organization of the human genome genome structure nuclear vs. mitochondrial genomes gene families...
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Organization of the human genome
• Genome structure
• Nuclear vs. mitochondrial genomes
• Gene families
• Transposable elements
• Other repeated sequences
Organization of the human genome
• Mitochondrial genome–Small (16.5 kb) circular DNA–rRNA, tRNA and protein encoding genes (37)–1 gene/0.45 kb–Very few repeats–No introns–93% coding–No recombination–Maternal inheritance
Organization of the human genome
Limited autonomy of mt genomesmt encoded nuclear
NADH dehydrog 7 subunits >41 subunitsSuccinate CoQ red 0 subunits 4 subunitsCytochrome b-c1 comp 1 subunit 10 subunitsCytochrome C oxidase 3 subunits 10 subunitsATP synthase complex 2 subunits 14 subunitstRNA components 22 tRNAs nonerRNA components 2 components noneRibosomal proteins none ~80 Other mt proteins none mtDNA pol, RNA pol
etc.
Organization of the human genome
• Nuclear genome– 3300 Mb– 23 (XX) or 24 (XY) linear chromosomes– 65-80,000 genes– 1 gene/40kb– Introns– 3% coding– Repetitive DNA sequences (45%)– Recombination – Mendelian inheritance (X + auto, paternal Y)
Organization of the human genome
• Contrasting gene densities–HLA high density–Dystrophin low density
Organization of the human genome
• Gene families–Functionally similar genes are occasionally
clustered, but usually dispersed throughout the genome
Organization of the human genome
• Genes vary in size and exon content
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Organization of the human genome
• Genes within genes–Intron 26 of the NF1 gene contains three
internal genes.
Organization of the human genome
• Gene families defined by conserved amino acid motifs–DEAD box.–WD repeat families
Organization of the human genome
• Ig superfamily–Cell surface receptors–Similar domain structure
Organization of the human genome
• Clustered gene familiesGrowth hormone 5 copies (67kb)
globin 7 copies (50kb)
Hox genes (multi) 38 four clusters
Olfactory receptors 1000 in 25 large clusters
Organization of the human genome
• Interspersed gene familiesPax 9 copies
Actin >20 copies
Alu elements (repeats) 1.1 million
LINE elements (L1) 200-500,000
Organization of the human genome
• HLA heavy chain gene cluster–Gene fragments–Pseudogenes–Truncated genes
Organization of the human genome
• Processed pseudogenes–Originate by reverse transcription–TPRT
Organization of the human genome
• Chromosomal location of repeats–telomere–Centromere–LINE elements (Alu Elements)–Minisatellites
Organization of the human genome
• Formation of higher order repeat units
Organization of the human genome
• Human transposable elements
Organization of the human genome
• Transposable elements with RNA intermediates–Endogenous retroviruses–Retrotransposons–Retropseudogenes
Organization of the human genome
• Human transposable elements–Alu elements–LINE elements
Organization of the human genome
• Mobile elements and gene structure–RB1 region
• Alu• LINE• Simple sequence repeats
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