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 - Changes in levels of chromatin compaction
Alters ability of TFs to:Bind to DNAActivate txn
Humans have 23 pairs of chromosomes2 Sex chromosomes (X & Y)22 Autosomes
Dosage Compensation: Female & male cells must express X-linked genes at same levels.
X-inactivation in female mammals
At random, Xist gene from one X is transcribed at higher levels & Xist RNA coats X chromosome in cis.
Heterochromatin:highly condensed chromatin
Parental ImprintingExpression 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
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