BIO 181R notes H and G,Mol_ Bio_ and Medicine

BIO 181R notes H and G,Mol_ Bio_ and Medicine -...

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Introduction to Human Genetics Humans and Genetics Principles of Mendelian Genetics apply equally well to humans as any other organism. Basic Goals 1. For any human phenotype, what is the underlying genotype? 2. Can the gene or genes responsible for a phenotype be isolated, characterized, and expressed? 3. From the DNA sequence(s) of the human gene(s) causing a phenotype, does the knowledge of the resulting protein product lead to medical diagnosis or even disease prevention or cure Challenges of Human Genetics 1. Only approximately 1500 human genes have known phenotypes 2. Most major medical problems such as diabetes, heart disease, obesity, mental illness and cancer are complex, with both genetic contributions from many different genes, and environmental contributions 3. How can genetic analysis be used for routine medical care in ethical and economical ways? Human Chromosomes 46 chromosomes: 22 pairs of autosomes and 2 sex chromosomes Sex chromosomes may be similar (XX)-in females, or different (XY)-in males Genes that determine male characteristics are on the Y-chromosome Human Genome Project Milestones New era in human health sciences based on genomics has begun, with profound implications on how medicine will be practiced in 21st century "Draft" sequences of complete human genome reported in February 2001 by Human Genome Project (Nature article) and Celera Genomics (Science Article) "Near complete" sequence of human genome reported in October 2004 by International Human Genome Sequencing Consortium. Genome Project Status in 2006: 1. 2.85 billion bp interrupted by only 341 gaps 2. 99% of the euchromatic genome completed to accuracy of ca. 1 error in 100,000 bp
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3. Average contiguous segments is 38 million base pairs 4. Heterochromatic regions with repetitive DNA, especially centromeres, not yet determined Completed Human Chrosomes by Year : 1999: Chromosome 22 2000: Chromosome 21 2001: Chromosome 20 2003: Chromosomes 14, Y, 7, 6 2004: Chromosomes 19,10, 9, 5, 16, 13, 18 2005: Chromosomes X, 2, 4 2006: Chromosomes 8, 15, 12, 11, 17, 3, 1 Nature Web Focus The Human Genome - Nature Publishing Group maintains a web site that links to scientific articles reporting the finished genome sequence for each human chromosome. Future of Human DNA Sequencing NIH funding projects aimed at the $1000 human genome X-Prize competition announced. $10M award for first group to sequence 100 human genomes in 10 days Knowing your genome will one day be as commonplace as knowing your height, weight and blood type, and might influence your ability to get medical insurance Human Genome Features 3.08 billion base pairs of DNA in the haploid genome 20,000-25,000 genes, but more than 100,000 proteins due to alternative splicing The average gene size is 3000 bp. The largest known human gene is dystrophin, 2.4 million bp Coding regions make up only about 2% of the genome
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BIO 181R notes H and G,Mol_ Bio_ and Medicine -...

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