Transcript P 1

Genetics 101
+
=
?
~a genetics tutorial~
_______________________
basic genetics for the non-genetecist via gerbils
for the non-rodent enthusiast
mr. e ~ SRCS ~ fall 2005
Genetics 101
Contributions and dedications
Eric Proffit
fall 2002-4
David Schulker
spring 2003-4
Stephen Potter
fall 2002-2005
Chad Peets
spring 2003-6
Christopher Oliver
winter 2004-6
John Magill
winter 2004-5
Ben Bennett
winter 2004-5
Genetics 101
macro
What happens when
you combine peas and
the church?
Genetics 101
+
Peas
=
the Church
Who: Father Johann Gregor
Mendel
Where: a monastery in Austria
What: Developed hereditary theories
When: 1850’- 1860’s (just before US civil war)
Father of
Modern Genetics
Genetics 101
•
Macro-history
• His early adult life was spent in relative Gregor Mendel
obscurity doing basic genetics research
1822-1884
and teaching high school mathematics, physics, and
Greek in Brunn (now in the Czech Republic).
• In his later years, he became the abbot of his
monastery and put aside his scientific work.
• His ideas had been published in 1866 but largely
went unrecognized until 1900, which was long after
his death.
Genetics 101
• Macro-history
Mendel's research reflected his
personality. Once he crossed peas and
mice of different varieties (separately,
that is) "for the fun of the thing," and the
phenomena of dominance and
segregation "forced themselves upon
notice."
• He saw that the traits were inherited in
certain numerical ratios. He then came up
with the idea to set out to test it more
vigorously using the common pea (Pisum
sativum).
+
?
Genetics 101
• Mendel studied seven basic characteristics of peas:
1. flower color
4. seed shape
2. flower position
5. seed color
3. stem length
6. pod shape
7. pod color
By tracing these characteristics, Mendel discovered
three basic principles which governed the passage of
a trait from one member of a species to another
member of the same species.
Genetics 101
• Mendel’s conclusions
1. that the inheritance of each trait is
determined by "units" or "factors" that are
passed on to descendents unchanged (these units
are now called genes )
2. that an individual inherits one such unit
from each parent for each trait
3. that a trait may not show up in an
individual but can still be passed on to the
next generation.
Genetics 101
So what exactly is new about all this?
Significant? Doesn’t seem so…
Genetics 101
Where would we be without…
The liger: lion X tigress
I’m Samson.
I stand 3.7 m
(12 feet) tall
on my hind
legs and
weigh 500 kg
(1,100 lbs)
and can run
at 80 km/hr
(50 mph)!
Genetics 101
.
Speciation: Is it immoral to
hybridize animals?
Ethical dilemma or freak show curiosity?
Pros vs.Cons
Should the advantages & disadvantages even be
taken into consideration?
Ethical Issues in Genetic Engineering and Transgenics
By Linda MacDonald Glenn
Genetics 101
the Cama…
I have the cloven
hooves of a llama
and the short ears
and tail of a camel!
& I can spit too!
…scientists hope to combine the best qualities of both into the one animal — the
superior fleece and calmer temperament of the llama with the larger size of the camel.
Genetics 101
The
Zonkey…
(zedonk or
The
Zorse…
Zebras, donkeys,
and horses are all
zebrass)
members of the family equus Equines. They are all slightly
different in genetic makeup, but still
all equines. Equines can be crossbred
to produce hybrids. That is, horses
have 64 chromosomes, donkeys have
62. The cross between a Donkey Jack
(Stallion) and a mare Horse is called a
Mule. The opposite cross is a
Hinny. (Mules and hinnies can be
male or female, either one, but are
sterile since their chromosome count
is 63).
Genetics 101
I’m Kekaimalu, the world’s
first and only wholphin. My
smaller mom, a bottlenose
dolphin, swims with me (below
left) while my dad, a false killer
whale is bigger & has more
teeth! I’m their average!
the Wholphin…
Genetics 101
.
What’s
Next??
Mt. Dewmaking flies?
Aquatic bovines…
Mumu?
Genetics 101
Seriously…
better
yielding
crops
Genetics 101
Crops with desirable features…
D
e
f
e
n
s
e
…
(Against
predators)
Genetics 101
Color…
Genetics 101
Disease
resistance…
Wheat
rust…
C
o
r
n
s
m
u
t
…
Genetics 101
And even livestock
performance and yield!
Genetics 101
Dodo
Tilacino
One could
resurrect
a lost
species
such as
these…
Trilobite
Great Auk
Genetics 101
Or these
?
Genetics 101
…or things Mendel never imagined…
Genetics 101
…not to mention
the medical
applications and a
slew of other
ethical facets to
debate…
GM
Produce
Genetics 101
Hollywood hype ….or potential reality?
Film: GATTACA (1997)
[first title card]
Plot:
Gattaca Corp.
is an used to say that a child
Vincent:
They
Title
aerospace
firm inCard:
the future."Consider God's handiwork;
Taglines
for
[Vincent
is
looking
at has
thewhat
12-fingered
pianist]
During
this
time
society
analyzes
conceived
in
love
a
greater
chance
who
can
straighten
He
hath
made of
Gattaca (1997)
your
DNA and
determines
where
Irene:
You
didn't
know?
happiness.
They
saySpirit.
that7:13
anymore.
crooked?"
- Ecclesiastes
you
belong
in
life.
Ethan
There Is No Gene Fordon't
The
Human
Vincent:
Oh,
knew.
Hawke's
character
was Iborn
with
Howheart
do you
hide when you're running from yourself?
a Irene:
congenital
condition
It's
amazing,
isn't
it?
Vincent:
I'll
never
understand
what
which would cast him out of
Only one criterion
: genetictitle
perfection
card]
Vincent:
fingers
or
it's
how
you
play
getting
a chance Twelve
to travel
in mother
possessed
my[second
toD:one,
put
her
faith
in
Andrew Niccol; with Ethan
space. So
in turn
hestrong
assumes
the
Only
the
succeed
Title
Card:
"I
not
only
think
that
we will
Irene:
That
piece
can
only
be
played
with
twelve.
Hawke,
Uma
Thurman,
Arkin,
identity
of an hands,
athlete who has
God's
rather than her local Alan
Jude Law,
Loren Dean,
Gore Vidal,
withhimMother
Nature,
I think
Mother
genes tamper
that would allow
to
Ernest Borgnine, Blair Underwood,
geneticist.
achieve
his dream of space
wants us to." - Willard
Gaylin
Tony Shalhoub.
(PG-13, 108 min.)
travel.
Genetics 101
Alba & his proud owner, Eduardo Kac; transgenic artist
Genetics 101
Glow
-inthedark
B
u
n
n
i
e
s
!
Alba, the
fluorescent
bunny.
Photo: Chrystelle Fontaine
Genetics 101
Book…
Art exhibition in Rio…
Genetics 101
Could I be genetically
modified to roar?
Genetics 101
Did you know?
The actor who played Wedge in
the original Star Wars trilogy
has a famous nephew: actor
Ewan McGregor, who plays the
young Obi-Wan in the new Star
Wars film.
Betsy Ross is the
first real person to
ever have been
the head on a
Pez dispenser!
Scientists at a University in Ontario,
Canada have discovered that the part
of Einstein's brain thought to be
related to mathematical reasoning the inferior parietal region - was 15
percent wider on both sides than a
normal brain.
It’s time to get back to Mendel!
Genetics 101
• Through selective cross-breeding over many generations,
Mendel discovered that certain traits show up in offspring
without any blending of parent characteristics.
– For instance, the pea flowers are either purple or white-intermediate colors do not appear in the offspring of crosspollinated pea plants.
• This was revolutionary because the reigning biological theory of
the day suggested a blending, that is, taking our previous
example, a purple flower crossed with a white flower would
produce say a lavender or some such color between the parental
colors….and yet we find that this IS NOT SO!.
Genetics 101
• Lesson 1: Chromosomes & Genes
MA
Hi, I’m a
Chromosome!
As well as
genetic
• This is a chromosome
variety!
A gerbil gets half its
chromosomes from its
mom and the other half
from its dad…this ensures
pairs of chromosomes
KID
PA
Genetics 101
Why do we need chromosomes ?
Chromosomes hold
genes. (units of inheritance usually
Gene here!
occurring at specific locations;
Physically, a gene is a sequence of
DNA bases that specify the order of
amino acids in an entire protein or,
in some cases, a portion of a protein)
There are different versions of genes, called
alleles, that chromosomes carry. Some alleles
are DOMINANT (overriding gene) while
others are recessive (masked gene in presence
of dominant).
Genetics 101
Consider Mendel’s seeds as
an alternate way of looking
at it…
Here is the
mathematical matrix
behind the results...
Smooth
S
S
W
Ss Ss
rin s
kl s
Ss Ss
ed
Every single “child” must be…?
Genetics 101
•While Mendel's research
was with plants, the basic
underlying principles of
heredity that he
discovered also apply to
gerbils because the
mechanisms of heredity
are essentially the same
for both...
It also applies to cats…
and any DNA-dependent life-form!
Genetics 101
What, exactly is a gerbil?
Taxonomy
Order: Rodentia
Suborder: Myomorpha
Family: Cricetidae
Sub-Family: Gerbillinae
Genus: Meriones
Species: unguiculatus
Meriones unguiculatus
What's in the name ?
"Meriones"
means
Greek for "warrior"
means
So, taxanomically,
I’m a
"rodere" (rodent) clawed warrior!!
means
gnawing,
"unguiculatus"
I’m an SRCS
natural!
Latin for "with claws "
"to gnaw "
Genetics 101
Origin and Habitat
Mongolian gerbils (desert rat, sand rat, antelope rat, jird) are native
to eastern Mongolia, northeast China, and western Manchuria.
They live in a variety of terrains, including deserts, bush country
arid steppes, low plains, grasslands, and mountain valleys.
In 1954, eleven pairs were
brought to the United States
from a research laboratory in
Japan. The offspring of these
gerbils were the nucleus for
most research colonies in the
United States today.
Genetics 101
I’m a 4toed jerboa
I’m a bushy-tailed jird, a gerbil’s closest relative!
Genetics 101
Behavior & Diet
Gerbils are gregarious!
Genetics 101
diurnal/nocturnal…
(active during both day and night)
sand-bathing
gnawing
calisthenics
Genetics 101
scratching & digging
and industrious—
building extensive
burrows, often with
several entrances.
"March, 5th, 1989: After several months,
I now feel that these strange little rodents
have finally accepted me as one of their
own."
Genetics 101
Some unusual behaviors…
Food envy
"Whenever any of our gerbils finds a particularly tasty
bit of food, it will run into a corner and make a sudden,
sharp right turn ...to keep food away from the others.
However, the comical thing about this is that the gerbil
usually ends up right next to another gerbil, who tries to
steal the food away from him. This behavior also occurs
when there are no other gerbils around." Gail Seigel
•Thumping
•Nasal greeting
•Aggression
winking
•PEW sway
Pup retrieval
licking
Genetics 101
PEW sway
All PEW’s exhibit a swaying motion which is
triggered by assuming a normal stance and evidence
by an unconscious drift…
standing
drifting
return to drift again
Genetics 101
PEW sway
It looks a lot like this:
Genetics 101
moulting
A grown-up, faded-out Schimmel (the tail keeps its orange), and a
young Schimmel (looks like a DEH).
Genetics 101
juvenile
Stages of the
nutmeg molt
adult
Genetics 101
Some adorable pre-molt young
Polar Fox (F)
Spotted Silver Nutmeg
(M)
Silver Nutmeg (M)
Spotted Agouti (M)
Honey Cream (M)
Ruby Eyed White (M)
Spotted Black (M)
Spotted Gray Agouti (F)
Molting
Genetics 101
Their diet
consists of seeds,
leaves, stems,
and roots; to
some extent, food
is stored in
burrows (easily
observed through
their habit of
covering their
food dishes or
stashing their
seeds).
Juveniles feeding
Genetics 101
Farming … EVERY gerbil’s
dream…
Genetics 101
Uses
As research
animals, gerbils
comprise less than
0.5% of the total
number of rodents
used annually. As pets,
gerbils are popular
because they are
curious, clean, and
easy to maintain and
handle.
Douglas Adams was
dangerously close to the
mark!
Genetics 101
A sample paragraph from
Finally, if Wolbachia
infilarial
nematodes
behaves
as a reproductive
“Tetracycline
treatment
and
sex-ratio
distortion:
a role for
parasite, some of the effects of tetracycline might derive from an
Wolbachia
moultingdetermined
of filarial
interfer-ence
withinthe
the manipulations
by nematodes?”
Wolbachia(Bandi
et al., 1999).
We emphasiseL.
thatSimoncini
the three
M. Casiraghi
J.W.McCall
hypothesesare not mutually exclusive (see Bandi et al.,
L. H. Cramer L. Sacchi C. Genchi
2001b).Despite growing interest and intense research focused on the
antifilarial effect of
and itsC.
application
J.tetracycline
H. Werren
Bandi in the therapy of
human onchocerciasis (Hoerauf et al., 2000a), the results of the first
paper published on this subject (Bosshardtet al., 1993) have not yet
Dipartimento
di Patologia
Animale,
been fully evaluated
and discussed.In
this study,
tetracycline
Universita`
di Milano, Milan,
treatments were applied
at differentlarval
stagesItaly
(L) of the filaria
College
of Veterinary
The University
ofgerbil
Georgia,
Athens, GA, USA
Brugia
pahangi inMedicine,
its experi-mental
host (the
Meriones
Dipartimento
di Produzione
Animale,
Universita`
Parma,
Italy
unguiculatus).
The antifi-larial
effects
recorded di
in Parma,
Bosshardt
et al.’s
paper can be summarised
as follows:
Dipartimento
di Biologia Animale,
Universita` di Pavia, Pavia, Italy
Department of Biology, University of Rochester, Rochester, NY, USA
Genetics 101
So far only
two people
have
connected
gerbils to a
greater
understanding
of the laws of
physics…the
author of
Doctor Fun
and…
Genetics 101
Here is a
working
example:
Water Balance
Kangaroo Rat
Water gain (ml/day)
Ingested in liquid
0
1500 (60%)
Ingested in food
6.0 (10%)
750 (30%)
54.0 (90%)
250 (10%)
60.0 (100%)
2500 (100%)
Evaporation
43.9 (73%)
900 (36%)
Urine
13.5 (23%)
1500 (60%)
Feces
2.6 (4%)
100 (4%)
60.0 (100%)
2500 (100%)
Derived from metabolism
Water Loss (ml/day)
Human
Source: Kangaroo Rat data from Schmidt-Nielsen. Animal Physiology: Adaptation and
Environment, 4th ed. Cambridge: Cambridge University Press, 1990, p. 339.
Genetics 101
Aesthetics…
In the year 1506, the great inventor, engineer, and
artist Leonardo da Vinci painted on a piece of pine
wood, a young Florentine woman, Monna (or Mona)
Lisa. Leonardo himself loved the portrait so much
that he always carried it with him, until it was sold
in France to Francois I, by Leonardo
himself. Today, the Mona Lisa hangs in the Louvre
Museum in Paris and is, without doubt, the most
famous painting in the world.
When people describe the portrait, the two words
most often used are "enigmatic", meaning
perplexing or baffling, and "alluring", meaning
tempting, desiring, and attracting. The eyes seem to
look directly at you no matter where you stand
relative to her. And the smile, there is something
about that smile, but what is it? No one seems to
come up with a good explanation of the
smile. While the smile has often been copied, no
artist can quite recreate or duplicate the smile.
Mongolian Lisa ca. 2005
Genetics 101
Seeing
Beauty
The Japanese once did a
study on defining the
attributes of a beautiful face
of a woman, and they
concluded one of the most
important attributes is a
relationship between the
outer tips of the eyes and the
center point of the lower
lip. Those three points
should form the ends of an
equilateral triangle.
Is this the key to Mona?
What did this mean?
I knew geometry
was needed for
something!
Genetics 101
Art of all sorts…
Antler totem
of the Gobi
Judith
H.
Block
Genetics 101
Recognize the name?…Is this
how the cosmetic giant
started?..if so…gerbils are the
springboards to unimaginable
entrepreneurial feats…
Thomas B. ~ age 8
Mary K. ~ age 8
Genetics 101
reproduction
Breeding onset is between 65-85 days of age in females and 70-85
days in males.
Gerbils are polyestrous
and breed is
year round;
Spontaneous
ovulation
ovulation is spontaneous. The duration of the estrous cycle is 4-6
days. Gerbils used as breeders are permanently paired (they form
semi-stable annually
monogamous
Mating is
usually, but not
periodic,
thatpairs).
is, based
upon
always, nocturnal.
common in mammals and is
a definite cycle. This is
contrasted with induced
ovulation (certain rodents,
rabbits) which is initiated by
copulation.
Genetics 101
reproduction
The average gestation period is 25 days.
A fertile postpartum estrus occurs in 60-85% of gerbils, and
simultaneous lactation and gestation may prolong gestation up to
42 days due to delayed implantation.
The average litter size is 4-6.
The young are weaned at 21
days; weaning weight is 2025 grams. If the postpartum
estrus is not utilized, the
dam resumes cycling
following weaning.
Genetics 101
any
all
‘start’: Romantic
dinner, etc.
‘finish’ : birth!
25 days…w/nursing gap b/w
Genetics 101
newborn
1 week
The young weight approximately 3 grams at birth, are
hairless, and have closed eyelids and ears.
Genetics 101
Cannibalization is
rare; if it does
occur, the litter is
usually small and
is the dam’s first.
…if it comforts you any:
chickens eat chicken!
The female may destroy a litter if it’s very small or if she stops
lactating. This may be a wild , survival behavior.
A dam may desert her litter or cannibalize it if she is disturbed ,
overcrowded or ill.
Most females are fairly reliable mothers.
Fostering abandoned pups is possible if host dam has a litter of
similar age.
A pregnant and nursing gerbil must have a constant water supply.
Regularly check that the water bottle is filled and working properly. If
the water bottle runs dry, the mother gerbil may have to resort to
sacrificing one of her pups as a source of liquid so she can continue to
nurse the litter.
Genetics 101
Sexing
Male gerbils are mostly distinguished from female gerbils by
noting the greater anogenital distance in the males—that is,
the distance between their urinary and anal openings. This is
best accomplished by lifting their tails and comparing them.
male
Other determinants include: female
The scrotum of the male
d
The scent gland (m:larger; this
female is older..)
The nipples (female)
The size of their body
(m:larger)
d
Genetics 101
If the means of your genetic research is reproduction,
what do you do with all the kids?
Genetics 101
“You Gotta Eat!”
We here at SRCS honor the longstanding
proven tradition of the CHECKERS
philosophy…
Genetics 101
Circle of life issues
* note: no gerbils were harmed in the making of this tutorial
Genetics 101
GenEthics...
26 Then God said, "Let us make man in our image, in our
How is this different from Eugenics?
and let
them rule over the fish of the sea and the
Howlikeness,
do you decide
who
[b]
of the
air, over
staysbirds
and who
(ahem)
… the livestock, over all the earth, and
over
all the
creatures that move along the ground."
doesn’t
stay?
27
So God created man in his own image,
Dei
Trivia: Jude•Imago
Law's character
in the image of God he created him;
•Healthmale and female he created them. asks to be called by his
middle name,
Eugene.
•Cultural
"Eugene" comes from the
28 God blessed them and said to them, "Be fruitful mandate
•Genotypic
andborn," which
Greek for "well
Jerome
"Eugenics"
(the
increase in number; fill the earth and subdue
it. is.
Rule
over the
demand
eu[gen[ics 7y1 jen4iks8 n.pl.
•Stewardship
science
of improving
fish
of
the
sea
and
the
birds
of
the
air
and
over
every
livingthe
< Gr eugencs, the movement devoted
hereditary qualities
of a race
vs. Sanctity
•Behavior
creature that moves on the ground."
to improving the human species through
the control of hereditary factors in mating
Genesis 1:26-28
or breed) is the central theme
of the film.
Genetics 101
Stewardship
As a believer one must
confront the cultural
mandate as a purposedriven reality—Why?
1. Knowledge (we know
It is
a returning
of
about
it)
“Godnature
has chosen
reveal
totothe
Himself”
2. Passion: a fleshing out of
conforming to theand
Image
redemptive
of Christ
Garden…a
restorative ethic!
How do we do this?…how do
we subdue?
Naming (authority): God
named Adam, Adam names
living things, Adam named Eve
(we name kids, pets, cars,
streets, houses, etc.)
Spreading out/Exploring:
Note Babel reversal of what?
Cultivate/Nurture:
landscaping, manicuring,
trimming, mowing!….and the
list goes on!
Genetics 101
Handling
A gerbil is easily lifted by scooping it up in one’s hands, where it
usually remains without restraint. A gerbil can also be lifted by
gently grasping the base of the tail to move the animal from one
enclosure to another.
or
Note: Few
photos are
available due
to
professional
sensitivity;
attempt only
if trained by
an expert
Genetics 101
Showing
Judging
The judges will be looking out
for certain things, below is a list
of how the points are scored:
Type - 20
Condition - 20
Colour - 20
Size - 15
Fur - 10
Ears - 5
Eyes - 5
Tail and Tuft - 5
Total = 100
Courtesy of
NGS
Penalty points are to be deducted as
follows:
Disease or intractability - Excess fat - 10 points max
DISQUALIFICATION
Moulting - 10 points max
Sores, scabs, or wounds - Dirty/stained fur - 10 points max
DISQUALIFICATION
Dirty Show pen - 5 points max
Missing fur - 10 points max
Genetics 101
Q: If horses eat hay and cows don’t,
A: long
I don’t
know…motorcycles
how
does
it take to get to the
have doors!
moon by don’t
bicycle?
Genetics 101
Are you ready to wander
into Geneland?
Genetics 101
The mother and father each have a pair of
alleles on six dimensions (the loci) that
control visible characteristics:
A -- controls the color of the belly
C – controls coat pattern; can lighten or
colorpoint (darker extremities)
E -- controls the amount of yellow
G -- controls the amount of gold  grey
P -- controls eye color/coat intensity
Sp -- controls spotting
Genetics 101
For the sake of simplicity, we will initially focus on the
belly color--the ‘A’ locus.
• Because genes can be either dominant or recessive,
there does exist, at times, a tension between them.
Recessive alleles only
Dominant alleles
“get what they want
always “get what
want” when paired
they want” and
vs
with another recessive
over power
allele that wants the
recessive alleles;
same thing; these are
these are
represented by a lower
represented by a
case a
capital A
Genetics 101
For example: There are three scenarios at the A locus
which determines whether the gerbil will be selfcolored (belly is same color as coat…such as...)
Black
Silver nutmeg
Nutmeg
Genetics 101
or if it will be non-self colored (belly is cream or
white…such as...)
Dark-Eyed Honey
Argente
golden
Golden agouti
(wild color)
Genetics 101
Scenario 1: AA; homozygous dominant
Scenario 2: Aa; heterozygous
“same”
Scenario 3: aa; homozygous recessive
“other”
Toddlers at 2-3
wks (left);
juveniles at 6
wks (right)
Genetics 101
Scenario 1: AA; homozygous dominant
White
belly!
A
AA
In this scenario you
White would also end up with
belly! a non-self gerbil, a
gerbil with a white belly.
Both dominant genes
want the gerbil to have a
white belly. So the
dominant genes agree
That’s what I said… and the gerbil is nonself.
A
Genetics 101
Scenario 2: Aa; heterozygous
Solid
belly!
a
White
belly!
A
Oh, okay…
Aa
In this scenario you would
end up with a non-self
gerbil, a gerbil with a white
belly. The dominant gene and
the recessive gene disagree.
But a dominant gene will
always win against a
recessive gene for the same
trait. So the recessive gene
goes along with what the
dominant gene wants and the
gerbil is non-self.
Genetics 101
Scenario 3: aa; homozygous recessive
Solid
belly!
a
aa
In this scenario you
Solid
would end up with a
belly! self-colored gerbil, a
gerbil with a solid belly.
Both dominant genes
want the gerbil to have a
solid belly. So the
dominant genes agree
That’s what I said… and the gerbil is selfcolored.
a
Genetics 101
Self-colored or non-self colored?
1.
2.
Non-self:
A-
3.
Self: aa
Self: aa
4.
Self: aa
5.
Non-self: A-
Genetics 101
Colors?
3.
golden
agouti
1.
lilac
2.
burmese
4.
darkeyed
honey
black
5.
(DEH)
Genetics 101
Review
Self
A
A
A
Non-self
a
a a
Genetics 101
Phenotype & Genotype
The difference between a gerbil's phenotype and genotype
is very simple. Look at the picture of the gerbil below and
describe what its coloring looks like. Then read the row of
letters next to the picture.
AaCCEeGgPpspsp
Phenotype: “white
belly, golden coat with
black ticking & black
eyes”
Genotype
Genetics 101
Your verbal
description of
the gerbil in the
photo is its
phenotype.
The row of letters
you read is its
genotype.
A phenotype and a genotype can tell you the same thing, they
are just different ways of expressing it.
A gerbil's genotype is basically scientific shorthand for a
description of what the gerbil looks like as well as what it
masks.
For example, instead of saying "The gerbil has a white belly
and black eyes" I could say say "The gerbil is AaPp".
Genetics 101
To someone that knows which traits correspond
with "A" and "P", I am saying the same thing!
Genetics 101
Each locus (pair of chromosomes that determine a certain trait,
represented by a pair of letters) stands for a certain trait on the
gerbil. Aa stands for one trait, while CC stands for another,
and spsp stands for yet another.
When you are writing a
genotype, the dominant alleles
(CAPITAL letters) always
precede the recessive alleles
(lower-case letters).
Remember the "geno" in
genotype stands for "gene".
A
a
Genetics 101
A phenotype is the physical description of something:
it's shape, size, color, texture, etc. Each gerbil's official
coat color name is also it's phenotype.
Consider the
“siamese” cat? You
know that means “a
cat with dark points”
or a “colorpoint.”.
The gerbil to the right is an "agouti". That
means "a gerbil with black eyes, a golden coat
with black ticking, and a white belly".
Remember the "ph" in physical, as in physical
description, for the "ph" in phenotype.
Genetics 101
So….The Genotype is the actual genetic
code (expressed and unexpressed/masked)
A protein called the Agouti protein has a
major effect on the amount of melanin
injected into the growing hair. The protein
causes a banding effect on the hair by
triggering a sudden change from the
production of eumelanin (black/brown
pigment) to phaeomelanin (red/yellow
pigment). An example of this coloration
would be like the color of a wild rabbit. The
term 'Agouti' actually refers to a South
American rodent that exemplifies this type of
hair. (& our wild colored gerbil!)
The Phenotype of an organism is what
is expressed…in other words, what it looks like…
Genetics 101
Let’s review allele pairing
Match the term with the proper allele pairs:
dark eyes
homozygous recessive
Pp
heterozygous
pp
pink eyes
homozygous dominant
PP
dark eyes
What does the P locus code for?
(rec. carrier)
Eye color!
Genetics 101
Inheritance
Heredity: Crash Course
Biology #9
Lets say you have one agouti gerbil that you know is Aa
for the 'A' locus. Her mate is a black gerbil that you know
is aa. (Note: refer to your gerbil color sheet/genotype
handout) What will their babies be? To find this out, you
need to draw a Punnett Square. For one locus (two alleles),
draw a box and divide it into four quadrants like so...
•Punnett Square - A simple table
used by geneticists to determine the
outcome of various combinations of
alleles.
Genetics 101
Write the male's genetics across the top, and the
female's genetics down the side. Each allele
should be split to border one square.
P1: Parental
cross
Black male: aa
P1
a
a
A
a
Agouti female: Aa
We are now ready to cross
the parents!
Genetics 101
P
1
a
a
Next, complete the table by combining
the pairs of the alleles as if you were
multiplying two variables.
A
P1
a
A
a
Their children become ‘F1‘ which
stands for first Filial generation
(offspring; 1st kids!)
a
Aa
a
Aa
aa
aa
Each box must
have two letters!
Genetics 101
Let’s interpret the results…
These are your possibilities.
P1
a
A Aa
a
aa
a
Aa
Aa
2/4 = ½
Aa
50%
aa
aa
The agouti and black gerbil can
have babies that carry what is
inside that square.
aa
2/4 = ½
These percentages are
called F1 probabilities-the result of the P1
cross
50%
Genetics 101
Let’s interpret the results…
Because half of the genetic
rectangle is taken by Aa, and
the other half of the genetic
rectangle is taken by aa, there is
a 50% chance of getting babies
with Aa and a 50% chance of
getting babies that carry aa. You
could still end up getting all Aa
or all aa, but the possibility for
each is there.
These are your possibilities.
Aa
2/4 = ½
Aa
50%
aa
aa
2/4 = ½
So what does this really tell you?
The babies could be either self or non-self: solid
bellied or white bellied…or a combo of either.
50%
Genetics 101
Let’s interpret the results…
These are your possibilities.
+
Aa
Aa
Agouti female:
Aa
Black male:
aa
2/4 = ½
50% heterozygous
aa
aa
So what does this really tell you?
The babies could be either self or non-self
2/4 = ½
50% homozygous
recessive
Genetics 101
STEPS to determine the genotypes from
parent organisms
1. write down your "cross" (mating)
2. draw a Punnett square
3. "split" the letters of the genotype for
each parent & put them "outside" the Psquare
4. determine the possible genotypes
of the offspring by filling the squares
5. summarize results (genotypes [allele
pairs & percentages] & phenotypes of
offspring )
6. bask in the glow of your
accomplishment !
Genetics 101
Try your hand at another P1 cross (focusing
only on the A locus: P1: nutmeg (aa)x arg. gold.(AA)
Suppose I have a
homozygous Nutmeg male
and I want to breed him with
a homozygous Argente
Golden female. What are
their probabilities of belly
colors?
STEP 1. write down your
"cross" (mating)
cThe LORD ofthe GERBILS d
Cage 23
Both here are homozygous at locus A!
Nutmeg; m
aa CC
ee GG Pp
Argente golden, spotted; f
AA CC EE GG pp
Genetics 101
2. draw a Punnett square
a
a
A Aa
Aa
A Aa
Aa
3. "split" the letters of the
genotype for each parent & put
them "outside" the P-square
4. determine the possible
genotypes of the offspring by
filling the squares
5. summarize results (genotypes
[allele pairs & percentages] &
phenotypes of offspring )
Shown on next
slide!
Genetics 101
Let’s interpret the results…
These are your possibilities.
+
Aa
Aa
Nutmeg male: Arg. gold female:
aa
AA
4/4 = 1
100% heterozygous
Aa
Aa
So what does this really tell you?
The babies can only be non-self! (white-bellied)
Genetics 101
Making sense?
Good. Now
remember that all of
the examples above
only deal with the
'A' locus, but there
are several other
genes that affect a
gerbil's coat color.
There are six
different loci that all
play off each other,
and this can result in
many many different
color variations!
Let’s try 3
loci!
Genetics 101
The mother and father each have a pair of
alleles on six dimensions (the loci) that
control visible characteristics; we’ll choose 3:
A -- controls the color of the belly
C – controls coat pattern; can lighten or
colorpoint (darker extremities)
E -- controls the amount of yellow
G -- controls the amount of gold  grey
P -- controls eye color/coat intensity
Sp -- controls spotting
Genetics 101
We’ll need 3 Punnett Squares…
…one for each locus
1. Fill in the parents:
nutmeg, m:
arg. gold, f:
a
a
G
A Aa
Aa
G GG
GG
Aa
G GG
GG
A Aa
2. Fill in the squares
aa CC ee GG Pp
AA CC EE GG pp
G
P
p
p
Pp
pp
p
Pp
pp
3. Calculate the probabilities
Genetics 101
P1: nutmeg, m: aa CC ee GG Pp arg. Gold, f: AA CC EE GG pp
3. Calculate the probabilities
4. Summarize stats
a
a
G
A Aa
Aa
G GG
GG
p Pp
A Aa
Aa
G GG
GG
p
AA: 0/4 = 0%
Aa: 4/4 = 100%
aa: 0/4 = 0%
G
GG: 4/4 =100%
Gg: 0/4 = 0%
gg: 0/4 = 0%
P
Pp
p
pp
pp
PP: 0/4 = 0%
Pp: 2/4 = 50%
pp: 2/4 = 50%
Genetics 101
4. Summarize stats
AA: 0/4 = 0%
Aa: 4/4 = 100%
aa: 0/4 = 0%
GG: 4/4 =100%
Gg: 0/4 = 0%
gg: 0/4 = 0%
PP: 0/4 = 0%
Pp: 2/4 = 50%
pp: 2/4 = 50%
Aa
GG
Pp
50%
Aa
GG
pp
50%
Therefore: AaGGPp
50% Non-self, gold, dark-eyed
AaGGpp
50% Non-self, gold, pink-eyed
Genetics 101
Parents:
aa CC ee GG Pp sp[+]sp[+] Nutmeg
AACC EEGG pp Spsp[+] Argente Golden, sp
One of the parents is spotted: 1/2 of the offspring are spotted.
/// Probabilities at the different loci:
_A_ ___C_ ____E__ __G___ ____P_______
1.00 Aa 1.00 CC 1.00 Ee 1.00 GG
0.50 Pp 0.50 pp
/// Probabilities of the 2 colour(s):
0.5000 Aa CC Ee GG Pp Golden Agouti
0.5000 Aa CC Ee GG pp Argente Golden
Genetics 101
Good work!..Let’s expand to six loci!
Genetics 101
The mother and father each have a pair of
alleles on six loci :
A -- controls the color of the belly
C – controls coat pattern; can lighten or
colorpoint (darker extremities)
E -- controls the amount of yellow
G -- controls the amount of gold  grey
P -- controls eye color/coat intensity
Sp -- controls spotting
Genetics
101
Don’t write anything
down yet…just follow
along…
We’ll need 6 Punnett Squares…
1. Fill in the parents and filial squares:
black, m: aa Cc(b) Ee GG Pp spsp slate, f: aa Cc(h) Ee gg Pp spsp
a
a
a
aa aa
C c(b)
C CC Cc(b)
E
e
E EE Ee
a
aa aa
c(h) Cc(h) c(b)c(h)
e
G
G
g Gg Gg
g Gg Gg
P
p
P PP Pp
p Pp
pp
Ee ee
sp sp
sp
sp
spsp
spsp
spsp
spsp
Genetics 101
1. Calculate filial probabilities:
black, m: aa Cc(b) Ee GG Pp slate, f: aa Cc(h) Ee gg Pp
a
a
a
aa aa
C c(b)
C CC Cc(b)
E
e
E EE Ee
a
aa aa
c(h) Cc(h) c(b)c(h)
e
AA: 0/4 = 0%
Aa: 0/4 = 0%
aa: 4/4 = 100%
CC: 1/4 = 25%
Cc(b):1/4 = 25%
Cc(h): 1/4 = 25%
c(b)c(h): 1/4 = 25%
Ee ee
EE: 1/4 = 25%
Ee: 2/4 = 50%
ee: 1/4 = 25%
Genetics 101
Summarize stats
AA: 0/4 = 0%
Aa: 0/4 = 0%
aa: 4/4 = 100%
aa 100%
CC: 1/4 = 25%
Cc(b):1/4 = 25%
Cc(h): 1/4 = 25%
c(b)c(h): 1/4 = 25%
CC
Cc(b)
Cc(h) c(b)c(h)
25%
EE: 1/4 = 25%
Ee: 2/4 = 50%
ee: 1/4 = 25%
EE
ee 25%
Ee
50%
Therefore? There seems to be a lot of variety… why is this
so?…what aspect of the parents led to such possibilities?
…(let’s finish the other three loci)
Genetics 101
1. Calculate filial probabilities:
black, m: aa Cc(b) Ee GG Pp slate, f: aa Cc(h) Ee gg Pp
g
G G
Gg Gg
P
P
p
PP Pp
g
Gg Gg
p
Pp
Gg: 4/4 = 100%
pp
PP: 1/4 = 25%
Pp: 2/4 = 50%
pp: 1/4 = 25%
sp sp
sp
sp
spsp
spsp
spsp
spsp
spsp: 4/4 = 100%
Genetics 101
Summarize stats
Gg: 4/4 = 100%
Gg
100%
PP: 1/4 = 25%
Pp: 2/4 = 50%
pp: 1/4 = 25%
PP
Pp
spsp: 4/4 = 100%
pp 25%
50%
spsp 100%
Therefore? Let’s view the data on all loci and generate a list of
probable colours...
Genetics 101
P1 cross: results
A
C
E
aa 100% CC 25% EE 25%
Cc(b) 25% Ee 50%
Cc(h) 25% ee 25%
c(b)c(h) 25 %
G
Gg 100%
P
sp
PP 25% spsp100%
Pp 50%
pp 25%
12 Probable colors
0.4219 aa C- E-Gg P- Black
0.0156 aa CCee Ggpp Arg Nutmeg
0.1406 aa c[b]c[h] E-Gg P- Siamese 0.0156 aa Cc[h]ee Gg pp ?Lt Arg
0.0938 aa C- ee Gg P- ? Nutmeg
Nutmeg
0.0625 aa c[b]c[h] -- Gg pp PEW 0.0156 aa Cc[b] ee Gg pp unkn clr
0.0469 aa CC E- Gg pp Lilac
Overwhelmed?--this is rare…
0.0469 aa CC ee Gg P- Nutmeg
most are more straightforward
0.0469 aa Cc[b] E- Gg pp Sapphire
and predictable...
0.0469 aa Cc[h] E- Gg pp Dove
0.0469 aa c[b]c[h] ee Gg P- ? Lt Clrpt Nutmeg
Genetics 101
A derivative color chart
Genetics 101
A family tree ~ courtesy of www.
Geocities/Tokyo
Spotted Siamese
Female
(front)
Male (rear)
F1 gen. From cage 22
(black
spotted/burmese
couple)
Genetics 101
What then is the difference between a
Spotted, Pied, or Patched gerbil?
Spotted: usually take the
form of a white tip to the
nose, a white spot on the
forehead, a larger white
spot just behind the ears
and also a white tip to the
tail. (May have any
combo of the former– must
have the tail-tip.)
Genetics 101
Pied: The simple answer is that
any gerbil with more extensive
white markings than “spotted”
will be described as pied.
These markings can be;
 A white collar linking the
white spot behind the head to
the white chest patch.
A white line joining all three
"classic" head spots together.
OR Irregular white markings
on the rump or tail
Genetics 101
Because these markings vary so
much I have heard different names
for different types of pied. For
example, gerbils with just the line
are called Striped and those with
just the collar, Collared. Gerbils
with both the line and the collar
have been called Dutch due to the
resemblance to mice and rabbits of
that name.
Gerbils with the irregular markings
are called Variegated, Mottled, or
Patched.
Genetics 101
Which is which?
At this point we will simply refer to
gerbils with additional markings as
“spotted” or “pied”.
Pied ?
Spotted ?
Patched ?
Genetics 101
Spotted, pied, or mottled?
pied
patched
spotted
Spotted Siamese
Female
(front)
Male (rear)
F1 gen. From cage 22
(black
spotted/burmese
couple)
c Cage 1(’04-’05)
d
siblings
Siamese spotted; male
Siamese spotted; female
aac(b)c(h)EEGGPp Spsp+
dad
aac(b)c(h)EEGGPp Spsp+
Cage 22
parents
mom
Genetics 101
We’ll need 6 Punnett Squares…
1. Fill in the parents and filial squares:
sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp
c(b) c(h)
a
a
a
aa aa
c(b)c(b)c(b) c(b)c(h)
E
E
E EE EE
a
aa aa
c(h)c(b)c(h) c(h)c(h)
E EE EE
P
p
P PP Pp
Sp
sp
SpSp
Spsp
Spsp
spsp
G
G
G GG GG
G GG GG
p Pp
pp
Sp
sp
Genetics 101
1. Fill in the parents and filial squares:
sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp
a
a
a
aa aa
c(b) c(h)
c(b)c(b)c(b) c(b)c(h)
E
E
E EE EE
a
aa aa
c(h)c(b)c(h) c(h)c(h)
E EE EE
aa: 4/4 = 100%
c(b)c(b): 1/4 = 25%
c(b)c(h): 2/4 = 50%
c(h)c(h): 1/4 = 25%
EE: 4/4 = 100%
Genetics 101
1. Fill in the parents and filial squares:
sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp
G G
G GG GG
P
P
p
PP Pp
G GG GG
p
Pp
GG: 4/4 = 100%
pp
PP: 1/4 = 25%
Pp: 2/4 = 50%
pp: 1/4 = 25%
Sp
sp
Sp
sp
SpSp
Spsp
Spsp
spsp
SpSp: ¼ = 25%
Spsp: 2/4 = 50%
spsp: ¼ = 25%
Genetics 101
P1 cross: results
A
C
E
aa 100% c(b)c(b) 25% EE 100%
c(b)c(h) 50%
c(h)c(h) 25%
G
GG 100%
P
sp
PP 25% SpSp 25%
Pp 50% Spsp 50%
pp 25% spsp 25%
Now list the probabilities
at each locus... (see above)
Genetics 101
P1 cross: results
A
C
E
aa 100% c(b)c(b) 25% EE 100%
c(b)c(h) 50%
c(h)c(h) 25%
G
GG 100%
P
sp
PP 25% SpSp 25%
Pp 50% Spsp 50%
pp 25% spsp 25%
Probable
colors:
Now configure
& calculate the rest of the genotypes…
poss. Genotypes
Phenotype
Frequency
aa c(b)c(b) EE GG PP
Burmese
6.25%
aa c(b)c(b) EE GG Pp
Burmese
12.5%
aa c(b)c(b) EE GG pp
PEW (Pink Eyed White)
6.25%
1.c(b)c(h)
Calculate
each
aa
EE GG
PP percentage:
Siamese
12.5%
aa c(b)c(h) EE GG Pp
Siamese 2. Identify the color25%
A% x C% x E% x G% x P% = % for that genotype
aa c(b)c(h) EE GG pp
PEW
12.5%
aa
c(h)c(h)
EE GG
(Dark-Tailed White)
6.25%
= burmese
Eg.
aa c(b)c(b)
EEPP
GG PPDTW
aa c(h)c(h) EE GG Pp
DTW
12.5%
1 x .25EE GG
x 1 pp
x 1 x .25
aa c(h)c(h)
PEW= 0.0625 = 6.25%
6.25%
Genetics 101
P1 cross: results
A
C
E
aa 100% c(b)c(b) 25% EE 100%
c(b)c(h) 50%
c(h)c(h) 25%
G
GG 100%
P
sp
PP 25% SpSp 25%
Pp 50% Spsp 50%
pp 25% spsp 25%
Distribution of 9 gene combinations over the colours:
poss. Genotypes
aa c(b)c(b) EE GG PP
aa c(b)c(b) EE GG Pp
aa c(b)c(b) EE GG pp
aa c(b)c(h) EE GG PP
aa c(b)c(h) EE GG Pp
aa c(b)c(h) EE GG pp
aa c(h)c(h) EE GG PP
aa c(h)c(h) EE GG Pp
aa c(h)c(h) EE GG pp
Phenotype
Burmese
Burmese
PEW (Pink Eyed White)
Siamese
Siamese
PEW
DTW (Dark-Tailed White)
DTW
PEW
Frequency
6.25%
12.5%
6.25%
12.5%
25%
12.5%
6.25%
12.5%
6.25%
What about
the
Genetics
101
P1 cross: results
spotted locus?
poss. Genotypes
Phenotype
aa c(b)c(b) EE GG PP
aa c(b)c(b) EE GG Pp
aa c(b)c(b) EE GG pp
aa c(b)c(h) EE GG PP
aa c(b)c(h) EE GG Pp
aa c(b)c(h) EE GG pp
aa c(h)c(h) EE GG PP
aa c(h)c(h) EE GG Pp
aa c(h)c(h) EE GG pp
Burmese
Burmese
PEW
Siamese
Siamese
PEW
DTW
DTW
PEW
Frequency
6.25%
12.5%
6.25%
12.5%
25%
12.5%
6.25%
12.5%
6.25%
Results
18.75%
37.5%
18.75%
25%
4 Probable colors
37.5%
25%
18.75%
18.75%
aa c[b]c[h] EE GG Paa c-cEE GG pp
aa c[b]c[b] EE GG Paa c[h]c[h] EE GG P-
Siamese
Pink Eyed White (PEW)
Burmese
Dark Tailed White (DTW)
Both parents are spotted: 1/4 of the offspring die before birth. Of the rest
2/3 are spotted
Genetics 101
SpSp:“spotted
25% lethal
gene” is a lethal
The lethal gene… ¼Note:the
Sp
sp
Sp SpSp Spsp
sp Spsp spsp
1/4
gene… when
present
trims down
(carrier
dies init utero)
the litter to 3/4 its normal size and
½guarantees
Spsp: 50%
spotted
that 2/3
of the
remaining
ones66%
are spotted.
(remaining
or 2/3) Here’s
how…
¼ spsp: 25% unspotted
3/4
(remaining 33% or 1/3)
*do not include this locus in your
colour probability list…simply
state the case: eg: “Both parents
are spotted: 1/4 of the offspring
die before birth. Of the rest 2/3
are spotted.”
Genetics 101
Now that you’ve plunged
into it this far…
Are you ready to figure
out another family
tree probability?
Genetics 101
’04-’05 Cage 16
Now take some time to master the following steps to
arrive at a probable colour list…
nutmeg; m
aaCCeeGGPp
argente cream;f
AaCc(h)EEGGpp
Genetics 101
STEPS to determine the genotypic probability of offspring
1. write down your "cross" (mating)
2. draw 6 Punnett squares
3. "split" the letters of the genotype for
each parent & put them "outside" the
squares
4. determine the possible genotypes
of the offspring by filling the squares
5. summarize percentages for each locus
6. calculate & list results (genotypes,phenotypes, percentages)
7. Summarize list of probable colors from highest percentage to
lowest percentage.
Genetics 101
We’ll need 5 Punnett Squares…
1. Fill in the parents and filial squares:
nutmeg, m: aa CC ee GG Pp arg. crm, f: Aa Cc(h) EEGG pp
a
a
A Aa Aa
C C
C CC CC
e
e
E Ee Ee
a
c(h) Cc(h)
Cc(h)
E Ee Ee
G
G
G GG GG
P
p Pp
p
pp
G GG GG
p Pp
pp
aa aa
Note: if both parents
are unspotted (spsp),
don’t bother with the
sixth P-square.
Genetics 101
P1 cross: results
A
0.50 Aa
C
0.50 CC
E
1.00 Ee
G
P
sp
1.00 GG
0.50 Pp
1.00 sp[+]sp[+]
phenotypes
percentages
0.50 aa
0.50 Cc[h]
Aa CC Ee GG Pp
Golden agouti
0.50 pp
.5 x .5 x 1 x 1 x .5 = .125
25%
Aa CC Ee GG pp
Argente golden
.5 x .5 x 1 x 1 x .5 = .125
Aa Cc(h) Ee GG Pp
Golden agouti
.5 x .5 x 1 x 1 x .5 = .125
Aa Cc(h) Ee GG pp
Argente cream
.5 x .5 x 1 x 1 x .5 = .125
aa CC Ee GG Pp
Black
.5 x .5 x 1 x 1 x .5 = .125
aa CC Ee GG pp
Lilac
.5 x .5 x 1 x 1 x .5 = .125
aa Cc(h) Ee GG Pp
Black
.5 x .5 x 1 x 1 x .5 = .125
aa Cc(h) Ee GG pp
Dove
.5 x .5 x 1 x 1 x .5 = .125
25%
Genetics 101
Cage 16
Nutmeg
aaCCeeGGPp
male
Argente Cream
AaCc(h)EEGGpp
female
Filial probability (6 probable colours):
25%
AaC-EeGGPp
golden agouti
25%
aaC-EeGGPp
black
12.5%
AaCCEeGGpp
argente golden
12.5%
AaCc(h)EeGGpp argente cream
12.5%
aaCCEeGGpp
12.5%
aaCc(h)EeGGpp dove
lilac
Genetics 101
We’ll need 5 Punnett Squares…
1. Fill in the parents and filial squares:
black, m: aa CC EE Gg Pp x black, f: aa CC EE Gg Pp
a
a
a
aa aa
C C
C CC CC
E
E
E EE EE
a
aa aa
C CC CC
E EE EE
G
g
G GG Gg
P
p
P PP Pp
g Gg gg
p Pp
pp
Note: both parents are
unspotted (spsp), don’t
bother with the sixth Psquare.
Genetics 101
P1 cross: results
A
1.00 aa
C
1.00 CC
E
1.00 EE
G
0.25 GG
0.50 Gg
0.25 gg
phenotypes
P
0.25 PP
0.50 Pp
0.25 pp
percentages
aa CC EE GG PP
Black
.25 x .25 = .0625
aa CC EE GG Pp
Black
.25 x .5 = .125
aa CC EE GG pp
Lilac
.25 x .25 = .0625
aa CC EE Gg PP
Black
.5 x .25 = .125
aa CC EE Gg Pp
Black
.5 x .5 = .25
aa CC EE Gg pp
Lilac
. 5 x .25 = .125
aa CC EE gg PP
Slate
.25 x .25 = .0625
aa CC EE gg Pp
Slate
.25 x .5 = .125
aa CC EE gg pp
Ruby-Eyed White
.25 x .25 = .0625
56.25%
18.75%
18.75%
6.25%
Genetics 101
black
aa CC EE Gg Pp
male
black
aa CC EE Gg Pp
female
Filial probability (4 probable colours):
56.25%
aaCCEEG-P-
black
18.75%
AaCCEeggP-
slate
18.75%
aaCCEEGgpp
lilac
6.25%
aaCCEEggpp
BEW
Genetics 101
Some odds & ends so
as to leave this work
unfinished...
"Unfinished
Portrait of George
Washington"
Gilbert Stewart
Genetics 101
• You will now suffer a quiz…
May the Force
be with you…
And thereafter?… An examination !
Genetics 101
the end