o) powerpoint enhancer evolution across 20 mammalian species
TRANSCRIPT
Regulatory difference vs. phenotypic difference
Enhancers & promoters
Enhancers: regulate transcription
Promoters: regulate binding of RNA polymerase
Enhancers & Promoters Where are they located?
Conserved or Recently evolved?
Do they differ between species?
http://meatex.co.uk/product/pig-liver/http://hubpages.com/hub/How-To-Understand-Your-
Blood-Tests-Biochemistry
http://www.askjpc.org/wsco/wsc_showconference.php?id=520
Histones & Lysine H3K27ac
H3K4me3
Enhancers identified by H3K27ac
Promoters identified by H3K27ac & H3K4me3
http://www.rndsystems.com/product_detail_objectname_exactachip.aspx
Enhancers bound to H3K27ac are located away from the start codon region & are more apt to evolve while promoters bound to H3K27ac & H3K4me3 are located near the start codon region.
Mapped active promoter & enhancer elements
Adult Somatic tissue
20 species of mammals
Met Criteria
I. Capture large fraction of mammalian phylogenetic tree
II. Profile major placental orders
III.Extend understanding of regulatory evolution of mammals w/ highly divergent phenotypes
Biological replicates ≥ 2
Exceptions: Sei Whale & Dolphin
Histone rich markers w/ biologically reproducible peaks
H3K27ac
H3K4me3
Chromatin immunoprecipitation
Verify if protein is localized to specific DNA sequence
ChIP-seq
Method to analyze protein interactions w/ DNA
Gel electrophoresis &
nanodrop spectrophotometer
Illumina genome analyzerhttp://www.bio.brandeis.edu/haberlab/jehsite/chIP.html
The majority of enhancers are not conserved Exception: regions coding for primary liver functions
Exaptation from Ancestral DNA sequence
http://www.telegraph.co.uk/news/uknews/crime/6781990/Bat-preservation-area-being-used-to-rob-people.html & http://www.lasgralariasfoundation.org/RLGvarious/slides/saturnid%20moth%202.html
https://www.flickr.com/photos/mikewiz/11809326866/in/photostream/
Exaptation vs. Adaptation
o Natural selection for current fxn.
o A feature that was notproduced by natural selection for current use
Promoter regions, located near TSS, are highly conserved compared to enhancer regions, located away from TSS, which evolve relatively quickly except for enhancers that regulate transcription of primary liver function.
Enhancers w/ H3K27ac location
Promoters w/ H3K27ac & H3K4me3 location
Enhancers evolve quickly through exaptation
Areas of highly conserved Enhancers
Primary liver functions
Areas of highly conserved Promoters
“Housekeeping” functions
From this knowledge researchers may further progress in the analysis of regulatory evolution & its effects