CUMULATIVE pre-lecture reading and textbook notes for chapters 1-10 of the class BIOLOGY305: Genetics at the University of Michigan. Notes taken WN2024 under professors Andrej Wierzbicki and Delbert Green
Lecture
1:
The
Genetic
Approach
to
Biology
Pre-Lecture
Notes
Detective
Work:
Figuring
Out
What
Genes
Do
●
Genes
carry
essential
genetic
information
○
Geneticists
try
to
figure
out
what
particular
genes
do
and
how
they
affect
the
organism
as
a
whole
●
Human
genome:
~20,000
protein-coding
genes,
~63,000
total
genes
●
Gene
discovery:
search
for
genes
w/
specific
functions
●
Method
(called
forward
genetics
):
choose
a
phenotype/character/trait
of
interest,
search
for
genes
that
affect
that
trait
○
Usually
start
by
comparing
wild-type
individual
to
variant
using
genetic
crosses
●
Modern
tech
+
long
history
of
research
→
complete
genome
sequences
available
for
humans
and
other
species
→
another
method
is
to
choose
an
unknown
piece
of
DNA
and
work
backwards
to
see
how
it
affects
an
organism
(
reverse
genetics
)
●
Mutations
appear
spontaneously
in
the
wild
○
If
variant
individual
is
rare,
called
mutant
or
mutation
○
Mutants
can
also
be
created
in
lab
using
mutagenesis
,
where
organism
is
exposed
to
environment
that
will
speed
up
rate
of
DNA
mutation
●
Mutants
studied
in
order
to
determine
consequences
of
altering
a
gene,
to
follow
gene
inheritance
b/n
generations
○
When
disrupted
gene
in
a
mutant
is
identified,
usually
named
for
the
mutant
phenotype
■
Ex:
gene
disrupted
in
flies
that
lack
wings
is
called
wingless
●
Genetic
dissection:
gene
discovery
using
collections
of
mutants
that
affect
trait
of
interest
Tools
for
Genetic
Analysis
●
Gel
electrophoresis:
uses
electric
field
to
separate
DNA,
RNA,
or
protein
pieces
by
size,
shape,
charge
●
Band:
molecules
of
same
size
appear
as
a
band
in
the
gel
○
Assumes
that
there
are
many
copies
of
the
molecule
○
Single
molecule
can’t
be
depicted
in
the
gel
●
Ladder:
reference
sample
for
which
the
sizes
of
the
molecules
are
known
●
Polymerase
Chain
Reaction
(PCR):
method
that
allows
for
copying/amplifying
specific
DNA
sequences Chapter
1:
The
Molecular
Basis
of
Heredity,
Variation,
and
Evolution
1.1
Modern
Genetics
Is
in
Its
Second
Century
●
Germ
Plasm
Theory:
reproductive
organs
carry
full
sets
of
genetic
info
w/in
the
sperm/egg
cells,
which
are
brought
together
in
fertilization
●
Four
phases
of
modern
genetics:
○
Identification
of
cell/chromosome
basis
of
heredity
○
Identification
of
DNA
as
hereditary
material
○
Description
of
informational/regulatory
processes
of
heredity
■
Encoding
info
in
genes
■
Transcription/translation
○
Genomic
era
■
Current
■
Began
in
80s
w
completing
first
genome
sequences,
continues
to
now
●
Genes:
physical
units
of
heredity
○
Made
up
of
DNA
sequences
that
contain
info
to
produce
RNA
molecules
●
Chromosomes:
long,
single
molecules
of
double-stranded
DNA
bound
by
many
kinds
of
proteins
○
Chromosomes
in
sexually
producing
organisms
usually
are
in
homologous
pairs
(homologs)
○
Carries
many
genes
●
Bacteria
and
archaea
have
one
circular
chromosome
→
only
one
copy
of
each
gene
in
in
the
genome
(condition
called
haploid
)
○
Bound
by
small
amount
of
protein
●
Eukaryotes
have
a
true
nucleus
w
multiple
sets
of
chromosomes
○
Have
haploid
and
diploid
stages
in
life
cycle
■
Sperm
and
eggs
are
haploid,
combined
they
are
diploid
■
In
diploid
stage,
genome
has
2
copies
(a
homologous
pair)
of
each
gene
○
Some
genomes
(particularly
plants)
have
more
than
2
copies
of
each
chromosome
–
called
polyploidy
●
Plants
and
animals
also
have
genetic
material
in
their
mitochondria
,
specialized
organelles
○
Plants
also
have
genes
in
their
chloroplasts
○
Organelle
genes
produce
proteins
that
perform
important
tasks
●
Cytoplasmic
Inheritance:
refers
to
random
distribution
of
mitochondria/chloroplasts
among
daughter
cells
○
Organelles
are
transmitted
in
cytoplasm
during
cell
division
●
Mitosis:
complete
set
of
chromosomes
transmitted
○
Produces
genetically
identical
daughter
cells
●
Meiosis:
process
in
sexual
reproduction,
produces
sex
cells
(
gametes
)
●
Alleles:
alternative
forms
of
a
gene
that
alter
the
phenotype
●
Genome:
complete
set
of
DNA
sequences ○
Genes,
regions
controlling
those
genes
●
LUCA:
last
universal
common
ancestor
○
All
three
domains
(
eukarya,
bacteria,
archaea
)
evolved
from
LUCA
●
Foundations
of
modern
bio:
○
All
life
on
earth
shares
common
ancestor
(LUCA)
○
DNA
is
hereditary
material
in
all
organisms
●
All
3
domains
share
general
mechanism
of
DNA
replication
and
gene
expression
○
All
organisms
use
transcription
and
translation
■
Transcription:
one
strand
of
DNA
synthesizes
one
strand
of
RNA
■
Translation
:
RNA
codes
for
protein
production
at
the
ribosomes
●
3
branches
of
modern
genetics:
○
Transmission
(Mendelian)
:
transmission
of
traits
in
successive
generations
○
Evolutionary
:
origins
of
and
genetic
relationships
b/n
organisms;
evolution
of
genes/genomes
○
Molecular
:
inheritance
and
variation
in
DNA,
RNA,
proteins,
and
genomes
1.2
Structure
of
DNA
Suggests
a
Mechanism
for
Replication
●
Chargaff’s
Rule:
percent
of
adenine
and
thymine
are
approx.
equal,
and
percent
of
cytosine
and
guanine
are
approx.
equal
○
Helped
form
hypothesis
that
DNA
nucleotides
are
arranged
in
complementary
base
pairs
●
Each
strand
in
the
helix
is
made
of
DNA
nucleotides
w/
3
principle
pieces:
5-carbon
deoxyribose
sugar,
a
phosphate,
and
one
of
4
nitrogen-containing
nucleotide
bases
(A,
C,
T,
or
G)
○
Nucleotides
are
linked
by
a
covalent
phosphodiester
bond
b/n
the
5’
phosphate
group
of
one
nucleotide
and
the
3’
hydroxyl
group
of
the
adjacent
nucleotide
■
This
bond
→
alternating
deoxyribose
sugars/phosphate
groups
on
the
strand
→
sugar-phosphate
backbone
●
Nucleotide
bases
are
hydrophobic
●
Hydrogen
bonds
form
between
the
base
pairs
to
join
two
DNA
strands
into
a
double
helix
○
Two
hydrogen
bonds
for
A–T,
three
for
C–G
●
Each
DNA
strand
has
a
5’
and
a
3’
end
to
establish
strand
polarity
○
Complementary
strands
of
DNA
are
antiparallel
,
so
the
3’
end
of
one
strand
is
matched
with
the
5’
end
of
the
other
●
Semiconservative
Replication:
usual
DNA
replication
mechanism,
the
two
complimentary
helix
strands
separate
and
each
strand
acts
as
a
template
for
a
new
complimentary
strand
○
Each
new
helix
has
a
parental
strand
and
a
new
daughter
strand
●
DNA
only
replicates
in
the
5’-to-
3’
direction 1.3
DNA
Transcription
and
Messenger
RNA
Translation
Express
Genes
●
Central
Dogma
of
Biology:
statement
describing
flow
of
hereditary
info
and
other
central
aspects
of
DNA
and
inheritance
○
Modern
bio
has
clear
understanding
of
the
central
dogma
○
●
Multiple
types
of
RNA
○
Ribosomal
RNA
(rRNA)
:
NOT
translated,
forms
part
of
the
ribosomes
○
Transfer
RNA
(tRNA)
:
NOT
translated,
carries
amino
acids
(building
blocks
of
proteins)
to
the
ribosomes
○
Messenger
RNA
(mRNA)
:
translated
to
make
proteins
●
Reverse
Transcription:
form
of
information
flow
where
an
enzyme
synthesizes
DNA
from
an
RNA
template
that
comes
from
RNA-containing
viruses
Transcription
●
Transcription
:
process
by
which
DNA
info
is
converted
into
an
RNA
sequence
●
Template
Strand:
strand
of
DNA
that
synthesizes
the
transcript
○
RNA
polymerase
pairs
template-strand
nucleotides
w/
their
pair
RNA
nucleotides
●
RNA
uses
uracil
(U)
instead
of
thymine,
which
still
pairs
with
adenine
●
To
begin
transcription,
RNA
polymerase
and
other
necessary
proteins
locate
a
gene,
access
template
strand
by
interacting
with
DNA
sequences
that
initiate
transcription
○
RNA
polymerase
also
ends
transcription
and
releases
transcript
at
the
end
●
Promoters:
most
common
DNA
sequence
controlling
transcription
○
Recognised
by
RNA
polymerase
which
directs
them
to
nearby
gene
○
Not
transcribed
by
RNA
polymerase
●
Eukaryotic
genes
divided
into
exons
which
have
all
the
coding
information
for
translation,
and
introns
which
intervene
between
exons
and
are
removed
before
translation
Translation
●
Translation
:
conversion
of
genetic
info
in
mRNA
into
amino
acid
sequences
●
Amino
acids
joined
together
by
covalent
peptide
bond
,
and
they
string
together
to
form
polypeptides
○
Folded
up
polypeptides
→
proteins
(one
or
more
polypeptides
combined)
●
Translation
occurs
in
the
ribosomes
●
Codon:
set
of
3
consecutive
nucleotides
in
mRNA
which
specify
the
amino
acid
at
each
position
in
the
polypeptide
●
To
begin,
mRNA
attaches
to
ribosome
in
a
way
that
puts
the
start
codon
in
the
right
location
Les avantages d'acheter des résumés chez Stuvia:
Qualité garantie par les avis des clients
Les clients de Stuvia ont évalués plus de 700 000 résumés. C'est comme ça que vous savez que vous achetez les meilleurs documents.
L’achat facile et rapide
Vous pouvez payer rapidement avec iDeal, carte de crédit ou Stuvia-crédit pour les résumés. Il n'y a pas d'adhésion nécessaire.
Focus sur l’essentiel
Vos camarades écrivent eux-mêmes les notes d’étude, c’est pourquoi les documents sont toujours fiables et à jour. Cela garantit que vous arrivez rapidement au coeur du matériel.
Foire aux questions
Qu'est-ce que j'obtiens en achetant ce document ?
Vous obtenez un PDF, disponible immédiatement après votre achat. Le document acheté est accessible à tout moment, n'importe où et indéfiniment via votre profil.
Garantie de remboursement : comment ça marche ?
Notre garantie de satisfaction garantit que vous trouverez toujours un document d'étude qui vous convient. Vous remplissez un formulaire et notre équipe du service client s'occupe du reste.
Auprès de qui est-ce que j'achète ce résumé ?
Stuvia est une place de marché. Alors, vous n'achetez donc pas ce document chez nous, mais auprès du vendeur gloriakawai. Stuvia facilite les paiements au vendeur.
Est-ce que j'aurai un abonnement?
Non, vous n'achetez ce résumé que pour 18,91 €. Vous n'êtes lié à rien après votre achat.