BIOL 3450 Lecture 14: 11 February - Chapter 8 – Genes, Genomics, and Chromosomes
Document Summary
Packaging of dna into chromatin (nucleosomes: histones help package dna into chromatin, are able to neutralize phosphate backbone (neg) enables close compaction of. Dna makes more transcriptionally accessible: transcription units are unbound from heterochromatin, heterochromatin has tightly bound dna, condensed chromatin is less accessible to dna modifying enzymes, dnaase sensitivity assay. If gene is in decondensed form, dnaase creates nicks and allows dna to be cut up. Increasing amount of dna leads to different outcomes of nicking. Classification of human genome: <2% encodes protein. Of genome consists of repetitive dna: mobile dna elements (46%, tandemly repeated genes (0. 3%) rrna, 5s rrna, trna, and histones, unclassified spacer dna (~15 to 20%) Alu: depend on presence of line, reverse transcriptase, mobile elements promote evolution of new genes via exon shuffling, leads to genes with new combinations of exons. 3 functional elements required for chromosome maintenance in yeast: plasmid if plasmid contains leu + ars can replicate.
