Genetics and Health Jennifer Eyvindson Epi 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-dominance AA 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 DNA 2. tRNA binds to mRNA- Ribosome complex and brings Amino Acid 3. Amino Acid chain elongation 4. Protein These Molecular Processes are highly regulated: Promoters Inducers Repressors *Environment Influence

Protein Functions  Structure & Mechanics Cell Structure Transport  Enzymes Catalyze chemical reactions  Signalers Hormones Receptors

When things go wrong DNA  Deletion  Insertion  Point mutation PROTEIN  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 genes and their interactions  Laws and Ethics Genetic profiles ???