Related Experiment Video
Updated: May 22, 2026

Determination of DNA Methylation of Imprinted Genes in Arabidopsis Endosperm
Published on: January 28, 2011
Pregnancy and the methyltransferase genotype independently influence the arsenic methylation phenotype
Renee M Gardner1, Karin Engström, Matteo Bottai
1Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Objectives:
The methyltransferase genotype and pregnancy both influence the arsenic metabolism phenotype, but it is unknown whether these factors interact, explaining the drastic changes in the efficiency of arsenic metabolism observed among pregnant women. The aim of this study was to evaluate the relative contribution of the methyltransferase genotype and pregnancy to the arsenic metabolism phenotype.
Methods:
We studied longitudinally the arsenic metabolite pattern in urine (at approximately gestational weeks 8, 14, and 30) of 303 women exposed to arsenic through drinking water and food in rural Bangladesh. Urinary arsenic metabolites were measured by high-performance liquid chromatography-inductively coupled plasma mass spectrometry. Data were available on genotypes for 16 polymorphisms, combined as haplotypes, in three methyltransferases: arsenic(+III)methyltransferase (AS3MT) and DNA-methyltransferases 1a and 3b (DNMT1a and DNMT3b). Changes in the arsenic metabolite pattern over time were evaluated by haplotype using logistic quantile regression.
Results:
All four AS3MT haplotypes and all three DNMT1a haplotypes significantly influenced the metabolite pattern in the pregnant women, with consistent effects of genotype over the entire course of pregnancy. No interaction was found between the haplotypes and pregnancy-related changes in the arsenic metabolism phenotype. DNMT3b haplotypes did not significantly influence the metabolite pattern. We observed a pregnancy-attributable decrease of 5.7% in the most risk-associated monomethylated metabolite, methylarsonic acid, whereas changes between 1.6 and 5.3% of methylarsonic acid could be attributed to haplotypes of AS3MT and DNMT1a.
Conclusion:
Independent of the genotype, the efficiency of arsenic methylation increased markedly over the course of pregnancy. The effect of pregnancy on the metabolite pattern during the observational period was greater than the effect of genotype.
More Related Videos
06:21Multi-Gene Single Nucleotide Polymorphism Detection in Gastric Cancer Based on Ion Semiconductor Sequencing Platform
Published on: May 10, 2024
03:19Modifying Levels of Maternal Dietary Folic Acid or Choline to Study the Impact of Deficiencies on Offspring Health Outcomes
Published on: June 28, 2024
Related Concept Videos
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Genomic Imprinting and Inheritance
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Phase II Reactions: Methylation Reactions
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...