Cellular differentiation associated with tissue growth and development
Controlled by gene expression
Cytosine nucleotides in DNA can be methylated and this alters gene expression
Epigenetic changes can lead to differences between identical siblings and clones
Epigenetic changes may cause human diseases
Epigenetic modifications in genes that control cell division
Can lead to cancer
Cell differentiation or specialization is
Epigenetic factors
DNA methylation
Histone modification
Chromatin remodeling
Non-coding RNA
Environmental factors
Effect of DNA methylation on gene expression
1. DNA methylation is an epigenetic mechanism that occurs by the addition of a methyl (CH3) group to the cytosine nucleotide in DNA, thereby often modifying the function of the genes by affecting transcription and translation
2. Methyl groups can bind to positively charged histones to weaken the bonds between DNA and histones to remodel the chromosome structure (DNA damage)
If DNA bases or histones are overmethylated, the DNA coils thus unable to unwind and separate for transcription or gene expression
Reducing methylation of the bases or histones allows the DNA to unwind and separate for transcription or normal gene expression
