Download Blood Types, incomplete dominance

Human Traits
Environmental Factors
• Debate Nature vs. Nurture?
– BOTH!
• Environmental factors affect genes, but are
NOT inherited.
– i.e. Body type
• Genes for body type
• Exercise & diet impact body type (environment)
Multiple Alleles
• A gene that has 3 or more alleles
• Codominance: both alleles are expressed in a
heterozygous condition
– Type AB blood
• Blood Groups
– Four types are determined by the presence or
absence of a specific chemical substance
Blood Types
Types
Genotype
Antigen (ID marker) Antibody
A
I AI A
A antigen
B
A
I Ai
A antigen
B
B
IBIB
B antigen
A
B
IBi
B antigen
A
AB (universal
receiver)
I AI B
A & B antigen
-----------------------
O (universal donor)
ii
----------------------
A&B
Blood Transfusions & Transplants
• Need to be correct
• Wrong type can cause a violent or fatal
reaction in the body
LE 9-13
Blood
Group
(Phenotype)
Genotypes
Antibodies
Present in
Blood
O
ii
Anti-A
Anti-B
A
IA IA
or
IA i
Anti-B
B
IBIB
or
IBi
Anti-A
AB
IA IB
Reaction When Blood from Groups Below Is Mixed with
Antibodies from Groups at Left
O
A
B
AB
Polygenic Traits
• Controlled by a number of genes
– Height, weight, skin color