Chapter 4: Genetics, Evolution, Development, and Plasticity (In Class Notes)
1. Genetics and Evolution of Behavior
i) Overview:
(1) Mendel (19th century): inheritance occurs through genes
(2) Plant hybridization = foundation of modern genetics
(a) Early writer on evolutionary theory (Charles Darwin)
(3) Genes = most basic heredity basic unit that holds that maintains structured
unity, long stretch of DNA (coding for proteins)
(a) Pieces of DNA
(b) Like sentences (DNA is the book of you, gene is a sentence(makes up your
book)
(c) We humans have 20,000 (happy genes are that produce proteins)
(d) Fruit fly: 12,000 genes (we humans share a lot in common)
(4) Chromosomes are strands of genes, normally in PAIRS (at least when they
divide and reproduce)
(5) Genotype: notation of a gene pair (BB, Bb, bb, blue-eyed, brown-eyed
example)
(6) Phenotype: expression of the gene
ii) Video shown notes:
(1) DNA
(2) Gene
(3) Mutation: any change in nucleotide sequence with DNA (passed down from
parent to child)
(4) Chromosomes: unraveled by a thread
(5) Chromosomes: are only tight when reproduction
iii) Sex-Linked Genes
(1) 23rd pair (sex chromosomes)
(2) Cannot drive at night (X chromosome)
(3) Color blindness (most common)
(4) Hemophilia
iv) Sex-Limited Genes
(1) On other 22 pairs (autosomes)
(2) Puts the DNA in order
(3) Genes that express themselves in one sex, opposed to other sex
(4) Genes in men and female, shown in one sex
(5) In both sexes, but effect mostly limited to one sex
(a) Example: Facial hair (shown majority on men, but women has it and
doesn’t express yourself)
(b) Example: Breast development: females normally have these, men never
express themselves
, (c) Example: Back hair (men normally have testosterone for a lot, while
females do not normally go through this or experience this much hair, but
can)
(i) Take testosterone at high levels overtime (female if you wanted to
know if you have back hair gene like your brothers)
(d) Genes expressed only after activation by sex hormones
(e) Could come from either parent, both parents
(f) Male pattern baldness is a sex-limited trait
(g) Both males and females possess the genes
(h) The genes are “turned on” by androgens
(i) DHT (5%) in the body: receptor in hair follicle (you can stop DHT by oral
pills, hair loss will stop and grow up): could effect a drawback of the
oral pill, drops the DHT to drop low
(ii) As test increasing, DHT is a biproduct with metabolism (chokes the hair
and hair falls out, leads to 0 hair)
(iii) Sex-limited genes EXAMPLE ^^^ (maybe on exam, older women, not
normally younger)
(i) Taking hormones will alter how your genes are expressed
(i) Example in class: Photos are across 3 years while taking hormones for
gender alignment (man, half man/half women, woman)
(ii) If you choose to do this, you have to keep taking the hormones forever
or you will originate back to normal? ******
2) Nature vs Nurture
a) Old question… still no absolute answers
b) Recent studies seem to indicate a false dichotomy
c) The environment can affect appearance
i) Example: Flamingos are pink when they eat shrimp, turn from white to pink
d) Epigenetics: more recent discover
i) Phenotype changes WITHOUT no DNA sequence change
ii) Are heritable! (a lot of different generations)
iii) Genes are turned off or on for generations
iv) Environment has some involvement
e) Video on Epigenetics:
i) DNA gets passed to offspring
ii) How the code was read in the bodies
iii) Chemicals switches turn on and off
iv) Rats (getting put in the box and later on generations were aware of the “shock”
that happened, even if they did not experience it)
f) Variable expressivity
1. Genetics and Evolution of Behavior
i) Overview:
(1) Mendel (19th century): inheritance occurs through genes
(2) Plant hybridization = foundation of modern genetics
(a) Early writer on evolutionary theory (Charles Darwin)
(3) Genes = most basic heredity basic unit that holds that maintains structured
unity, long stretch of DNA (coding for proteins)
(a) Pieces of DNA
(b) Like sentences (DNA is the book of you, gene is a sentence(makes up your
book)
(c) We humans have 20,000 (happy genes are that produce proteins)
(d) Fruit fly: 12,000 genes (we humans share a lot in common)
(4) Chromosomes are strands of genes, normally in PAIRS (at least when they
divide and reproduce)
(5) Genotype: notation of a gene pair (BB, Bb, bb, blue-eyed, brown-eyed
example)
(6) Phenotype: expression of the gene
ii) Video shown notes:
(1) DNA
(2) Gene
(3) Mutation: any change in nucleotide sequence with DNA (passed down from
parent to child)
(4) Chromosomes: unraveled by a thread
(5) Chromosomes: are only tight when reproduction
iii) Sex-Linked Genes
(1) 23rd pair (sex chromosomes)
(2) Cannot drive at night (X chromosome)
(3) Color blindness (most common)
(4) Hemophilia
iv) Sex-Limited Genes
(1) On other 22 pairs (autosomes)
(2) Puts the DNA in order
(3) Genes that express themselves in one sex, opposed to other sex
(4) Genes in men and female, shown in one sex
(5) In both sexes, but effect mostly limited to one sex
(a) Example: Facial hair (shown majority on men, but women has it and
doesn’t express yourself)
(b) Example: Breast development: females normally have these, men never
express themselves
, (c) Example: Back hair (men normally have testosterone for a lot, while
females do not normally go through this or experience this much hair, but
can)
(i) Take testosterone at high levels overtime (female if you wanted to
know if you have back hair gene like your brothers)
(d) Genes expressed only after activation by sex hormones
(e) Could come from either parent, both parents
(f) Male pattern baldness is a sex-limited trait
(g) Both males and females possess the genes
(h) The genes are “turned on” by androgens
(i) DHT (5%) in the body: receptor in hair follicle (you can stop DHT by oral
pills, hair loss will stop and grow up): could effect a drawback of the
oral pill, drops the DHT to drop low
(ii) As test increasing, DHT is a biproduct with metabolism (chokes the hair
and hair falls out, leads to 0 hair)
(iii) Sex-limited genes EXAMPLE ^^^ (maybe on exam, older women, not
normally younger)
(i) Taking hormones will alter how your genes are expressed
(i) Example in class: Photos are across 3 years while taking hormones for
gender alignment (man, half man/half women, woman)
(ii) If you choose to do this, you have to keep taking the hormones forever
or you will originate back to normal? ******
2) Nature vs Nurture
a) Old question… still no absolute answers
b) Recent studies seem to indicate a false dichotomy
c) The environment can affect appearance
i) Example: Flamingos are pink when they eat shrimp, turn from white to pink
d) Epigenetics: more recent discover
i) Phenotype changes WITHOUT no DNA sequence change
ii) Are heritable! (a lot of different generations)
iii) Genes are turned off or on for generations
iv) Environment has some involvement
e) Video on Epigenetics:
i) DNA gets passed to offspring
ii) How the code was read in the bodies
iii) Chemicals switches turn on and off
iv) Rats (getting put in the box and later on generations were aware of the “shock”
that happened, even if they did not experience it)
f) Variable expressivity
