define polymorphism.
- this is a variation in the common DNA sequence that occurs and is sustained within a population at a frequency that is higher than that of an average mutation.- found in more than 1% of the population
what are the five types of polymorphisms?
1) SNP (single nucleotide polymorphism)2) RFLP (restriction fragment length polymorphism)3) VNTR (Variable Number Tandem Repeat)4) SSR (Simple Sequence Repeat)5) CNV’s (Copy Number Variants)
what is the difference between an SNP and a point mutation?
- SNPs occur at a higher frequency- SNPs have little to no affect on phenotype
What is a RFLP and what is the result?
(restriction fragment length polymorphism)- basically an SNP within an enzyme restriction site- results in longer fragment cut by restriction enzyme
what are microsatellites?
- another name for SSR- tandem repeated sequences 1-6 nucleotides long
what is the most useful group of polymorphic markers for gene mapping and personal identification?
- SSR aka microsatellites
what is the difference between VNTR and SSR?
- VNTR are usually longer repeated sequences (10-100bp vs 1-6bp)- minisatellite vs microsatellite
what is a CNV?
(copy number variants)- deletion or duplication of around 50kb to 12Mb
what is meant by “de novo”?
“possessed by neither parent”
how are CNVs caused?
- usually unequal crossing over during meiosis or they are inherited
what is the mutation that results in sickle cell anemia?
- GAG to GTG- Glutamic Acid to FUCKING valine- hydrophillic hemoglobin to hydrophobic hemoglobin
how many variants do RFLPs have?
2, present or absent
how many variants do SNP’s have?
4, A, T, G, C
what is the normal function of P-450?
- metabolism of xenobiotics and toxic compounds in the liver- acts as hydroxylases and methyl oxidases- primary enzyme in metabolism of drugs
why is the CYP2D6 enzyme important?
- responsible for metabolizing 20% of drugs in the liver. - gene expression that is too great results in ineffective drugs and too slow will result in toxicity.
why is the CYP2C9 enzyme important?
- metabolizes 16% of drugs- used to clear coumadin (Warfarin) which treats blood clotting in thrombophilia
why is the CYP2C19 enzyme important?
- converts clopidogrel (Plavix) into the active compound (oxo-clopidogrel).
repeat sequences account for what percent of human DNA?
50%
