Define epigenetics
Changes in gene expression that occur without changes in DNA sequence, how we can use the same genome and get so many different cells!
What are some characteristics of epigenetics?
1. stable, non-transient changes in expression
2. Can result in activation or repression of genes
3. Transmitted across generations (cellular and sometimes inherited)
What are the mechanisms of epigenetics (2)
1. DNA packaging-bulk activation/inact.
2. X chromosome inactivation
How does DNA packaging work?
methylation of DNA causes tighter packing (DNA off). Also histone modification via acetylation (turns DNA on) can help loosen the DNA from packaging
What is the histone code hypothesis?
the postr-translational modifications of histones, alone or in combo, function to specific and distinct DNA-templated programs
Where does the methylation of DNA occur on the code?
CpG primarily, which inhibits transcription. Some methylation patterns are gender specific (imprinting), must be faithfully copied each time DNA is replicated
How does X chromosome inactvation work?
Each X chromsome starts (in women) transcribing Xist RNA, which is going to coat the outer surface of that chromosome. The RNA coating will pack the chromosome very tightly. Th first one to oat the chromosme entirely, will be the chromosome that is inacti
How is skewed X inactivation determined?
Mutation in the Xist RNA molecule
What is a hypothetical interaction between epigenetics and environment.
Teratogen, which is not a mutagen but causes a brith defects. Hypotehsized that teratogens cause possible changes in epigenetics that mess up development. Diet is also considered an effect on aging health that could function like this.
Define epigenetics
Changes in gene expression that occur without changes in DNA sequence, how we can use the same genome and get so many different cells!
What are some characteristics of epigenetics?
1. stable, non-transient changes in expression
2. Can result in activation or repression of genes
3. Transmitted across generations (cellular and sometimes inherited)
What are the mechanisms of epigenetics (2)
1. DNA packaging-bulk activation/inact.
2. X chromosome inactivation
How does DNA packaging work?
methylation of DNA causes tighter packing (DNA off). Also histone modification via acetylation (turns DNA on) can help loosen the DNA from packaging
What is the histone code hypothesis?
the postr-translational modifications of histones, alone or in combo, function to specific and distinct DNA-templated programs
Where does the methylation of DNA occur on the code?
CpG primarily, which inhibits transcription. Some methylation patterns are gender specific (imprinting), must be faithfully copied each time DNA is replicated
How does X chromosome inactvation work?
Each X chromsome starts (in women) transcribing Xist RNA, which is going to coat the outer surface of that chromosome. The RNA coating will pack the chromosome very tightly. Th first one to oat the chromosme entirely, will be the chromosome that is inacti
How is skewed X inactivation determined?
Mutation in the Xist RNA molecule
What is a hypothetical interaction between epigenetics and environment.
Teratogen, which is not a mutagen but causes a brith defects. Hypotehsized that teratogens cause possible changes in epigenetics that mess up development. Diet is also considered an effect on aging health that could function like this.