bailee ludwig quality management. before we get started…. ….let’s see what you know about...
TRANSCRIPT
An Introduction to Genomics and Personalized Health Care
Bailee Ludwig
Quality Management
Before we get started….
….Let’s see what you know about Genomics
DNA You may have heard that DNA is the blueprint for
life…but what does that mean exactly?
Essentially…
DNA (Genes) Protein Cells People
That seems simple enough, right? Unfortunately it’s a little more complicated than that. Let’s start at the beginning…
What exactly is DNA? DNA =Deoxyribonucleic Acid
A helical molecule comprised of 2 polymer strands (each of which is comprised of a sequence of four nucleotides (bases) )
The Four Base Pairs
2 Purines
Adenine (A)
Guanine (G)
2 Pyrimidines
Thymine (T)
Cytosine (C)
Adenine (A) pairs with Thymine (T)
Guanine (G) pairs with Cytosine (C)
Hydrogen Bonds
Sugar – Phosphate “Backbone
”
Nucleotide “Bases”
DNA SequencingA DNA sequence
can be either single-stranded
or double-stranded
DNA sequences have an
orientation: from 5’ to 3’ or from 3’
to 5’ (chemical conventions)
What is RNA? RNA = Ribonucleic Acid
A single-stranded molecule
It is comprised of four nucleotides
A, C, G, and U (Uracil)
Different types of RNAs
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
Uracil
DNA RNA Protein
DNA RNA Protein
Transcription Translation
Central Dogma of Molecular Biology
TranscriptionDNA RNA
RNA is Produced by copying one of the two strands of a DNA molecule in the 5’ to 3’ direction in a process called DNA Transcription
In DNA Transcription…
RNA molecules synthesized by RNA polymerase enzyme
RNA polymerase binds to promoter region on DNA
Promoter region contains start site
Transcription ends at termination signal site
Splicing & Alternative Splicing RNA splicing: introns removed to make the mRNA
Intron – the part of a gene that is NOT translated to a protein
Exon – the part of the nucleic acid that remains after introns are removed
mRNA: contains the sequence of codons that code for a protein
Alternative splicing – when the remaining exons reconnect to form different mRNAs
Also know as Post-transcriptional modification
Pre mRNA Mature mRNA
TranslationRNA - Protein
Ribosomes are made of protein and rRNA (ribosomal RNA)
mRNA goes through the ribosomes
Initiation factors: proteins that catayze the start of transcription
tRNA brings the different amino acids to the ribosome complex so that the amino acids can be attached to the growing amino acid chain
When a STOP codon is encountered, the ribosome releases the mRNA and synthesis ends
An open reading frames (ORF): a contiguous sequence of DNA starting at a start codon and ending at a STOP codon
http://www.youtube.com/watch?v=5bLEDd-PSTQ
Check out this video for a great summary of Translation…
Genes Gene = A stretch of DNA containing the information necessary for
coding a protein/polypeptide
Promoter region
Transcription Factor Binding Site
Translation Start Site
Exon: coding (informative) regions of the DNA
Intron: noninformative regions between exons
Untranslated region (UTR)
Codons
ProteinDNA RNA Protein
Protein - A molecule comprising a long chain of amino acids connected by peptide bonds
There are 20 standard amino acids encoded by the universal genetic code
Cell Types
Prokaryotes: a group of organisms that lack of nucleus membrane, such as blue-green algae and common bacteria (Escherichia coli)
It has two major taxa: Archaea and Bacteria
Eukaryotes: unicellular and multicellular organisms
Ex. yeast, fruit-fly, mouse, plants, and human
Eukaryotes In eukaryotes, transcription is complex:
Many genes contain alternating exons and introns
Introns are spliced out of mRNA
mRNA then leaves the nucleus to be translated by ribosomes
Genomic DNA: entire gene including exons and introns
The same genomic DNA can produce different proteins by alternative splicing of exons
Complementary DNA (cDNA): spliced sequence containing only exons
cDNA can be manufactured by capturing mRNA and performing reverse transcription
Eukaryotic Gene Structure
Chromosomes A chromosome is a long and tightly wound DNA string
(visible under a microscope)
Chromosomes can be linear or circular
Prokaryotes usually have a single chromosome, often a circular DNA molecule
Chromosomes (2) Eukaryotic chromosome appear in pairs (diploid),
each inherited from one parent
Homologous chromosomes carry the same genes
Some genes are the same in both parents
Some genes appear in different forms called alleles, e.g., human blood type has three alleles: A, B, and O
All genes are presented in all cells, but a give cell types only expressed a small portion of the genes
Genomes
The genome is formed by one or more chromosomes
A genome is the entire set of all DNA contained in a cell
A human genome has 46 chromosomes
The total length of a human genome is 3 billion bases
Genome Sequences
Species CompleteDraft Assembly
(Almost complete)In process Total
All 1003 1360 1336 3699
Eukaryotes 22 218 156 396
Phage phiX174 5,368
HIV virus 9,193
SARS 29,751
Haemophilus influenzae (bacteria) 1,830,000
Escherichia coli K12 4,600,000
Saccharomyces cerevisiae (yeast) 12,500,000
Drosophila melanogaster (fruit fly) 180,000,000
Arabidopsis thaliana (thale cress) 125,000,000
Homo sapiens (human) 3,000,000,000
Genome Sequence SizesDNA Sequence size is measured as base pairs (bp)
The Whole Picture
Let’s summarize what we’ve covered today with a Video….
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I’m sure right now you’re thinking…
This review of Bio 1 has been wonderful, but how
does it apply to HIM??
Did you know..? In a few short years, mapping a persons
genome will be a routine hospital test
A Genome can reveal not only an individuals health information, but also the health information of their family
A Genome in the ‘wrong hands’ can lead to Genetic Discrimination
Genetic Discrimination can prevent people from obtaining health insurance and jobs
As HIM Professionals…You will be responsible for storing this
highly sensitive information in a Secure, Private, and
Confidential Manner
You will be implementing new storage options…most Electronic Health Records are not prepared to store a genome
Next Lecture…We will talk more in depth about
Genomic Security
Genomic Ethics
Genetic Law
Risk Perception and Health Behavior
Genomic Responsibility
