Human genome and disease - 24 Flashcards
What are mutations
Permanent changes to DNA sequences. Can be acquired or inherited
When are and aren’t mutations inherited
Mutations are inherited through generations when they occur in germline cells (sex cells) They are not inherited when acquired in Somatic cells (When DNA gets damaged or copied incorrectly.
Why are mutations important
They are the driving force of evolution
What 3 basic types of mutations are there
Harmful (deleterious), beneficial and no effect. (Most no effect)
What can affect mutations effects
Environmental effects (diet and exposure to toxins) Genetic background - Other genes
Why do we talk about alleles rather than genes
Mutations to a single gene can have different effects
What 2 classifications do we use
Dominant vs recessive
Loss of function vs gain of function
Why can we have dominant and recessive alleles
We are diploid (2 copies of each gene from maternal and paternal ) This means we can be heterozygous or homozygous
Why do some mutations have phenotypes
It affects the function of a gene
Describe loss of function mutations
When a mutation breaks a gene. (Stops it from functioning normally)
Are loss of function mutations often recessive or dominant. Why?
Often recessive - If there is a normal copy of the gene it can replace the loss of function
Describe gain of function mutations
Mutations that causes a gene to work too well or do something unexpected.
Are gain of function mutations often recessive or dominant. Why?
Often dominant - Over expression cannot be replaced by normal copy
How can we figure out if an allele is dominant or recessive
Examining the inheritance pattern of an allele
What are monogenic diseases
Caused by variation in a single gene
