epigenetics Flashcards
epigenetics
1) epi = on, upon, beyond, or above
2) epigenetics is something acting upon the genone
- a group of acquired and transgenerational dynamic molecular mechanisms that are affected by environment and act directly on genome to regulate gene expression
epigenetic research
1 )study heritable changes in gene function without change in sequences
- methylation and chromatin structure
2) genome
- cannot do anything without software
3) epigenome
- when where and how to work (software bugs = disease susceptible)
genes code for
1) 20,000 proteins
2) 3 billion bases of DNA
- protein coding is 1%
- 99% is noncoding
3) mutations can lead to diseases or traits
4 )most disease mutations occur outside of genes on DNA
- if they are combined the wrong way, can lead to mutations
- most mutations are not in genes, they are in the “switches”
epigenetic modification
1) DNA methylation
2) methyl groups added to promoters
- stop gene from being seen, switched off
genome gives rise to many cell types
1) each cell contains the entire genetic code, but they differentiate and specialize
2) epigenetics seeks to understand how biology is governed by how genes are read
- gene activity
genome encodes 2 layers of information
1) DNA helix
2) epigenetic code for development and maintenance of the genome
- DNA methylation
- histone protein acetylation in nucleosomes
- microRNA alterations
environment and genetic regulation
1) environment can up and down regulate expression
2) macroscopic
- diet, smoking ,inflammation, age
3) microscopic
4) nanoscale
epigenetic molecular mechanisms
1) affecting chromatin condensation
- DNA methylation
- Histone protein
- forming heterochromatin
2) preventing protein production directly
- non-coding RNA
3) epigenetic acts on coding AND noncoding regions of DNA
genetic imprinting
1) either the paternally or maternally inherited gene is repressed and only the other is transcribed
- most AD genes in mammalian are biallelic, but some are expressed with only one paternal allele
2) maternally derived genes are growth limiting, and paternally are growth enhancing
3) DNA methylation is responsible for the reproduction of imprinting in all daughter cells
cancer
1 )genome wide global hypomethylation and gene specific hypermethylation
2) histone hypoacetylation is implicated in silencing of tumor suppressor genes => uncontrolled growth
methylation and human behavior
1) nurture can adjust DNA methylation patterns, altering genetic expression and phenotype
2) ex. abused people have higher levels of hypermethylation of rRNA and fewer ribosomes for protein production
periodontalogy
1) proinflammatory cytokines are dependent of epigenetics
- smoking
- nutrition
- bacteria
2) periodontitis can reactivate HIV-1 expression through epigenetic mediators
orthodontics
1) changes in bone or cartilage occurring ins response to signals from other tissues
2) postnatal growth and response to clinical treatment is controlled by extrinsic factors through gene expression
2) molecular kits to diagnose growth related problems
cleft lip and palate
1) genetic risk interacts with environmental covariants
- nutrition and lifestyle are modifying susceptibility genes
2) triggers to susceptibility genes
enamel development and defects
1) DNA methylation on enamel protein amelogenin on X and Y is a factor in enamel developmental defect
behavioral management problems
1) transgenerational transmission of fear at epigenetic levels
agouti gene
1) pregnant mouse and fetal origin of adult diseases susceptibility
2) change the likelihood of obtaining agouti obese animal on bases of nutrients that were given to mother during pregnancy
- methyl group turning on and off
- methyl donors (genistein) => more normal coat
- more BPA (endocrine disruptor) => more yellow coat
- both => reversal of effect and Distribution is normal
human diseases and epigenetics
1) mutation in mother than could be transferred to newborn
2) environmental intervention
- methyl donor so that gene can be methylated
3 )extrapolation to prevention of adult diseases
- mutations can be silences
insufficient folate levels
1) cause congenital anomality
- delayed or less efficient proliferation of cells in growing tissue
- abnormal methylation of DNA interfering with cell differentiation
- abnormal methylation of lipids and peptides interfering with cellular function
buffer hypothesis
1) environmental toxins interact with genes in a gene
2) gene network buffers their toxic influences
3) susceptibility genes in gene network decrease its buffering capacity
4) improved lifestyle of mother can increase buffering capacity of the mother embryo system
