Lecture 8 Flashcards
What are chromosomes?
Matched pairs (one from mother, one from father).
How many copies of each gene does a cell contain?
2
What is an allele?
Matching copies of a gene-not necessarily identical! Leads to increased variability.
What is wildtype?
The most common (normal) phenotype or genotype. Used as a control in a lab-anything that differs is a mutant.
What is phenotype?
The appearance of an organism that results from the interaction of genes with one another and the environment
What is genotype?
The full set of genes that a given organism possesses
What is a mutation?
Any alteration of an allele that yields a different version of that allele
What is the dominant allele?
The one that is routinely expressed (Huntingtons Disease)
What is the recessive allele?
The one that is routinely unexpressed (Tay-Sach’s disease)
What is huntington’s disease?
Hereditary disease (progressive neurodegenerative disorder) characterized by chorea (ceaseless, involuntary jerky movements) and progressive dementia, ending in death. Symptoms typically start around 35+ years.
Why does Huntington’s happen?
Defect in Huntingtin gene, resulting in increased number of CAG repeats on chromosome 4. Results in brain death in the Basal Ganglia and cortex.
What is CRISPR?
“Clustered regulalry interspaced short palindromic repeats,” form of acquired immunity. Uses CAS9 to snip DNA.
What can CRISPR do?
Creates “knockout animals”- selective removal of a given gene.
Also potentially a cure for genetic disorders.
What are some issues with CRISPR?
It’s not actually as specific as we’d like, could lead to eugenics.
What are eugenics?
Science of improving the human population by controlled breeding to increase the occurrence of desirable heritable characteristics.
What is brain derived neurotrophic factor?
A protein that is important for the health of neurons-neurotrophic factors are responsible for the growth, survival, and maintenance of neurons. Shows that the wild type can still have mutations.
What are the different versions of the BDNF allele?
Val Allele-most common
Met Allele- Produces a slightly less effective form of BDNF protein- approximately 1/3 of people inherit a copy of the met allele.
What does the met allele affect?
Episodic memory
What are epigenetics?
Examines the differences in gene expression related to environment and experience-do not alter a gene, but rather allow or prevent expression.
What are some ways of altering genome expression?
1) Histone 2) DNA 3) mRNA
What is histone modification?
When a methyl group blocks the histone from opening to prevent transcription
What is DNA modification?
Methyl group binds to CG base pairs to block transcriptions
What is mRNA modification?
ncRNA binds to mRNA to block translation
In what types of people is methylation higher?
People who have committed suicide (higher in the hippocampus)
What happens with methylation in children who have experienced abuse?
Methylation happens on the glucocorticoid receptor-results in stress, PTSD, affects development, metabolism, immune response, depression.
What is genetic engineering?
The removal, addition, or modification of genes.
What are the transgenic techniques?
Transgenic animals-addition of gene
Knockout animals-removal of gene
