingly, all children with >10 AMY1 copies were normal weight controls. Salivary amylase initiates the digestion of dietary starch, which is highly consumed in Mexico. Our current study suggests putative benefits of high number of AMY1 copies (and related production of salivary amylase) on energy metabolism in Mexican children.

Characterization of maltotriose production by hydrolyzing of soluble starch with α-amylase from Microbulbifer thermotolerans DAU221.

A maltotriose-producing α-amylase, AmyA, from a newly isolated bacterial strain Microbulbifer thermotolerans DAU221 was purified and characterized in the heterologous host, Escherichia coli, using the pCold I vector. The amyA gene encoded a 761-residue protein composed of a 33 amino acid secretion signal peptide. The purified α-amylase with a molecular mass of 80 kDa, approximately, shared a sequence motif characteristic of the glycoside hydrolase family 13. The enzyme was optimally active, at 50 °C in sodium phosphate buffer (pH 6.0), by the traditional one factor-at-a-time method. But the optimal conditions of time, temperature, and pH for production of maltotriose from soluble starch were 1.76 h, 44.95 °C, and pH 6.35 by response surface methodology, respectively. Maltotriose, as the major enzyme reaction product, was analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The enzyme was found to be inhibited by the addition of 10 mM Cu(2+), Fe(3+), Hg(2+), Zn(2+), and EDTA, but exhibited extreme stability toward hexane. The K m and V max values for the hydrolysis of soluble starch were 1.08 mg/mL and 1.736 mmol maltotriose/mg protein/min, respectively.

Adaptive evolution of α‐amylase genes in wild barley (Hordeum spontaneum) on micro and macro scales

AbstractAlpha‐amylases play essential roles in germination, and the malting and brewing processes, by hydrolyzing starch granules present in the endosperm of barley. Hordeum spontaneum C. Koch, the progenitor of cultivated barley that harbors rich genetic diversity, was collected from seven different environments. To investigate the influence of microclimatic ecological divergence on α‐amylase, single nucleotide polymorphisms (SNPs) in amy genes from these populations were determined. A total of 16 and 17 SNPs were detected in the coding sequences of amy1 and amy2, respectively, from the seven wild barley populations. Among these SNPs, three in amy1‐2 and nine in amy2‐2 were significantly associated with ecological factors. The genetic divergence of amy sequences was significantly different among the populations. Natural microclimatic selection was apparently the major evolutionary driving force causing interslope divergence and adaptive evolution of these genes. The genetic variation in amy1‐2 and amy2‐2 was at least partly ecologically determined in these populations, representing adaptive patterns generated by natural selection. The SNPs were apparently generated by natural selection in climatic environmental patterns at both the micro (“Evolution Canyon”) and macro (across Israel, Galilee, and Negev) scales.

English

The use of fertilizer is pivotal to ensure soil fertility. Green fertilizers have many advantages and bio-molecules generated in a bacterial cell that can be used as green fertilizer. To produce bio-molecules from a bacterial cell, a bacterium was isolated that uses natural starch as sole carbon source. The organism was grown in presence of various natural starchy materials. The organism was partially identified as Bacillus sp. The optimum conditions for growth of the strain were: temperature of 37.0°C and pH 7.0. However, it grows well even above 55.0°C. The optimum conditions for degradation of various starchy substrates using extra-cellular amylase of the strain were studied. The optimum pH was 4.0 for soluble starch whereas it was pH 5.0 for other substrates and temperature was 17.0°C for soluble starch and 37.0°C for others. Prolongation of time of incubation, velocity of enzyme reaction, and optimum concentration of various metal ions for amylase activity was also studied using optimum assay conditions. Molecular cloning and expression of amy gene of the strain was done in Escherichia coli DH5α. The host cell harboring the recombinant plasmid was grown in the presence of potato starch and incubated for many days to obtained cellular lysate and the liquid biomass might be used as bio-fertilizer. Key words: Amylolytic bacteria, amylase, bio-molecules, bio-fertilizer, single cell fertilizer.

Construction of a Food-Grade Expression Vector Based on pMG36e by Using an α-Galactosidase Gene as a Selectable Marker

Construction of a food-grade expression vector for application to lactic acid bacteria (LAB) is of importance for dairy fermentation system. An α-galactosidase (aga) gene encoding an enzyme degrading melibiose was amplified by PCR from the plasmid pRAF800 of Lactococcus lactis NZ9000. The aga gene was introduced into pMG36e to substitute the primary antibiotic selectable marker of pMG36e, resulting in construction of a new food-grade expression vector pMG36-aga. To testify the expression efficiency of exogenous gene in pMG36-aga, a 1.5 kb long α-amylase (amy) gene from Bacillus licheniformis was cloned by PCR and introduced into the plasmid pMG36-aga. The resultant plasimd pMG36-aga-amy was transformed into L. lactis ML23 by electroporation. The positive clones were selected with the medium containing melibiose as the sole carbon source. The selection efficiency of aga was 8.71×103 CFU with a standard deviation of 9.1×102 CFU µg−1 DNA of pMG36-aga. Furthermore, the SDS-PAGE analysis showed that the pMG36-aga-amy expressed a 56.4 kDa protein which was the same as the putative molecular weight of α-amylase. The starch plate assay also indicated that L. lactis ML23 displayed high activity of α-amylase by expressing of amy gene of pMG36-aga-amy.

Determination of expression and activity of genes involved in starch metabolism in Lactobacillus plantarum A6 during fermentation of a cereal-based gruel

Traditional fermented gruels prepared from cereals are widely used for complementary feeding of young children in Africa and usually have a low energy density. The amylase activity of some lactic acid bacteria (LAB) helps increase the energy content of gruels through partial hydrolysis of starch, thus enabling the incorporation of more starchy material while conserving the desired semi-liquid consistency for young children. Even if this ability is mainly related to the production of alpha-amylase (E.C. 3.2.1.1), in a recent molecular screening, genes coding for enzymes involved in starch metabolism were detected in the efficient amylolytic LAB Lactobacillus plantarum A6: alpha-glucosidase (E.C. 3.2.1.20), neopullulanase (E.C. 3.2.1.135), amylopectin phosphorylase (E.C. 2.4.1.1) and maltose phosphorylase (E.C. 2.4.1.8). The objective of this study was to investigate the expression of these genes in a model of starchy fermented food made from pearl millet (Pennisetum glaucum). Transcriptional and enzymatic analyses were performed during the 18-h fermentation period. Liquefaction was mainly caused by an extracellular alpha amylase encoded by the amyA gene specific to the A6 strain among L. plantarum species and found in both Lactobacillus amylovorus and Lactobacillus manihotivorans. The second most active enzyme was neopullulanase. Other starch metabolizing enzymes were less often detected. The dynamic detection of transcripts of gene during starch fermentation in pearl millet porridge suggests that the set of genes we investigated was not expressed continuously but transiently.

A markerless gene replacement method for B. amyloliquefaciens LL3 and its use in genome reduction and improvement of poly-γ-glutamic acid production.

We herein adapted a markerless gene replacement method by combining a temperature-sensitive plasmid pKSV7 with a counterselectable marker, the upp gene encoding uracil phosphoribosyltransferase (UPRTase), for the poly-γ-glutamic acid (γ-PGA)-producing strain Bacillus amyloliquefaciens LL3. Deletion of the upp gene conferred LL3 5-fluorouracil (5-FU) resistance. Sensitivity to 5-FU was restored when LL3 Δupp was transformed with pKSV7-based deletion plasmid which carries a functional allele of the upp gene of Bacillus subtilis 168. These observations allowed us to adapt a two-step plasmid integration and excision strategy to perform markerless deletion of genes of interest. Deletion plasmid harboring a mutant allele of the target gene was first integrated in the genome by culturing cells under nonpermissive conditions for pKSV7 replication. Single-crossover recombinants were then grown without antibiotics to aid the second recombinational event. 5-FU was used to select for double-crossover recombinants with plasmid evicted from the chromosome. The resulting recombinants either harbored the wild-type or mutated allele of the target gene and could be identified by PCR and DNA sequencing. Using this method, we successively removed the amyA gene and a 47-kb fragment of the bae cluster from the genome of LL3, with higher efficiency compared with previous reports. We also investigated the effects of a transcriptional regulator, RocR, on γ-PGA production and cell growth. Specific γ-PGA production of the rocR mutant was increased by 1.9-fold, which represents a new way to improve γ-PGA production.

Molecular characterization of high pI α-amylase and its expression QTL analysis in synthetic wheat RILs

α-Amylase plays a key role in seed germination. Activity of α-amylase determines levels of starch degradation, seed germination, and pre-harvest sprouting (PHS), which is a serious problem in wheat production. In this study, we isolated and characterized high PI amylase coding genes from the wheat cultivar Chuanmai32 (PHS susceptible) and the synthetic wheat SHW-L1 (PHS resistant). amy1 gene sequences were 1,459 a long and contained three exons and two introns. Phylogenetic analysis revealed that homologous genes obtained from the two accessions were extremely conserved and belonged to barley AMY2-1 subgroup. Six nucleotide substitutions were detected in the exon regions between the two amy1 genes. The amino acid substitutions Lys364/Arg364 and Arg366/Trp366 occurred in the C-terminal region, which is present in the anti β-sheet three-dimensional structure of AMY1. Expression profiling of amy1 indicated that mRNA transcript accumulation began at a late stage of grain development. amy1 transcript accumulation in Chuanmai32 was 4.32- and 18.36-fold higher than observed in SHW-L1 at DPA25 and DPA30, respectively. Two significant expression quantitative trait loci (eQTLs) on chromosome 1BS and one on 3DS were characterized by expression analysis of amy1 transcripts and genetic analysis of SHW-L1/Chuanmai32-derived recombinant inbred lines. The genes that encoded high PI amylase were located near the centromere on chromosomes 6AL/6BL/6DL. These results suggest that these eQTL regions may provide candidate genes that play potential roles in regulating PHS through effects on amy1 expression.

Variation in Salivary and Pancreatic Alpha-Amylase Genes in Italian Horse Breeds

The dietary demand of the modern horse relies on high-cereal feeding and limited forage compared with natural grazing conditions, predisposing the horse to several important diseases. Salivary and pancreatic alpha-amylases (coded by AMY1 and AMY2 genes, respectively) play a crucial role in carbohydrate digestion in nonruminants, but little is known about these 2 genes in the horse. Aim of this work has been to distinguish genomic sequences of horse AMY1 and AMY2 genes and to analyze any polymorphisms in breeds historically characterized by marked differences in nutritional management. A single nucleotide polymorphism detection was performed and 7 novel single nucleotide polymorphisms were found. Three single nucleotide polymorphisms are in exons and were genotyped in 112 horses belonging to 6 breeds. One single nucleotide polymorphism in AMY1 gene distinguished Haflinger and the Italian native Murgese from the other breeds, whereas both the single nucleotide polymorphisms in AMY2 gene showed different allelic frequencies in Friesian compared with the other breeds. These differences are confirmed by quite high fixation index (Fst) values for these 2 nonsynonymous single nucleotide polymorphisms. These preliminary results highlight marked divergences in allele frequencies of AMY1 and AMY2 genes, involved in starch digestion, between horse breeds characterized by different histories of selection, thus providing first indications of possible relations between genetics and nutritional management.

Lactase persistence and augmented salivary alpha-amylase gene copy numbers might have been selected by the combined toxic effects of gluten and (food born) pathogens

Various positively selected adaptations to new nutrients have been identified. Lactase persistence is among the best known, conferring the ability for drinking milk at post weaning age. An augmented number of amylase gene (AMY1) copies, giving rise to higher salivary amylase activity, has been implicated in the consumption of starch-rich foods. Higher AMY1 copy numbers have been demonstrated in populations with recent histories of starchy-rich diets. It is however questionable whether the resulting polymorphisms have exerted positive selection only by providing easily available sources of macro and micronutrients. Humans have explored new environments more than any other animal. Novel environments challenge the host, but especially its immune system with new climatic conditions, food and especially pathogens. With the advent of the agricultural revolution and the concurrent domestication of cattle came new pathogens. We contend that specific new food ingredients (e.g., gluten) and novel pathogens drove selection for lactase persistence and higher AMY gene copy numbers. Both adaptations provide ample glucose for activating the sodium glucose-dependent co-transporter 1 (SGLT1), which is the principal glucose, sodium and water transporter in the gastro-intestinal tract. Their rapid uptake confers protection against potentially lethal dehydration, hyponatremia and ultimately multiple organ failure. Oral rehydration therapy aims at SGLT1 activity and is the current treatment of choice for chronic diarrhoea and vomiting. We hypothesize that lifelong lactase activity and rapid starch digestion should be looked at as the evolutionary covalent of oral rehydration therapy.

A Prospective Screening of Gene Copy Number Variation in Brazilian Admixed Population Sample

Copy number variants (CNVs) represent an important source of variation in the human genome. Some CNVS embedded genes are differently distributed among the human population groups. Therefore, it is important to understand the distribution of CNV within and between populations, especially in those with admixed ancestry, such as the Brazilians. The aim of the study was to investigate the variability of a set of CNV-embedded genes in a sample of the Brazilian population. The CNV-embedded genes were chosen based on data showing that they have differential copy variation distribution between African and Europeans. Four genes (POLR2J4, PCDHB13, NPEPPS and AMY1) were investigated by qPCR in a sample of 96 Brazilians, previously classified by genetic ancestry. The gene AMY1 showed a variable copy numbers in the range of 1 to 8 copies whereas NPEPPS ranged from 1 to 5 copies. A low variability was identified for the POLR2J4 and PCDHB13 genes, showing 2 copies in frequency of 0.875 and 0.917, respectively. Genetic ancestry was not correlated to the number of copies of the AMY1and NPEPPS genes. The results provided an overview of the corresponding frequency of gene copy number variation in a sample of the Brazilian population, serving as reference for further genetic population studies, which may correlate these polymorphisms with other phenotypic features.