Biology 1202B Lecture Notes - Lecture 15: Dosage Compensation, Methyltransferase, Demethylase
10 Mar 2016
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Document Summary
What is the effect of various mutations on the production of lac. An epigenetic trait is a stably heritable phenotype resulting from changes in a chromosome without alterations in the dna sequence changes take place as a result of extracellular signals constantly being rewritten by environment (cid:1) Alter the level of chromatin compaction: euchromatin (active) available for transcription heterochromatin (silent) heavily bound (not transciable, chromatin remodeling : changing of chromatin between euchromatin and heterochromatin. Means of differential gene expression between cell types. Histone modifications and dna methylation determine form of dna. Histones are modified by methylation, acetylation, phosphorylation, and other modifications. Combinations of specific histone modifications define the function of local regions of chromatin. Histones have a positive charge (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) Weakens dna histone binding reduces chromatin compaction. Hp1 is the key protein in forming mammalian heterochromatin. Binding helps other hp1 proteins to bind. Propagates heterochromatin formation (cid:1) (cid:1) (cid:1) (cid:1)
