Download DNA Methylation

DNA Methylation
DNA Methylation
• DNA methylation, the addition of methyl groups to
certain bases in DNA, is associated with reduced
transcription in some species
• DNA methylation can cause long-term inactivation
of genes in cellular differentiation
• In genomic imprinting, methylation regulates
expression of either the maternal or paternal
alleles of certain genes at the start of development
What is Genomic Imprinting?
• Genomic imprinting is the epigenetic phenomenon by
which certain genes are expressed in a parent-oforigin-specific manner.
• If the allele inherited from the father is imprinted, it is
thereby silenced, and only the allele from the mother
is expressed.
• If the allele from the mother is imprinted, then only
the allele from the father is expressed.
• Forms of genomic imprinting have been demonstrated
in fungi, plants and animals.[1] Genomic imprinting is a
fairly rare phenomenon in mammals; most genes are
not imprinted.
What is EPIGENESIS (epigenetic)?
• Epigenetics is the study, in the field of
genetics, of cellular and physiological
phenotypic trait variations that are caused by
external or environmental factors that switch
genes on and off and affect how cells read
genes instead of being caused by changes in
the DNA sequence
• Two of DNA's four nucleotides, cytosine and
adenine, can be methylated. Adenine
methylation is restricted to prokaryotes
• Two of DNA's four nucleotides, cytosine and
adenine, can be methylated. Adenine
methylation is restricted to prokaryotes
• Methylation modifications that regulate gene
expression are usually heritable through
mitotic cell division; some methylation is also
heritable through the specialized meiotic cell
division that creates egg and sperm cells,
resulting in genomic imprinting
• DNA methylation also forms the basis of
chromatin structure, which enables a single
cell to grow into multiple organs or perform
multiple functions
• DNA methylation also plays a crucial role in
the development of nearly all types of
cancer.[4]