Personalized Med Flashcards
Describe the treartment of dx
What causes disease?
Diseases are partially the results of gene expressions and regulations
Use of Genomics
Genomics provides better understanding on the development and progression of diseases such as cancer and cardiovascular disease
Genomics also ensures patients’ safety by providing information on drug metabolism and drug-drug interaction
Goal of parmacogenomics
Our goal of pharmacogenomics is to achieve 4 “right”
Right patient
Right drug
Right time
Right dose
Describe the cells in the human body
Around 30-40 trillion cells
Over 200 different types, such as neurons, epithelial cells and red blood cells
As many as 100 billion cells die each day and replaced by new cells
How are new cells made? What is this process called?
New cells are made by cell division (one mother cell divides into two daughter cells)
Each cell division process is called a “cell cycle”
Describe interphase of the cell cycle
G1 (Gap 1): cell grows and prepares for DNA replication
S (synthesis): DNA replication
G2 (Gap 2): cell continues to grow and prepares for mitosis
M (mitosis): cell stops growth and starts division
G0 (Gap 0): cell has left the cell cycle and stopped dividing
Checkpoints: one in G1 and one in G2 and apoptosis starts if anything goes wrong
G1 checkpoint: DNA Synthesis
G2 checkpoint: preparation for mitosis
R (restriction point): cell commits to the cycle for division- IN G1
Describe mitosis
M phase
Prophase: condensation of chromatin and disappearance of nucleus
Metaphase: chromosomes align on the metaphase plate
Anaphase: chromosomes split and move to the opposite poles of the cell
Telophase & cytokinesis: spindle disappears, nucleus reforms and mother cell divides into two daughter cells
Anaphase checkpoint
When are growth factors no longer required in the cell cycle?
No more growth factors after the R point
Cell Cycle Checkpoints
How many chromosmes in the human body?
23 pairs of chromosomes in human
What is a chromosme?
Complex of a DNA molecule and proteins
DNA SHape.How many base pairs?
DNA molecule: linear double-stranded (50 – 250 million base pairs)
How many genes in a chromosme? How many base pairs?
Average chromosome: 2500 – 5000 genes within 130 million base pairs
Microband
Microband: 3 – 5 million base pairs and 60 – 120 genes
Do chromsomes all code for genes?
Only 10% of human chromosomes code for genes
Rest of human chromosomes: may play regulating roles
Cell Cycle and Growth Factors
Before R, need growth factors (cell cycle stimulated by growth factors)
Past R, growth factors are not required anymore
What stimulates cell cycle?
Cell cycle stimulated by growth factors
How is DNA compacted? What does it do?
DNA is wrapped around histones
A histone is a protein that provides structural support for a chromosome.
Describe histones
A nucleosome is a section of DNA that is wrapped around a core of proteins.
DNA is a linear molecule
DNA molecule is condensed –> Wrapped around histones –> Each one has 2, get an octomer, DNA wraps around on the surface –> H1 stabilizes nucleosomes by binding to the dyad region between the entry and exit sites of DNA. (acts as a lock in space)
Highly compacted Need to open it up to do protein synthesis –> Must be in linear form
Linker DNA describes the non-nucleosomal DNA connecting two or more nucleosomes in an array.
What is a gene?
A portion of chromosomal DNA sequence required for the production of a polypeptide (protein) or a functional RNA molecule
Size of a gene?
Size: small (1.5 kb) – large (2000 kb)
What sequences are in a gene?
Include the coding sequence and adjacent sequence required for regulation of expression (such as promoters)
What size is mature mRNA?
Mature mRNA is about 1/10 of the gene size (RNA splicing)
What is RNA splicing?
RNA splicing: precursor mRNA → mRNA
Describe the genetic code?
Four types of nucleotides in DNA: A, T, G and C
Pairs: A-T and G-C
Four types of nucleotides in mRNA: A, U, G and C
Pairs: A-U and G-C
Gene Expression
Gene expression: Gene mRNA protein
Transcription: Gene mRNA
Translation: mRNA protein
How many genes expressed in human cells?
Only ~15,000 genes expressed in a typical human cell
Expression varies from one cell to another
Eukaryotic gnese contain….
Eukaryotic genes: exons and introns
What is involved in disease?
Gene malfunction is involved in many diseases, such as TP53 in different types of cancer
Describe what are promoters?
DNA sequences that “promote” gene expression
Required for DNA transcription (i.e., mRNA synthesis)
Typically located upstream of the genes
RNA polymerase binding site
Direct the exact place to initiate DNA transcription
Determine when and how a gene is transcribed
Promoter methylation represses gene transcription
When did the human genome project start? WHo?
Initiated in 1990 and finished in 2006
Funded by the US Department of Energy and the National Institutes of Health and involved research institutes from six countries
What did the human genome discover?
Complete DNA sequence of human
Most complex and largest genome (up to now)
Nuclear DNA vs Mitochondrial DNA
Nuclear DNA genome: 22 pairs of autosomes (diploid) and 2 sex chromosomes (X and Y): ~ 3 billion base pairs
~19,000 genes
Mitochondrial DNA genome: ~ 17 thousand base pairs
38 genes
What is required to read a genome?
ENCyclopedia Of DNA Elements (ENCODE)
Annotation of functional elements encoded in human genome
What are gene switches?
Gene switches: non-gene parts of DNA contributing to human diseases such as:
Multiple sclerosis
Lupus
Rheumatoid arthritis
Crohn’s disease
Who termed the term genomics and when?
The term “genomics” was coined in 1986 by Tom Roderick (Jackson Laboratory, Maine)
What is genomics?
Genomics is an interdisciplinary study of human genome
Structure
Function
Mapping and annotation
Regulation
Evolution
Understand disease development – interaction between genome and environment
Describe the different types of genomic studiues?
What are the four essential parts of genomics?
Genetic variations
Gene expressions
Gene regulations
Gene correlations
Types of Genetic Variations
Single nucleotide polymorphisms (SNPs)
Copy number variations (CNVs)
Insertions and deletions
Large scale variations
Structural variations
Most common Genetic VAriation
SNP’s
What are SNP’s?
Small stretches of DNA that differ in only one base
SNP Frequency
Frequency: 1 in 1,000 bases to 1 in 100-300 bases
Whatdo SNP’s distinguish?
Serve to distinguish individual genetic material
How many SNP’s have been discovered? Are SNP’s common?
Millions of SNPs have been discovered
SNPs comprise ~80% of known polymorphisms
Most common type of genetic variation among people
How many SNPS in a gene?
Each gene: ~5 coding SNPs
Importance of SNPS’s
Important in understanding the genetic basis of human diseases
Relationships between SNPs and drug response