Intra- and interindividual epigenetic variation in human germ cells
James M Flanagan1, Violeta Popendikyte, Natalija Pozdniakovaite
1The Krembil Family Epigenetics Laboratory, Centre for Addiction and Mental Health, Toronto, ON, Canada.
American Journal of Human Genetics
|June 15, 2006
Summary
Human germline epigenetics reveals significant DNA methylation variability within and between individuals. This epigenetic individuality in sperm may impact inheritance and health outcomes, requiring further investigation into transgenerational transmission.
Area of Science:
- Human molecular genetics
- Epigenetics and genomics
Background:
- Epigenetics, a secondary inheritance system, is under-investigated in human biology.
- DNA methylation patterns in human germ cells are largely unknown.
Purpose of the Study:
- To comprehensively analyze DNA methylation variation in human male germlines.
- To investigate epigenetic differences within and between individuals' sperm cells.
Main Methods:
- Bisulphite sequencing of promoter regions in disease-associated genes (PSEN1/2, BRCA1/2, DM1, HD).
- Microarray-based epigenetic profiling using a 12,198-feature CpG island microarray.
- Analysis of DNA methylation variability in single-copy and repetitive elements.
Main Results:
- Significant DNA methylation variation detected within individual sperm cells and between different individuals.
- Microarray identified numerous methylation-variable positions, particularly in promoter CpG islands and pericentromeric satellites.
- Age-related DNA methylation changes observed in genes like EED, CTNNA2, CALM1, CDH13, and STMN2; allele-specific methylation found in CDH13.
Conclusions:
- Human germ cells exhibit substantial epigenetic variability.
- Further research is needed to understand the heritability of these epigenetic patterns and their influence on health and disease.
Related Concept Videos
03:17Inheritance of Chromatin Structures
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
02:32Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
01:37Epigenetic Regulation
Epigenetic changes alter the physical structure of the DNA without changing the genetic sequence and often regulate whether genes are turned on or off. This regulation ensures that each cell produces only proteins necessary for its function. For example, proteins that promote bone growth are not produced in muscle cells. Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
X-chromosome...
X-chromosome...
01:46Epigenetic Regulation
Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
01:46Epigenetic Regulation
Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.