Genetics and Health

Jennifer EyvindsonEpi 6181 November 2006

Points to cover

Basic Genetics Heredity Replication Translation Mutations

Genetics and Health Cancer Genes, behaviour, & social environment Tools to develop

Heredity

Allele – a particular form of a gene

We have 2 copies of each gene Homozygous – 2 copies of same allele

Heterozygous – 2 different alleles

Dominant (A) vs. Recessive (a)

Incomplete Dominance

Co-dominanceAA Aa aa

The basics

Chromosomes Condensed DNA Located in Nucleus

DNA Blueprint

The Double Helix Watson and Crick (1953)

2 Strands of DNA Hydrogen bonds

Overview – Genetic processes

Transcription (DNA RNA)

Translation (RNA Protein )

Replication (DNA DNA)

DNA Replication

DNA must be copied before every cell division

Translation (protein synthesis)

1. Ribosome binds to DNA2. tRNA binds to mRNA-

Ribosome complex and brings Amino Acid

3. Amino Acid chain elongation4. Protein

These Molecular Processes are highly regulated:

PromotersInducersRepressors

*Environment Influence

Protein Functions Structure & Mechanics

Cell Structure

Transport

Enzymes Catalyze chemical reactions

Signalers Hormones

Receptors

When things go wrong

DNA Deletion Insertion Point mutationPROTEIN Non-sense (STOP) Mis-sence Silent

It’s not that simple…

Human Genome Project (April 2003) map and sequence 3 billion DNA base pairs

containing an estimated 30,000 genes 97% Non-coding “JUNK” DNA

Polygenetic Inheritance Most traits result from expression of more than

one gene Gradients Complex interactions not well understood

Genetics and Health Inherited

Disorders Allele (Huntington's) X-linked (Hemophilia)

Other predispositions Allele variants (Addictions, Depression, Cancer…

etc)

Errors Cancers Chromosomal abnormalities (Down syndrome)

The Genetics of Cancer

Tumours are the result of multiple mutations

Mutations can be inherited or de novo Genetic Loss

Regulatory Apoptosis (Cell self destruct mechanism) DNA repair

Genetic Gain Cell Cycle progression Apoptosis inhibitors

Genes, Behaviour, and the Social Environment

Top Down Social factors influence genetics

Environmental mutagens lead to DNA mutations and cancer

Environment regulates gene expression

Bottom up Genetics influence behaviors, thereby

the social environment Inherited traits predispose individuals to

act in certain ways

Tools to develop

Bio Technology Look at multiple genes, proteins

Informatics Keep track of 30 000 genes and their

interactions

Laws and Ethics Genetic profiles ???