* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Document
Nucleic acid analogue wikipedia , lookup
Gene desert wikipedia , lookup
Transcriptional regulation wikipedia , lookup
Gene expression wikipedia , lookup
Gene regulatory network wikipedia , lookup
Gene expression profiling wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Genome evolution wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Molecular cloning wikipedia , lookup
Genomic library wikipedia , lookup
Genetic engineering wikipedia , lookup
Molecular ecology wikipedia , lookup
Endogenous retrovirus wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Non-coding DNA wikipedia , lookup
Point mutation wikipedia , lookup
Community fingerprinting wikipedia , lookup
LECTURE CONNECTIONS 19 | Molecular Genetic Analysis and Biotechnology © 2009 W. H. Freeman and Company 19.3 Molecular Techniques Can Be Used to Find Genes of Interest - Shotgun cloning: one first clones a large number of DNA fragments, knowing that one or more contains the DNA of interest. - Gene library: a collection of clones containing all the DNA fragments from one source Creating a genomic DNA library - cDNA library: consisting only of those DNA sequences that are transcribed into mRNA Creating a cDNA library Advantages: fragments from actively transcribed genes; and introns do not interrupt the cloned sequence. Disadvantages: contain only sequences that are presence in mature mRNA; and sequences expressed in the tissue from which RNA was isolated. Gene Libraries • Screening DNA libraries • Plating clones of the library • Probing plated colonies or plaques In Situ Hybridization • DNA probes used to determine the chromosomal location and to visualize a gene while it is in a cell. • A labeled probe is applied to the slide. • FISH (fluorescence in situ hybridization) is used to identify the chromosomal location of human genes. • Determine the tissue distribution of specific mRNA molecules. A) Deletion on one copy of chromosome 7 in humans. B) Presence of mRNA from the tailless gene in Drosophila. • Positional Cloning • Isolating genes on the basis of their position on a genetic map. • In Silico Gene Discovery: high-speed computerized DNA data mining. • Application: isolating the gene for cystic fibrosis by positional cloning. DNA Fingerprinting (DNA Profiling) • DNA fingerprinting: the use of DNA sequences to identify individual persons. • Microsatellites: variable number of copies of repeat sequences possessed by many organisms, which can be amplified by PCR. • Application: identifying people who died in the collapse of the World Trade Center; identifying criminals; paternity tests; identify specific strains of pathogenic bacteria; etc. 19.5 Molecular Techniques Are Increasingly Used to Analyze Gene Function • Forward genetics: – Begins with a phenotype to a gene that encodes the phenotype • Reverse genetics: – Begins with a gene of unknown function, first inducing mutations and then checking the effect of the mutation on the phenotype 19.5 Molecular Techniques Are Increasingly Used to Analyze Gene Function • Site-directed mutagenesis • Reverse genetics: creating mutation in particular DNA sequences, and then studying the effects of these mutation on the organisms. • Transgenic animals: animals that have been permanently altered by the addition of a DNA sequence to their genome. 19.5 Molecular Techniques Are Increasingly Used to Analyze Gene Function • Knock out mice: a normal gene of the mouse has been fully disabled. • Knock in mice: a mouse carries an inserted DNA sequence at specific locations. 19.5 Molecular Techniques Are Increasingly Used to Analyze Gene Function • Silencing genes with RNAi • Using RNAi for the treatment of human disease: lowering ApoB with RNAi • Model Genetic Organism • The mouse, Mus musculus Concept Check 1 A geneticist is interested in the immune function of mice, and induces random mutations in a number of genes in mice and then determines which of the resulting mutant mice have impaired immune function. This is an example of ________. a. b. c. d. forward genetics reverse genetics both forward and reverse genetics neither forward nor reverse genetics 19.6 Biotechnology Harnesses the Power of Molecular Genetics • Pharmaceuticals • Human insulin • Specialized bacteria • Agricultural products • Oligo nucleotide drugs • Genetic testing • Gene therapy • Direct transfer of genes into humans to treat disease