Human Chromosomes
Karyotype = picture or pattern of chromosomes arranged in homologous pairs & organized by size (See fig. 14-1 p. 341)
Humans have 46 chromosomes
2 of these are sex chromosomes
XX = female XY = male
The other 44 chromosomes are known as autosomes

Human Trait
To study inheritance, biologists use pedigree charts

Shows relationships within a family

Many traits are strongly influenced by environmental factors (ex: height,personality)

Human Genes = Human genome

Our complete set of genetic info
Includes tens of thousands of genes

Genes controlling blood types were 1st genes to be identified
Most common ones are the ABO & the Rh blood groups ( + and - )

ABO Blood Group
Controlled by 3 alleles - A, B, O
A and B are codominant
O is recessive to both A and B
The blood type is the phenotype

Genotype Bloodtype
AA, AO = Type A
BB, BO = Type B
AB codominant = Type AB (universal recipient)
OO recessive = Type O (universal donor)

Human Genetic Disorders (See fig 14-6 p.345)
Phenylketonuria (PKU)
Tay - Sachs disease recessive
Albinism

Achondroplasia
Huntington's disease dominant

Sickle-cell disease codominant
heterozygous is resistant to malaria