Chapter 13 Section 13.3 The Human Genome

Genomes contain all the information needed for an organism to grow and survive The Human Genome Project (HGP) An international project that was completed in 2003 Goal: to determine the sequence of the approximately three billion nucleotides that make up human DNA and to identify all the 23,299 human genes

The Human Genome Project The genetic information contained within the human genome had to be decoded in order to uncover important sequences Once decoded, found that the genome is filled with long stretches of repeated sequences that have no direct function – noncoding sequences DNA fingerprinting – long stretches of noncoding regions are unique to each individual Forensic scientists use DNA fingerprinting to identify suspects and victims in criminal cases, to determine paternity and to identify soldiers killed in war

The Human Genome Project People can be identified using the genetic information contained in blood, hair, semen, or skin to be used in a DNA fingerprint

Identifying Genes Once the genome has been sequenced, need to identify the genes and determine their functions Many functions of the genes in the human genome are still unknown In bacteria and yeast, researchers have identified ORF’s – stretches of DNA containing at least 100 codons that begin with a start codon and end with a stop codon (protein synthesis?) More complicated in higher organisms

Bioinformatics The field of study that involves creating and maintaining databases of biological information Computers in biology have become extremely important Used to analyze the genomes of humans and other organisms

DNA Microarrays Tiny microscope slides or silicon chips that are spotted with DNA fragments Large amounts of information can be stored in one small slide or chip Genetic or environmental? Figure on page 377 Can be used to identify new genes and to study changes in the expression of proteins under different growth conditions

The Genome and Genetic Disorders More than 99% of all nucleotide base sequences are exactly the same in all people Sometimes there are variations in the DNA sequence that occur when a single nucleotide in the genome is altered (single nucleotide polymorphisms- SNPs) Many SNPs have no effect on cell function but may be associated with many different types of genetic disorders

The HapMap Project Haplotypes – regions of linked variations in the human genome Figure on page 378 Once completed, the HapMap will describe what the variations are, where they occur in our DNA, and how they are distributed Will help researchers find genes that cause disease and affect an individual’s response to drugs

Pharmacogenomics The study of how genetic inheritance affects the body’s response to drugs Benefit: more accurate dosing of drugs that are safer and more specific Hope to be custom-made for individuals Based on individual’s genetic makeup Will increase safety, speed recovery, and reduce side effects

Gene Therapy A technique aimed at correcting mutated genes that cause human diseases Insert a normal gene into a chromosome to replace a dysfunctional gene Need to engineer viral vectors that are nontoxic and do not activate the immune system in order for gene therapy to be accepted by the FDA (gene therapy halted in 2003)

Genomics and Proteomics Genomics: the study of an organism’s genome Remember: when a gene is expressed, a protein is produced Proteomics: the study and cataloging of the structure and function of proteins in the human body Proteomics allows researchers to look at hundreds or thousands of proteins at the same time Proteomics is anticipated to revolutionize the development of new drugs to treat diseases – Type II diabetes, obesity, and atherosclerosis

Careers Biomedical research Forensic science Pharmaceuticals Agriculture Medicine Genetics Can you think of others?