BIOL321 Lecture Notes - Lecture 7: Chromosome, Genetic Variability, Pyrimidine
29 Apr 2016
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Document Summary
The source of variation is mutation, therefore variation requires genetic accidents . Transcription is the act of copying dna into rna, while translation is turning rna into protein. Often the 3rd position sequence in the codon is redundant so it can be mutated without any effects. Most dna doesn"t code for amino acids, the exon is expressed while the intron is interspersed. A mutation that is purine to purine or pyrimidine to pyrimidine is called a transition. A mutation that is purine to pyrimidine or vice versa is called a transversion. Mutation that still produces the same codon is called a synonymous (silent) mutation. Non-synonymous mutations are : missense - which produces a different amino acid, nonsense - which doesn"t produce an amino acid (stop) Indels make frameshifts, which can be a lot more disastrous. Dna slippage happens in places with a lot of repeated characters, and can cause additions or deletions in the dna.
