1. Non-Coding Areas & Mutations Within the human genome the majority of the DNA (~75%) is made up of sequences not involved in coding for proteins, RNA, or regulatory sequences. In other words it is what geneticist used to call "junk DNA". – exon regions - 1.5% much exists as multi-gene families –a & b hemoglobin exist in the same gene – also contains pseudogenes - genes that resemble the active transcript but do not code for a functional protein Ribosomal RNA will have hundreds of gene copies in the same gene transcript – regulatory regions - 24%

2. unique non-coding - 15% repetitive DNA not related to transposable elements -15% – contains mini-duplicated regions (GTTAC) that span 100s to 1000s of nucleotides – includes regions of high density including telomeric and centromeric regions formerly called satellite DNA repetitive DNA including transposable elements - 44% – known as "wandering elements" – transposons - move by a copy &paste mechanism always leaving behind a copy – retrotransposons - make an RNA transcript 1st- may be left-over from retroviruses – reason for the expanding genome of most Eukaryotes – within the transposable elements is found Alu which makes up 10% of genome. Alu repeats code for RNA of unknown function

3. Mutations leading to genomic evolution Duplications and the subsequent mutations that follow mutations are responsible for much of the diversity in organisms (ex:globin superfamily). Mutations that infer advantage to a species don't always improve the function of the protein product but may completely change the function (ex: lysozyme and a -lactalbumin). Such changes are used to traces the evolution of species through the evolutionary tree.

4. Duplications & Deletions – polyploidy - complete set of chromosomes is added to the genome (3n, 4n,...) common in plants (sweet corn) caused by non-disjunction – unequal crossing over creates a duplication in one chromosome and a deletion in the other common in areas of repeats exon-shuffling (swapping of like exon regions making new combinations of genes) – slippage shifting of the reading frame during DNA replication – Transposable elements may lead be the most important agent of change in genomic evolution the majority of the genome consists of them depending where the land and what is contained in them the effect may be different