Mito Genetics and Forensic DNA Analysis Flashcards
What are mito diseases associated with? What do they include?
Ox/phos mutations; neuropathies, encephalophaties, myopathies
Is the mito self-sufficient? What does it rely on? What can mito defects be attributed to? What type of inheritance is seen with mito DNA?
No; nuclear genes; autosomal or X-linked mutations, or mutations in mito DNA; matrilineal DNA (most mito transmitted in egg cytoplasm)
What is homoplasmy? Heteroplasmy? What do both mean for children in cases of eg disease?
Population of mito all having same genetic composition within a cell; two or more different pops of mito in a cell; homoplasmy means that children will inherit whatever the mother has for mito DNA, whereas heteroplasmy could result in higher freqs of mutant cells or lower freqs in the children
For a cell to express dysfunction, what is a threshold? How can the disease manifest in individuals?
Mutant mito must be about 85%; large number of dysfunctional mito throughout body or within target organ/tissue
What mechanisms can help explain why mito disorders are progressive with late onset? Would these mutations acquired occur in the progeny?
Replicative segregation (as cells divide, relative proportions of mutant mito might change over time) and acquired mutation (new event followed by mutation proliferating in the population); no, because they occur in somatic cells
Is distribution of mito to daughter cells precise in somatic cell division?
NOOOO
What is MERRF? What type of disorder is it?
Myoclonic epilepsy with ragged red fiber disease; mitochondrial disorder
What is diagnosis of a mito disorder complicated by? What can mito disorders possibly explain?
Heteroplasmy and variable expression, maternal inheritance, progressive nature of the disease; unexplained neuro defects
In general, what can be said about having more mutant mito?
Disease tends to be more severe
What is forensic DNA analysis?
Use DNA tech to obtain in on genetic identity of individual and how to relates to criminal, medical, or scientific investigation
What is used in forensics DNA-wise? What regions of the DNA need to be examined?
mito and nuclear DNA; regions with highest degrees of polymorphism, like the hypervariable minisatellite regions used with DNA fingerprinting
What are some problems with DNA/forensic analysis? What needs to be analyzed? What should you take into consideration?
Poor sample collection, mislabeling, poorly prepared sample, degradation (heat and liquids), and contamination; Look at polymorphisms with enough variability; allele frequencies vary b/w pops and among racial and ethnic groups
What can mito DNA analysis help elucidate? Why can it be better than nuclear DNA sometimes? Why might it not be as good?
Link individuals by comparing maternal mito lineages; siblings carry the same mito DNA and the mito DNA is less prone to degradation (multiple copies in every cell); however, you cannot SPECIFICALLY ID AN INDIVIDUAL!!!!
What can nuclear DNA be used for that mito DNA cannot be? When would this be useful (4)?
For ID of an individual; military, mass disaster, criminal cases, medical cases
Can you identify identical twins based solely on alleles? What could distinguish them?
No; could use fingerprints (phenotypic), hair, blood (drugs, metabolites), and footprints (size of feet)
