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MUTATION AND GENE EDITING - Coggle Diagram
MUTATION AND GENE EDITING
MUTATIONS
SUBSTITUTIONS
SILENT
DNA CHANGE DOES NOT ALTER THE AMINO ACID SEQUENCE
THIS IS BECAUSE THE GENETIC CODE IS DEGENERATE (MORE CODONS CODE FOR THE SAME AMINO ACID)
MISSENSE
DNA CHANGE ALTERS A SINGLE AMINO ACID
NONSENSE
DNA CHANGE CREATES A PREMATURE STOP CODON WHICH SHORTENS THE POLYPEPTIDE
INSERTIONS
THE ADDITION OF A NUCLEOTIDE IN THE DNA SEQUENCE
THIS CAUSES A FRAMESHIFT MUTATION WHICH CHANGES THE READING FRAME
A MUTATION IS A CHANGE IN THE DNA SEQUENCE THAT ENCODES FOR A TRAIT
DELETIONS
THE REMOVAL OF A NUCLEOTIDE IN THE DNA SEQUENCE
THIS ALSO CAUSES A FRAMESHIFT MUTATION WHICH CAN CAUSE THE POLYPEPTIDE TO NOT FUNCTION
A SINGLE NUCLEOTIDE POLYMORPHISM (SNP) IS A NUCLEOTIDE CHANGED IN A LARGE PROPORTION OF THE POPULATION
CAUSES OF MUTATIONS
PROOFREADING ERRORS
DNA POLYMERASE IS RESPONSIBLE FOR PROOFREADING DURING DNA REPLICATION
IF DNA POLYMERASE PROOFREADS INCORRECTLY, THIS CAN CAUSE A MUTATION (MISMATCH REPAIR)
MUTAGENS
A MUTAGEN IS AN AGENT THAT INDUCES A CHANGE TO THE DNA
FOR EXAMPLE, CHEMICAL MUTAGENS SUCH AS REACTIVE OXYGEN SPECIES
ANOTHER EXAMPLE, PHYSICAL MUTAGENS ARE RADIATION (X-RAYS)
RANDOMNESS
MUTATIONS CAN OCCUR ANYWHERE IN THE BASE SEQUENCE
THERE IS NO SET CONSEQUENCE FOR A CHANGE TO THE BASE SEQUENCE
THEY CAN BE NEUTRAL, NEGATIVE OR POSITIVE
GERM AND SOMATIC CELLS
SOMATIC MUTATIONS OCCUR IN A SINGLE BODY CELL AND CAN NOT BE INHERITED
GERMLINE MUTATIONS OCCUR IN GAMETES AND CAN BE PASSED ONTO OFFSPRING
GENETIC VARIATION
MUTATIONS ARE THE ORIGINAL SOURCE OF ALL GENETIC VARIATION
MUTATIONS ARE ESSENTIAL FOR EVOLUTION BY NATURAL SELECTION
GENE KNOCKOUT
TO DETERMINE THE FUNCTION OF GENES, THE GENE IS REPLACED WITH A NON-FUNCTIONING ONE TO DETERMINE THE EFFECT IT HAS ON A TRAIT
GENE EDITING
SICILIAN ROUGE HIGH GABA TOMATOES ARE AN EXAMPLE OF PLANT EDITING USING CRISPR-CAS9 SYSTEM
GABA IS SYNTHESIZED BY THE TOMATO AS THEY GROW, ACCUMULATING ITS CONCENTRATION OVER TIME
THE CONCENTRATION DECREASES DURING RIPENING AS GABA IS CONVERTED TO GLUTAMATE BY THE ENZYME GLUTAMATE DECARBOXYLASE
THE GENE FOR THIS ENZYME WAS EDITED SO THAT THE ENZYME IS INACTIVE AND GABA CONCENTRATIONS PERSIST UNTIL THE TOMATOES ARE EATEN
CONSERVED SEQUENCES IN GENES
FUNCTIONAL REQUIREMENTS
ANY MUTATION THAT CHANGE THE SEQUENCE ARE DELETED BY NATURAL SELECTION BECAUSE THEY PREVENT THE FUNCTION FROM BEING CARRIED OUT
SLOWER MUTATION RATES
THE CONSERVED SEQUENCE IS IN A REGION THAT EXPERIENCES A LOW MUTATION RATE