Molecular Genetic Lecture PDF

Molecular Genetic to understand species biology Copyright © 2020, W.H. Freeman and Company  Outline Be able to describe molecular techniques that are used to cut and visualize DNA molecules. Be able to explain how DNA fragments can be copied...

Molecular Genetic to understand species biology Copyright © 2020, W.H. Freeman and Company  Outline Be able to describe molecular techniques that are used to cut and visualize DNA molecules. Be able to explain how DNA fragments can be copied with PCR. Be able to describe how the base sequence of a DNA fragment is determined. Be able to describe molecular techniques that are used for analyzing gene function, including targeted mutagenesis, Describe how techniques of molecular genetics have been used for practical applications.  19.2 Molecular Techniques Are Used to Cut and Visualize DNA Sequences A. Recombinant DNA Technology 1. Restriction Enzymes 2. Engineered Nucleases 3. GENOMELoading… EDITING WITH CRISPR-Cas B. 19.2.5 Separating and Viewing DNA Fragments C. 19.2.6 Locating DNA Fragments with Probes A. Recombinant DNA Technology : is a set of molecular techniques for locating, isolating, altering, and studying DNA segments. The term recombinant is used because frequently, the goal is to combine DNA from two distinct sources. Genes from two different bacteria might be joined, for example, or a human gene might be inserted into a viral chromosome. Commonly called genetic engineering 1. Restriction Enzymes 2. Engineered Nucleases 3. GENOME EDITING WITH CRISPR-Cas Restriction enzymes are produced naturally by bacteria and are used in defense against viruses. A bacterium protects its own DNA from a restriction enzyme by modifying the recognition sequence, usually by adding methyl groups to its DNA. More than 800 different restriction enzymes that recognize and cut DNA at more than 100 different sequences have been isolated from bacteria.  Most recognition sequences are palindromic— sequences that read the same (5 to 3 ) on the two complementary DNA strands. Loading… Restriction enzymes make double-stranded cuts in DNA, producing cohesive (sticky) ends.  Or sticky ends TABLE 19.1 Characteristics of some common type II restriction enzymes used in recombinant DNA technology  1. Restriction Enzymes 2. Engineered Nucleases 3. GENOME EDITING WITH CRISPR-Cas limitation of restriction enzymes is that because their recognition sequences are short — typically 4–8 bp in length — they occur at random many times within a genome. There are over 47,000 BamHI restriction sites in the human genome. it is impossible to precisely cut genomic DNA at a single location with restriction enzymes. To overcome this problem of numerous cuts