Epigenetic Inheritance. Heritable modifications to gene expression that don’t involve changes to DNA sequence. DNA methylation: C’s of CpG doublets Changes in chromatin structure: - Covalent modifications of histones: Acetylation or Methylation of Lysines
Heritable modifications to gene expression that don’t involve changes to DNA sequence
C’s of CpG doublets
- Covalent modifications of histones:
Acetylation or Methylation of Lysines
- Changes in levels of chromatin compaction
Alters ability of TFs to:
Bind to DNA
2 Sex chromosomes (X & Y)
Dosage Compensation: Female & male cells must express X-linked genes at same levels.
At random, Xist gene from one X is transcribed at higher levels & Xist RNA coats X chromosome in cis.
highly condensed chromatin
Females, heterozygous for alleles of an X-linked coat color gene
Expression of alleles of some autosomal genes (rare) is determined by which parent they’re inherited from.
Prader-Willi Syndrome (PWS)
PWS gene is methylated during oogenesis
PWS gene is not methylated during spermatogenesis
Txn of genes is regulated by binding of TFs to enhancers/silencers.
Chromatin structure can modulate ability of activators to bind to DNA &/or activate txn.