0319 mitochondrial genome and mutations Flashcards
What is the definition of a genome
A genome is the entirety of an organisms hereditary information. In humans it includes the 23 pairs of chromosomes and the 1 small chromosome in mitochondrial DNA
What are the main functions of mitochondrial DNA (i.e. what information does their DNA relate to)
Mitohcondrial genes contain the instructions/information for oxidative phosphorylation, mitochondrial protein synthesis and RNAs
What are reactive oxidative species and where are they produced
ROS are chemically reactive molecules containing oxygen produced as a byproduct of oxidative phosphorylation. Most commonly they are produced by complexes 1 and 3 in the inner mitochondrial membrane
Where do most mitochondrial genes come from (maternal or paternal)? Why is this?
Most of our mitochondrial genes come from our mother. This is because there is much more mitochondria in the egg compared to the sperm (100000:100)
What causes the increase in accumulation of mitochondrial mutations (compared to mutations in the DNA)
The accumulation of mitochondrial mutations is mostly due to the absence of repair mechanisms in mtDNA
What are the 2 factors that contribute to the difference in genetic sequences of mtDNA
Random mutations and inheritence
What cells in our body are most susceptible to mitochondrial disease
Cells with the highest energy demand (and therefore the most mitochondria). E.g. the cells in the central nervous system
List one example of a mitochondrial linked disease
Lebers hereditary optic neuropathy (LHON)
Define penetrance. Give an example of a disease with a high penetrance. Give an example of one with variable
Penetrance is the probability that a given phenotype will appear given that the genotype is present. Huntingtins disease has 100% penetrance while haemochromatosis has a highly variable penetrance
Define expressivity. Give one example of a disease with a varirable expressivity
Expressivity is the variation in phenotype among individuals carrying a particular phenotype. Marfan syndrome is a disease with highly variable expressivity
What factors can distort the pedigree of an inherited disease
Expressivity and penetrance
List some factors that can influence the impact of a disease on an individual
Expressivity, penetrance, survivability, other gene interactions, environmental factors and new mutations
