440 likes | 576 Views
Comparative Epigenomics 1/2 Ga ë l YVERT Ecole Normale Sup é rieure de Lyon CNRS France. Sketch. Introduction Single-Nucleosome Epi-Polymorphisms in Yeast Genetic basis of SNEPs. Chromatin Epigenomics. Chromatin Epigenetics. Heritability of genotypes changing chromatin topology/dynamics
E N D
Comparative Epigenomics1/2Gaël YVERTEcole Normale Supérieure de LyonCNRSFrance
Sketch • Introduction • Single-Nucleosome Epi-Polymorphisms in Yeast • Genetic basis of SNEPs
Chromatin Epigenetics • Heritability of genotypes changing chromatin topology/dynamics • Imprinting • Transgenerational Epigenetic Inheritance • Somatic Epigenetics
in trans: Rett syndrome HDAC MeCP2 Histone Acetylation and Transcription Me Me Me Me Me Genotypes affecting chromatin states in cis: Fragile-X mutation CGG CGG CGG CGG CGG CGG FMR1 gene 200 Me Me Me Me Me Me Me Me
Prader-Willi Syndrome Angelman Syndrome Imprinting 15q11-q13 locus: ZNF127 NDN IC SNRPN UBE3A GABR genes + + + + + + + +/- + + + Paternal: Expression - - - - - - - + + + + Maternal:
Mothers on Diet with Methyl Precursors Methylation Waterland & Jirtle MolCellBiol 2003 Transgenerational Epigenetic Inheritance IAP retro-transposon ectopic transcription Avy allele Me Me Me Agouti gene
Re-visiting J-B Lamarck? 1744-1829 ‘an adaptive force’ Practise -> Adaptation -> Transmission of adaptive trait to offspring Environment -> Physiological Change -> Transmission to offspring Diet -> Epigenetic Change -> Heritable Epigenetics
Somatic Epigenetics Mikkelsen et al. Nature 2008
Chromatin Epigenetics • Heritability of genotypes changing chromatin topology/dynamics • Imprinting • Transgenerational Epigenetic Inheritance • Somatic Epigenetics
Sketch • Introduction • Single-Nucleosome Epi-Polymorphisms in Yeast • Genetic basis of SNEPs
C G What makes the difference ?
Epigenomic Profiling MNase genome tiling array All Nucleosomes
ChIP genome tiling array Marked Nucleosomes Epigenomic Profiling MNase genome tiling array All Nucleosomes
Comparison of 2 S. cerevisiae strains BY ~ S288c: laboratory, rotten fig (sequenced & assembled) - mapping: 3 replicates - H3K14ac: 6 replicates RM: haploid from vinyard isolate (sequenced & assembled) - mapping: 3 replicates - H3K14ac: 6 replicates Transcriptome already compared in standardized lab environment Analysis: NucleoMiner
Hidden Markov Model Science 2005
Hidden Markov Model Science 2005
Hidden Markov Model Science 2005
Genome alignments Map probes (single, perfect match) on each genome Use maximum probes on each genome Fit HMM parameters for each strain
Nucleosome Positioning HMM as in Yuan et al. Science 2005 Lee et al. Nature Genetics 2007
Nucleosome Positioning HMM as in Yuan et al. Science 2005 Lee et al. Nature Genetics 2007
RM BY Positioning is conserved
Screen for Single Nucleosome Epi-Polymorphisms (SNEP) ANOVA model: yijkl = u + Si + Ej + Pk + SxEij + eijkl Si = {BY, RM} Ej = {nuc, H3K14ac} Probe k
5,442 SNEP found at FDR=0.0001 Screening for SNEP 58,694 nucleosomes interrogated
Isolated or clustered? 55% are ‘isolated’
BYac SNEP hit regulatory elements evol conservation
2008 147 nucleosomes remodeled: 1.7 fold enrichment of SNEP (P = 0.01)
C C T T What in the diploid hybrid? ?
C T Allele-Specificity C MNase Seq C C ChIP T 12 Million Solexa Reads Test Allele-Specificity for 2,327 SNEPs 128 Allele-Specific SNEPs (108 far from Ty, rDNA or Telomere)
Allele-Specificity Poor correlation with parental difference
Maud de Dieuleveult X. Gidrol, CEA Evry L. Steinmetz, EMBL ProfilExpert, Lyon Lyon Grants: ATIP (CNRS), ANR Acknowledgments Jean-Baptiste Veyrieras M. Nagarajan Helene Bottin Anne-Laure Abraham