3.36B: Understand How Most Genetic Mutations have No Effect on the Phenotype, Some have a Small Effect and Rarely do they have a Significant Effect

MUTATION: Rare and random change in DNA sequence coding for new alleles for gene

Diagram showing an Example of Mutation

EFFECTS OF MUTATIONS:

HARMFUL

Harmful mutations alter the base pair sequence in genetic code, coding for a different protein which may abrogate its normal function Harmful mutations may cause genetic disorders that can be passed onto generations (e.g Cystic Fibrosis) Harmful mutations may cause a drastic effect on phenotype of an individual

NEUTRAL

Neutral mutations alter the base pair sequence in genetic code, but has no effect on function of Protein Neutral mutations may not affect the chances of survival of an individual

BENEFICIAL

Beneficial mutations alter the base pair sequence in genetic code, coding for a different protein which allows organism to be better adapted to environment, thus increasing chances of survival Beneficial mutations may be passed onto generations, therefore increasing chances of survival of species Beneficial mutations may be caused by evolution as a means of Natural Selection, increasing the chances of survival of species if they are passed onto generations e.g carriers of Sickle Cell Allele are more resistant to Malaria