1. The Central Dogma The Central Dogma traces the flow of genetic information DNA Replication, Transcription, and Translation take place in human cells as part of their normal lifecycle Some viruses make use of RNA replication to reproduce Retroviruses, such as HIV, engage in reverse transcription, which is the process of inserting RNA into DNA Source: http://cats.med.uvm.edu/cats_teachingmod/microbiology/courses/genomics/images_new/1_centraldogma_wisc_13.jpg

2. The genetic code shows how a nucleotide sequence is interpreted to produce proteins by defining the mapping of codons (a set of 3 nucleotides) to amino acids Each codon corresponds to exactly one amino acid –There are only 20 amino acids, but 64 (4 3 ) possible codons –Each amino acid may be mapped to multiple codons I.e.Leucine, Proline, and Arginine have 4 corresponding codons Specific codons indicate the start and stop sites for genes Source: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/code.gif The Genetic Code

3. Variations in the Genetic Code There are many variations to the genetic code Below is the standard genetic code, and to the right of it is the genetic code for invertebrate mitochondrial DNA, with variations highlighted by red boxes. Stars indicate termination sites, and lowercase i’s indicate start sites These variations can be used in taxonomic classifications, as similar genetic codes indicate similar ancestry The Standard Genetic CodeThe Invertebrate Mitochondrial Code Source: http://www.ncbi.nlm.nih.gov/Taxonomy/Utils/wprintgc.cgi