PBS 2.2.3

Genes are inherited - passed from one generation to the next

The genes we inherit compose our genotype - determine physical characteristics we possess - our phenotype

For every gene → two copies from sperm and egg

Alleles - variations in genes

Dominant gene - stronger gene - capital letters

Recessive gene - weaker gene - lowercase letters

Dominant gene masks recessive gene

Homozygous - 2 identical alleles for trait

Heterozygous - 2 different alleles for trait

Pedigree - diagram that shows occurence of phenotypes throughout several generations of genetically related individuals

Doctor looks at generation history to notice inheritance patterns → predict risk in future generations
Symbols represent individual
No trait → not filled in
Carrier → half filled in
Express trait → fully filled in
Generations on different lines and connections between people signified by lines

Inheritance Patterns - different ways genes are inherited

Dominant Inheritance Pattern - homozygous dominant parent →100% chance to pass off to children

Recessive Inheritance Pattern - heterozygous parents both pass recessive gene

Autosomes - identification numbers for different human chromosomes

Sex Chromosomes - not numbered, either XX or XY, determines gender

All cells have 46 chromosomes except for sex cells that have 23

Autosomal Dominant - only one mutated allele required for symptoms

Autosomal Recessive - two mutated cells required for symptoms

Punnett Square - graphical way of discovering potential genotype combinations in offspring

Familial Hypercholesterolemia (FH) - autosomal dominant

Causes LDL (”bad” cholesterol) increase → atherosclerosis → narrowing of arteries