Download Genetics and Intelligence

Genetics and Intelligence I
Genes & Heritability
What does it mean for
something to be
genetically
controlled?
Hemoglobin
• Red blood cells
• Oxygen carried by the
protein hemoglobin
Hemoglobin is a protein
• Complex molecule made of smaller units
called amino acids
• Amino acids make peptide chains
• Chains bend and fold into 3 dimensions to
make protein (e.g. myoglobin below).
• Proteins are essential to all of life
» Catalyze reactions
» Structural proteins
» Cell signaling, immune responses, cell adhesion
DNA
• DNA can be thought of as a list of recipes for
how to line up amino acids into proteins
• DNA made of nucleotides
– Adenine, Cytosine, Thymine, Guanine (ATCG)
– DNA in cells is strings of nucleotides
that sit together on chromosomes
– Nucleotides read in threes
– Segments of strings that code for
protein called genes
DNA and Genes and Proteins
(protein recipe, list of “amino acid ingredients”)
One wrong nucleotide and you get a different
amino acid, potentially big effect on protein
Sickle Cell Anemia
A trait with strong genetic control
• C738H1166N812O203S2Fe
• Hemoglobin folds and fits
into RBC and carries
oxygen
• But, a mistake in
nucleotide sequence (the
gene/recipe) and
hemoglobin doesn’t fold
right.
Sickled cells block blood vessels
body suffocates with long-term, severe
consequences, death
Phenylketonuria (PKU)
• Body lacks ability to metabolize
phenylketones
• Recessive genetic disorder causes
seizures, retardation, etc.
• Every child tested at birth
• Can be controlled through diet
Recessive genetic disorder?
You have two copies
of each gene
1 from mom, 1 from
dad
The Cancer Gene
Press Releases Sloan-Kettering
New Cancer Gene Identified
• Oncogene Plays a Critical
Role in Tumor Formation
• January 20, 2005
•
• NEW YORK - Scientists at
Memorial Sloan-Kettering
Cancer Center (MSKCC) have
identified a new cellular
oncogene essential for the
development of cancer…..
• But, lung cancer, one of
leading cause of diseases
in USA, is over-whelming
caused by smoking
• People who have never
smoked and die of lung
cancer exist, but they are
a small fraction of those
who get lung cancer
The Gene for…..
Some genes seem to be more prevalent in
people with certain behavioral traits, such
as schizophrenia, manic-depression,
compulsive gambling, alcoholism,
homosexuality
?? What does this mean??
Genes + Environment = Phenotype
Genetics or Free Will?
• Atoms make up molecules, molecules
make up DNA-chromosomes-genesproteins
• Proteins make the world go ‘round’
• So at some level, everything is governed
by our genes, but does that mean
organisms have no free will?
Single Gene Traits
Rare but cool examples can be found
Hygienic behavior in
bees- behavior
controlled two genes
Bees recognize and cut
out infected and dead
brood. Protects
against foulbrood,
chalkbrood and now
Varroa mites
10% presence naturally
Dancing bees
Dancing tell nest mates
location of resources
Waggle Dance
Dance type is caused
by single gene and
species specific
Genetic Expression: the plot thickens
and the story gets complicated
1) Pleiotropy- one gene, multiple effects
2) Incomplete Dominance- pink carnations
3) Environmental Effects- heat, pH, drought
4) Epistasis- many genes interact to affect
one trait (human height)
5) Codominance- multiple genes control
single trait (e.g. ABO blood group)
This is a Major Frontier of Science: the dynamics between
genes and environment
Blood groups (codominance)
• Three possibilities of blood type
–
–
–
–
–
–
AA, AO Type A (can receive from A and O)
AB Type AB (can receive from A, B, AB or O)
BB, BO Type B (can receive from B and O)
OO Type O (and only receive from O)
O is universal donor because it doesn’t elicit attack from A or B
AB is universal recipient because it doesn’t attack anything
A and B are codominant; O is recessive to both
Genetics and Human Intelligence
We will be looking at the following:
• How has human intelligence been studied?
• How do science and politics mingle in the
conscious and unconscious minds of scientists?
• Does ‘genetic basis for intelligence’ mean same
thing as born ‘smart’ or ‘dumb’?
• What is race?
• What is intelligence?
• Debate: Can intelligence be measured in a
meaningful way?