When Something Goes Wrong… A Look at Genetic Disorders

Principles of Inheritance Pedigree chart (P. 206) -Used to show patterns of trait transmission in a family. HCM - hypertrophic cardiomyopathy

Types of Inheritance A Human chromosome set can be broken into two groups: 1. Sex chromosomes X & Y 2. Autosomes The other 22 pairs! All 46 can be analyzed using a Karotype

Types of Inheritance Autosomal Recessive Inheritance Both parents heterozygous Trait may skip a generation Males and females affected equally Eg. Light eye colour & Albinism

Types of Inheritance 2. Autosomal Dominant Inheritance ½ of children of affected parent are expected to be affected. Trait does not skip generations. Males and Females affected equally. Eg. Dark eye colour, Huntington’s Disease.

Types of Inheritance 3. X-Linked Recessive Inheritance Recall (from yesterday)… Mostly males! Trait skips generations Eg. Colour blindness, Hemophilia TRY THIS! “Tracking the Hemophilia Gene” worksheet

Genetic Disorders Are the result of Mutations… A change in the genetic code. Most are recessive alleles so harmful effects are masked by a dominant gene. Visible health problems at birth are called “congenital defects”. The defects can be a result of genetic and environmental factors.

Genetic Diseases – P. 205 Two Types: Single Gene defect -Sickle Cell anemia -Cystic Fibrosis -Huntington’s Disease -Muscular Dystrophy -Hemophilia -Colour blindness Chromosomal defect -Cri-du-chat syndrome -Fragile X -Down Syndrome -Klinefelter & Turner Syndromes

Single Gene Defects

Chromosomal Defects

Homework! Page 200 #1, 5 Page 209 #1,2,3,5

A look at DNA Technology CSI Explained A look at DNA Technology

Be a “Genetic Detective”… TRAIT YOUR PHENO GENO MOM’S DAD’S SISTER #1 d D

Be a “Genetic Detective”… Solution TRAIT YOUR PHENO GENO MOM’S DAD’S SISTER #1 d dd D Dd Dd or DD

DNA Technology DNA profiling uses Gel Electrophoresis to compare DNA samples to “find a match”.

Gel Electrophoresis Most genes are similar among people. However, our ‘Junk’ DNA is different. Therefore we all have a unique DNA sequence or ‘DNA fingerprint’. Except for identical twins of course!

Gel Electrophoresis A slab of agarose gel is hooked up to a power source. The DNA sample is treated with restriction enzymes to cut it into pieces of varying lengths. (These lengths are different in everyone)

Gel Electrophoresis The DNA sample is placed the negative end of the gel and migrates towards the positive end. Small pieces move faster and farther through the gel than larger ones. This creates a unique pattern for an individual. The pattern is transferred to an X-ray film. Look for a MATCH!

I’ll see you in court…

DNA databases… Who’s DNA should be included?

DNA Extraction LAB