Transcript Ontogenetics Notes

OntoGenetics
Nature vs. Nurture
Hair color
Skin color
freckles
Widows peak
Eye color
Deoxyribonucleic Acid
• DNA means ______________________
chromosomes
• Make up your ____________________.
genes
– Consists of many _____________
that
traits
genetically code for each of your _________.
What happens if the “code” fails or is
changed???
Mutation
______________________
Copies DNA gene code
PROTEIN that makes your
eyes blue!!
Determines everything else!!
• Located on the sex chromosome (usually the X since it’s
much larger than the Y).
• Called “sex-linked” genes
• popular examples are Color Blondness, Fragile X
syndrome, Mucular Dystrophy, and Hemophilia
Mom
Dad
MALE
FEMALE
Determines NOT
ONLY SEX, but also
many sex
characteristics!!
Mom
Dad
Color
Blindness
Carrier female
Normal male
Carrier Female
Normal male
Why can Dad NOT pass on the defect to his sons???
Mom
Dad
Color
Blindness
Carrier female
Effected male
Normal Female
Normal male
Which gender does Mom pass the defect on to??
• A female with a defected X has a 2nd
“good X” to compensate for the problem
• A male, on the other hand, only has one X,
so if he gets a defected one, he’s stuck
with the disorder!
• Males can not pass on their defect to a son. Why?
Males do not pass on an X to a son, only a Y
_____________________________________________________
What is the only way for a female to have the disorder?
If she gets 2 BAD X’s, one from each parent!
______________________________________________________
Since only men go bald, you might think the balding gene is on the sex
chromosome, but it’s not. It’s found on the 11th. Why then, don’t more
women show baldness?
Sex-Limited Genes
• Genes that are present in both sexes, but
influences only one.
• Found on autosomes (not sex), but has effect on
only one sex.
– Ex: Chest hair, baldness, and breast size in humans.
Is a trait inherited or is it learned from experience…..
NATURE vs. NURTURE
Are you a good singer because of your genes, or because you practice a lot?
Heritability is a mathematical proportion indicating the extent of
inheritance and/or the extent of non-inheritable factors (such as environment).
SCALE
100% environmental
100% inherited
“low heritability”
“high heritability”
Heritability
• Adopted children
– Resembling their adoptive parents would
indicate...
– Resembling their biological parents would
indicate…
HERITABLITY (cont.)
“Monozygotic twins ” Identical twins
(same DNA)
“Dizygotic twins” Fraternal twins
(different DNA)
Where on the heritability scale would these scenarios fall?
Strong resemblance in monozygotic twins??
High heritability
Equal resemblance in both sets of twins??
Low heritablity
Phenylketonuria (PKU)
• Genetics condition characterized by
mental retardation. It is caused by diet.
• Inability to metabolize the amino acid
Phenylalanine. It builds up to toxic levels
in people with the disorder.
• Eliminate the amino acid from the diet, and
eliminate its effects!
• It is heritable, but can be modified by
following a particular diet!!