PSYC20006 Lecture Notes - Lecture 14: Dopamine Receptor D2, Nicotine, Methyl Group
10 May 2018
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Lecture 14
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- Fragile X syndrome: constriction of variant of X chromosome, 1 in 4000 males, 1 in
8000 females, cognitive difficulties, low IQs average of 40
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- FMR1 gene: important role in different parts of body, in brain → synaptic plasticity
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- Ahead of every gene (5’ untranslated) where chemicals binds to start transcription →
turning code into actual protein
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- Typically 10-40 repeats [maybe 20]; in fragile X syndrome → 200-1000 repeats of the
base sequence
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find more resources at oneclass.com
find more resources at oneclass.com
- Triggers methylation: methyl group binds to DNA in CCG repeat, also binds in
promoter region → silences gene, can’t produce gene product [protein isn’t available
when process of synaptic plasticity is taking place → severely impairs learning]
- Fragile X syndrome: monogenic disorder, can trace back to a difference of a single
gene
- Schizophrenia and autism have high heritability, in most populations 80%
- Major depression and anxiety: 40% in most populations
- No gene for schizophrenia or autism or major depression, bipolar disorder → are all
complex polygenic diseases
- Megastudies and metastudies: Combining many studies together to get statistical
power needed to detect small effects from many different genes, scaling up
- Endophenotypes: drilling down, change focus from disorder itself to something
associated with the disorder which is much easier to measure, much more reliable,
and much more likely to be in direct connection with genetic mechanism
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- Manhattan plots, show position on chromosome, vertical axis - significance
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find more resources at oneclass.com
find more resources at oneclass.com
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- Region on chromosome 10: robust association around gene ANK3 that encodes
protein Ankyrin G
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- Region on chromosome 12: gene CACNA1C → encodes alpha 1 subunit [component
of voltage-dependent calcium channel which moderates flow of calcium ions into cell
when depolarised (neuron fires)]
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Fragile x syndrome: constriction of variant of x chromosome, 1 in 4000 males, 1 in. 8000 females, cognitive difficulties, low iqs average of 40. Fmr1 gene: important role in different parts of body, in brain synaptic plasticity. Ahead of every gene (5" untranslated) where chemicals binds to start transcription turning code into actual protein. Typically 10-40 repeats [maybe 20]; in fragile x syndrome 200-1000 repeats of the base sequence. Triggers methylation: methyl group binds to dna in ccg repeat, also binds in promoter region silences gene, can"t produce gene product [protein isn"t available when process of synaptic plasticity is taking place severely impairs learning] Fragile x syndrome: monogenic disorder, can trace back to a difference of a single gene. Schizophrenia and autism have high heritability, in most populations 80% Major depression and anxiety: 40% in most populations. No gene for schizophrenia or autism or major depression, bipolar disorder are all complex polygenic diseases.
